Acromag Busworks 900mb series User manual

(217) 352-9330 | [email protected] | artisantg.com

ARTISAN

TECHNOLOGY

GROUP

Your definitive source

for

quality

pre-owned

equipment.

Artisan Technology

Group

Full-service,

independent

repair

center

with

experienced

engineers

and

technicians

on staff.

buy

your

excess,

underutilized,

and

idle

equipment

along

with

credit

for

buybacks

and

trade-ins

Custom

engineering

your

equipment

works

exactly as

you

specify.

•

Critical

and

expedited

services

•

Leasing

Rentals/

Demos

• In

stock/

Ready-to-ship

•

!TAR-certified

secure

asset

solutions

Expert

team

ITrust

guarantee

100%

satisfaction

All

ademarks,

names, a

s a

earing here

are

e property of

pecti

ner

Find the Acromag BusWorks 913MB-0900 at our website: Click HERE

BusWorks®900MB Series

Modbus/RS485 Network I/O Modules

Model 913MB Quad DC Current Input

Model 914MB Quad DC Voltage Input

USER’S MANUAL

ACROMAG INCORPORATED

30765 South Wixom Road

P.O. BOX 437

Wixom, MI 48393-7037 U.S.A.

Tel: (248) 295-0880

Fax: (248) 624-9234

Data and specifications are subject to change without notice.

8500-635-K12F005

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 2 -

Safety Summary - Symbols on equipment:

Means “Caution, refer to this manual for additional

information”.

The information contained in this manual is subject to change

without notice. Acromag, Inc., makes no warranty of any kind

with regard to this material, including, but not limited to, the

implied warranties of merchantability and fitness for a particular

purpose. Further, Acromag, Inc., assumes no responsibility for

any errors that may appear in this manual and makes no

commitment to update, or keep current, the information contained

in this manual. No part of this manual may be copied or

reproduced in any form, without the prior written consent of

Acromag, Inc.

Table of Contents

Page

1.0

INTRODUCTION

………………………………..…….. 2

DESCRIPTION ………………………………………… 2

Key 913MB/914MB Features………..…………….. 3

ACCESSORY ITEMS …………………………………. 4

900MB Configuration Software……..…………….... 4

RS232-to-RS485 Serial Converter…..…………….. 4

Interface Cable………………….……..…………….. 4

Software Interface Package (900C-SIP)………….. 4

AC Current Sensor (Model 5020-350)…………….. 4

2.0

PREPARATION FOR USE

….……………………….. 4

UNPACKING AND INSPECTION ……………………

MODULE INSTALLATION.……………..…………….. 4

Default Mode Switch………………………………… 5

Mounting ……………………………………………… 5

Electrical Connections ……………………………… 5

SOFTWARE INSTALLATION ……………….……….. 6

3.0

MODULE CONFIGURATION

……………………….. 6

INTRODUCTION TO MODBUS……..……………..... 13

MODULE SOFTWARE CONFIGURATION…………. 19

MODULE CALIBRATION…………………..…………. 24

4.0

THEORY OF OPERATION

………………………….. 25

5.0

SERVICE AND REPAIR

..…………………………… 25

SERVICE AND REPAIR ASSISTANCE ……………. 25

PRELIMINARY SERVICE PROCEDURE ..…………. 25

TROUBLESHOOTING………………………………… 25

6.0

SPECIFICATIONS

……………………………………. 26

MODEL NUMBER DEFINITION……………………… 26

ANALOG INPUT SPECIFICATIONS …………..……. 26

DIGITAL OUTPUT SPECIFICATIONS…………….... 26

ENCLOSURE/PHYSICAL SPECIFICATIONS …….. 27

APPROVALS ………………………………………….. 27

ENVIRONMENTAL SPECIFICATIONS….………….. 27

COMMUNICATION INTERFACE SPECIFICATIONS 27

CONFIGURATION AND CONTROLS..……………... 28

SOFTWARE CONFIGURATION……..…………….… 28

List of Drawings Page

Simplified Schematic (4501-853)…..…….……………..… 30

Functional Block Diagram (4501-854)………………….… 30

Network Connections (4501-805)…………..…….………. 31

Electrical Connections (4501-855)……..………….……... 31

Interposing Relay Conn. & Contact Pro. (4501-856)……. 32

Enclosure Dimensions (4501-857) …………………..…… 32

Windows 95/98 & NT are registered trademarks of Microsoft

Corporation. Modbus is a registered trademark of Modicon, Inc.

IMPORTANT SAFETY CONSIDERATIONS

It is very important for the user to consider the possible adverse

effects of power, wiring, component, sensor, or software failures

in designing any type of control or monitoring system. This is

especially important where economic property loss or human life

is involved. It is important that the user employ satisfactory

overall system design. It is agreed between the Buyer and

Acromag, that this is the Buyer's responsibility.

1.0 INTRODUCTION

These instructions cover the hardware functionality of the

transmitter models listed in Table 1. Supplementary sheets are

attached for units with special options or features.

Table 1: Models Covered in This Manual

Series/

Input/Type

Options/Output/

Enclosure/Approvals

Factory

Configuration

913MB -0900 -C

914MB -0900 -C

Notes (Table 1):

1. Agency approvals include CE, UL Listed, and cUL Listed.

2. Include the “-C” suffix to specify factory configuration option.

Otherwise, no suffix is required for standard configuration.

The same circuit board used to build the Model 924MB-0900

is used for these two models. If you are already familiar with the

924MB, operation and specifications of the 913MB/914MB are

similar.

DESCRIPTION

The Acromag 900MB family is a group of process I/O

modules and accessories for Modbus/RS485 network I/O

applications. The Model 913MB-0900 will condition up to four

channels of DC current signals, and provide an isolated RS485

network I/O path utilizing the industry standard Modbus protocol.

The Model 914MB-0900 will condition up to four channels of DC

voltage signals, and provide an isolated RS485 network I/O path

utilizing the industry standard Modbus protocol. Both models

also include four control outputs for high/low limit alarm support,

or for simple ON/OFF control of external devices. The

913MB/914MB contains an advanced technology microcontroller

with integrated downloadable flash memory and EEPROM for

non-volatile program, configuration, calibration, and parameter

data storage. Units are fully reconfigurable via our user-friendly

Windows 95/98



or NT



Configuration Program and the RS485

interface. Once configured, these modules may operate as an

active RS485 network slave connected to other modules and a

host computer.

Each module provides four isolated analog inputs of either

DC current (913MB) or DC voltage (914MB). The modules use a

high resolution, optically-isolated, low noise, Sigma-Delta Analog

to Digital Converter (Σ-∆ADC) to accurately convert the input

signals into digitized values. Inputs include high/low alarm

functionality with open-drain alarm output switches. These output

channels include a yellow LED on the front of the module that

provides visual indication of its state and/or alarm condition.

Additionally, a green “Run” and yellow “Status” LED provide local

feedback of operating mode, system diagnostics, watchdog

timeout, and module status.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 3 -

All 900MB modules are designed to withstand harsh

industrial environments. They feature RFI, EMI, ESD, EFT, and

surge protection, plus low temperature drift, wide ambient

temperature operation, and isolation between signal I/O, power,

and the network. They also have low radiated emissions per CE

requirements. As a wide-range DC-powered device, the unit may

be powered from DC power networks incorporating battery

backup. The unit may also be powered from common 24VAC

power. Since the input is diode-bridge coupled, the unit may be

connected to redundant power supplies, or several units may

safely share a single DC supply. Units are DIN-rail mounted and

removable terminal blocks facilitate ease of installation and

replacement, without having to remove wiring. Transmitter

power, network, and digital output wiring are inserted at one side

of the unit, while input wiring is inserted at the other side. Plug-in

connectors are an industry standard screw clamp type that

accept a wide range of wire sizes.

An optional AC current sensor (Acromag Model 5020-350)

may be used in conjunction with the DC current input circuit of the

Model 913MB-0900 to implement AC current measurement and

alarms for inputs up to 20A rms. The optional AC current sensor

is itself an isolated, accurate, toroidal instrument transformer, that

outputs a safe, low-level DC milliamp signal to the input of the

alarm. As an isolated device, it may also be used to facilitate

input-to-input isolation between inputs of this model. See “AC

Current Sensor” section for more information.

Flexible transmitter functionality, network reprogrammability,

mixed signal I/O, alarm support, and a network interface, all

combine in a single package to make this instrument extremely

powerful and useful over a broad range of applications. Further,

the safe, compact, rugged, reconfigurable, and reliable design of

this transmitter makes it an ideal choice for control room or field

applications. Custom module configurations are also possible

(please consult the factory).

Key 913MB/914MB Module Features:

•Agency Approvals - CE, UL, & cUL Listed.

•Easy Windows



Configuration - Fully reconfigurable via

our user-friendly Windows 95/98



or NT



900MB

Configuration Program.

•RS485/Modbus Network Interface - This proven high

speed interface is highly immune to noise, can operate over

long distances, and allows a large number of modules to be

networked together. The unit communicates using the

industry-standard Modbus command/response protocol.

•Nonvolatile Reprogrammable Memory - This module has

an advanced technology microcontroller with integrated,

non-volatile, downloadable flash memory and EEPROM.

This allows the functionality of this device to be reliably

reprogrammed thousands of times.

•Fully Isolated - Input, outputs, network, and power are all

isolated from each other for safety and increased noise

immunity. Inputs are also isolated from each other for

common mode voltages up to ±4V for increased noise

immunity between channels.

•Discrete or Alarm Outputs - High voltage, high current,

open-drain mosfets provide direct or alarm control of

external devices. Outputs may be activated independently,

via watchdog timeout, or under alarm control in both failsafe

and non-failsafe modes.

Key 913MB/914MB Module Features…continued:

•Flexible Multi-Range Analog Inputs - Select either DC

current or DC voltage input signals according to model.

•Optional AC Current Input (913MB Only) - An optional AC

current sensor can be purchased separately to support AC

current inputs and alarms for this model.

•Self-Diagnostics - Built-in routines operate upon power-up

for reliable service, easy maintenance, and troubleshooting.

A hardware watchdog timer is built into the microcontroller

that causes it to initiate a self reset if the controller ever

“locks up” or fails to return from an operation in a timely

manner.

•High-Speed Data Rates – Supports RS485 communication

rates up to 115K baud.

•Wide Ambient Operation - The unit is designed for reliable

operation over a wide ambient temperature range.

•Wide-Range DC-Power or 24VAC Power - This device

receives power over a wide supply range and the power

terminals are diode-bridge coupled. This makes this

transmitter useful for systems with redundant supplies,

and/or battery back-up. Additionally, the power terminals

are not polarized.

•Watchdog Timer – An I/O watchdog timer function is

included and may be configured for timeout periods up to

65534 seconds (18.2 hours). Timer will timeout if a read or

write operation to any I/O channel does not occur over the

configured time period. Optionally, outputs may be

automatically set to user-defined states following timeout.

Watchdog control of output has higher priority than alarm

control and direct control.

•Hardened For Harsh Environments - The unit will operate

reliably in harsh industrial environments and includes

protection from RFI, EMI, ESD, EFT, and surges, plus low

radiated emissions per CE requirements.

•Convenient Mounting, Removal, & Replacement - The

DIN-rail mount and plug-in type terminal blocks make

module removal and replacement easy.

•High-Resolution Precise A/D Conversion - Transmitters

include a high-resolution, low noise, Sigma-Delta Analog to

Digital Converter (Σ-∆ADC) for high accuracy and reliability.

•LED Indicators - A green LED indicates power. A yellow

status LED will turn on if an input signal is out of calibrated

range, or it flashes if the unit is placed in the default

communication mode. It will also flash rapidly upon

watchdog timeout. A yellow output LED indicates the

ON/OFF state of the associated open-drain output.

•Default Communication Mode - A push-button switch is

provided to set the module to a default set of communication

parameters for baud rate, module address, parity, and

number of stop bits. This provides a convenient way of

establishing communication with the module when its

internal settings are unknown.

•Automatic Self-Calibration – Built-in self-calibration

corrects for temperature drift of the input circuit every 60

seconds.

•Alarm Functionality – Alarm limit checking is always active

for the module. High and/or low limit levels, plus deadband

may be configured at each input. Optionally, failsafe or non-

failsafe alarm outputs may be enabled for each limit. Alarm

control has priority over direct control of an output.

•Configurable Setpoint With Deadband - Includes

programmable deadband to help eliminate switch “chatter”.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 4 -

ACCESSORY ITEMS

The following accessories are available from Acromag.

Acromag also offers other standard and custom transmitters to

serve a wide range of applications (please consult the factory).

900MB Configuration & Control Software (Model 5034-186)

Series 900MB modules are configured with this user-friendly

Windows 95/98



or NT



Configuration Program. Optionally, any

software that supports the Modbus/RTU protocol may be used to

configure and control Series 900MB modules, but the use of this

software makes getting started easier. All module functions are

programmable and downloadable to the modules via this

software. The software also includes on-line help. Non-volatile

memory provides program and configuration storage within the

module. Note that this software may be optionally downloaded

from our website (www.acromag.com) to registered owners of

Series 900MB modules.

RS-232 to RS-485 Serial Adapter (Model 5034-214)

This device is a non-isolated, port-powered, signal converter

for communication between the RS-232 serial port of a personal

computer and the RS-485 network interface of Series 900MB I/O

Modules. It is used in conjunction with the Acromag

Configuration Software for simple reconfiguration, testing, and

troubleshooting of Series 900MB I/O modules. As a port-

powered device, it is not intended for driving fully loaded RS-485

networks over long distances, and does not have sufficient power

to drive terminated networks. The adapter has DB-9F connectors

at both ends and plugs directly into the common DB-9M serial

port connector of most personal computers. The module is

connected to the RS-485 side of this adapter via a separate

interconnecting cable (see Cable 5034-202 described below).

Interface Cable (Model 5034-202)

This 3-wire cable is used to connect the RS-485 side of

Signal Converter 5034-214 to the RS-485 network terminals of

Series 900MB modules. This cable is 8 feet long and has a

DE-9M connector on one end, and three stripped and tinned

wires on the other end. The wires are labeled A, B, and C for

connection to the module D, Dbar, and COM terminals,

respectively.

Series 900MB Software Interface Package (Model 900C-SIP)

The 900C-SIP Software Interface Package combines the

900MB Configuration Software (5034-186), RS-232 to RS-485

Serial Converter (5034-214), Interface Cable (5034-202), and

Instructions (8500-649), into a complete kit for interfacing with

Series 900MB I/O Modules.

AC Current Sensor (Model 5020-350)

For Use With Current Input Module 913MB-0900

This optional sensor is an accurate toroidal instrument

transformer used to convert a sinusoidal 50-60Hz AC current

signal into a low level DC milliampere signal of 0 to 11.17mA.

The input AC current range is a simple function of the number of

turns placed through the toroid as shown in Table 2. This sensor

is isolated and requires no calibration or adjustment. When used

with a 913MB module, it provides redundant input isolation and

may facilitate input-to-input isolation of four channel units.

Table 2: AC Current Sensor Turns & Range

AC Current

Input Range

Primary

Turns

Sensor Output

(Red/Black Wires)

0 to 20A AC 1 0 to 11.17mA DC

0 to 10A AC 2 “

0 to 5A AC 4 “

0 to 2A AC 10 “

0 to 1A AC 20 “

The output wires of this sensor are polarized with red as (+)

plus and black as (-) minus. Normally these output wires are

attached to one end of a user supplied cable while the other end

connects to the 913MB’s process current input terminals.

Input Burden: A function of the wire gauge resistance used for

primary turns (the current carrying wire being monitored).

AC Current Sensor to Transmitter Wiring Distance: 400 feet

maximum for 18 gauge wire. Other wire gauges can be used as

long as the resistance of both wires is less than 5Ω.

Input Overload: The AC current sensor will withstand overload

conditions as follows:

•20 times full scale for 0.01 seconds.

•10 times full scale for 0.1 seconds.

•5 times full scale for 1.0 second.

2.0 PREPARATION FOR USE

UNPACKING AND INSPECTION

Upon receipt of this product, inspect the shipping carton for

evidence of mishandling during transit. If the shipping carton is

badly damaged or water stained, request that the carrier's agent

be present when the carton is opened. If the carrier's agent is

absent when the carton is opened and the contents of the carton

are damaged, keep the carton and packing material for the

agent's inspection. For repairs to a product damaged in

shipment, refer to the Acromag Service Policy to obtain return

instructions. It is suggested that salvageable shipping cartons

and packing material be saved for future use in the event the

product must be shipped.

This module is physically protected

with packing material and electrically

protected with an anti-static bag

during shipment. However, it is

recommended that the module be

visually inspected for evidence of

mishandling prior to applying power.

This circuit utilizes static sensitive

components and should only be

handled at a static-safe workstation.

MODULE INSTALLATION

This transmitter module is packaged in a general purpose

plastic enclosure. Use an auxiliary enclosure to protect the unit in

unfavorable environments or vulnerable locations, or to maintain

conformance to applicable safety standards. Stay within the

specified operating temperature range. As shipped from the

factory, the unit is calibrated for all valid input ranges and has the

default configuration shown in Table 2 below:

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 5 -

WARNING: Applicable IEC Safety Standards may require that

this device be mounted within an approved metal enclosure or

sub-system, particularly for applications with exposure to voltages

greater than or equal to 75VDC or 50VAC.

Table 2: 913MB/914MB Default Factory Configuration

PARAMETER

CONFIGURATION/CALIB

Module Address 247

Baud Rate 9600bps

Parity None

Stop Bits 1 or 2 (When Parity=None)

Response Delay 0 (No Delay)

Watchdog Time 0 (Disabled)

Output Timeout States All ON (Timer Disabled)

Input Range (913MB) 0-20mA DC

Input Range (914MB)

10V DC

Limit Configuration (Each Input) Alarm Outputs Disabled

High Limit Value (Each Input) 100% (High Endpoint)

Low Limit Value (Each Input) -100% (Low Endpoint)

Deadband (Each Input) 1%

Note: Do not confuse the Default Factory Configuration noted

above with the Default Communication Mode, which refers to the

fixed baud rate, module address, parity, and stop bit settings

achieved by pushing the Default Mode button until the status LED

flashes ON/OFF. The Default Communication Mode will

temporarily over-ride any factory configuration of baud rate,

module address, parity, and stop bits with settings of 9600bps,

247, None, and 1 or 2, respectively. It is provided as a

convenient means of achieving communication with a module

when these parameters are unknown.

Your application will typically differ from the default factory

configuration and will require that the transmitter be reconfigured

to suit your needs. This can be easily accomplished with

Acromag’s user-friendly Windows 95/98



or NT



900MB

Configuration Program. Configuration is normally done prior to

field installation. Refer to MODULE SOFTWARE

CONFIGURATION of Section 3.0 for detailed instructions.

Default Mode Switch

A push-button default mode switch and status LED are

provided at the front of the module as a convenient way of

communicating with the module when its baud rate and address

settings are unknown. Push and hold this button until the Status

LED flashes ON/OFF to indicate the module is in the Default

Communication Mode with a fixed module address of 247, baud

rate of 9600bps, no parity, and 1 or 2 stop bits. It is most

convenient to configure a module in this mode, then leave the

default mode by pressing this button again until the Status LED

stops flashing (constant ON or OFF), or by resetting the module.

The Default Mode is disabled following a software or power-on

reset. New communication parameters (for baud rate, address,

and parity) will take effect following a reset of the module after

leaving the Default Mode.

IMPORTANT: The default mode is indicated via a flashing status

LED. However, if an input is left open or floating, the status LED

may turn ON to indicate a signal over-range condition and this will

mask default mode indication. DO NOT LEAVE UNUSED

CHANNELS OPEN OR FLOATING. It is recommended that you

short unused input channels.

Mounting

Refer to Enclosure Dimensions Drawing 4501-857 for

mounting and clearance dimensions.

DIN Rail Mounting: This module can be mounted on "T" type

DIN rails. Use suitable fastening hardware to secure the DIN rail

to the mounting surface. Units may be mounted side-by-side on

1-inch centers for limited space applications.

"T" Rail (35mm), Type EN50022: To attach a module to this

style of DIN rail, angle the top of the unit towards the rail and

locate the top groove of the adapter over the upper lip of the rail.

Firmly push the unit towards the rail until it snaps solidly into

place. To remove a module, first separate the input terminal

block(s) from the bottom side of the module to create a clearance

to the DIN mounting area. Next, insert a screwdriver into the

lower arm of the DIN rail connector and use it as a lever to force

the connector down until the unit disengages from the rail.

Electrical Connections

Digital output, network, power, and input terminals can

accommodate wire from 12-24 AWG, stranded or solid copper.

Strip back wire insulation 1/4-inch on each lead before installing

into the terminal block. Analog input wiring should be shielded

twisted-pair. Since common mode voltages can exist on signal

wiring, adequate wire insulation should be used and proper wiring

practices followed. It is recommended that transmitter network,

digital I/O, and power wiring be separated from the input signal

wiring for safety, as well as for low noise pickup. Note that input,

power, network, and digital I/O terminal blocks are a plug-in type

and can be easily removed to facilitate module removal or

replacement, without removing individual wires. Be sure to

remove power before unplugging the terminals to uninstall the

module, or before attempting service. All connections must be

made with power removed.

CAUTION:

Risk of Electric Shock - More than one

disconnect switch may be required to de-energize the

equipment before servicing.

1. Power: Refer to Electrical Connections Drawing 4501-855.

Variations in power supply voltage within rated limits has

negligible effect on module accuracy. For supply

connections, use No. 14 AWG wires rated for at least 75°C.

The power terminals are diode bridge-coupled and not

polarized. The unit is powered from 10-36VDC, or 24VAC

only.

2. Inputs: Connect inputs per Electrical Connections Drawing

4501-855. Observe proper polarity when making input

connections (see label for input type). Unused inputs should

not be left open or floating and should be shorted. For

increased noise immunity, the voltage inputs are isolated

channel-to-channel for common mode voltages up to ±4V.

Be careful that your application does not inadvertently exceed

these limits, or damage to the unit may result.

IMPORTANT: Noise and/or jitter on the input signal has the

effect of reducing (narrowing) the instrument’s deadband and

may produce switch chatter when using the alarm output.

The long term effect of this will reduce the life of mechanical

relays if connected to these outputs. To reduce this

undesired effect, you should increase the effective deadband.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 6 -

3. Outputs (Coils): All outputs are the open-drains of n-

channel mosfets whose source terminals share return (RTN).

Externally wired output pullups may be required. All outputs

include transient voltage suppressers and integrated

snubbers, but may require additional protection when

switching inductive loads (see below). Refer to the

SPECIFICATIONS section for output specifications and see

the module side label for terminal designations. Note that

these outputs are for current-sinking (low-side switching)

applications only. Observe proper polarity when making

connections. The output circuit as a group is electrically

isolated from the input, power, and network circuits. If

necessary, an interposing relay can be used to switch higher

currents as illustrated in the Interposing Relay Connection

Drawing 4501-856.

Note: Digital outputs go to their OFF state following a

software or power-on reset of the module. Outputs may be

optionally sent to user-defined states following a watchdog

timer timeout.

IMPORTANT - Protection With Inductive Loads: The

output mosfets have integrated shunt diode clamps

connected from drain to source to help protect the output

switch from damaging reverse emf voltages that exist when

controlling inductive loads. You may need to add external

protection local to the inductive load for added protection and

to prevent this emf from being distributed across the

connection media. For DC inductive loads, place a diode

across the load (1N4006 or equivalent) with cathode to (+)

and anode to (-).

5. Network Connections: Wire network as shown in Network

Connections Drawing 4501-805. Network common (COM)

should connect to earth ground at one point.

6. Grounding: See Electrical Connections Drawing 4501-855.

The module housing is plastic and does not require an earth

ground connection.

WARNING: For compliance to applicable safety and

performance standards, the use of shielded cable is

recommended as shown in Drawing 4501-855. Further, the

application of earth ground must be in place as shown in

Drawing 4501-855. Failure to adhere to sound wiring and

grounding practices may compromise safety & performance.

SOFTWARE INSTALLATION - USING SETUP.EXE

The 900MB Configuration Software (Model 900C-SIP) is used

to configure Series 900MB modules and is installed as follows:

1. Start Windows 95/98/NTand insert the 900MB

Configuration Software CDROM into your drive D:.

IMPORTANT: Before continuing with the installation

sequence, be sure to exit any other Windows programs that

may be running.

2. Click on the [START] button in the lower left hand corner of

the Windows screen. Then click on the “Run…” icon.

3. In the Run dialogue box, type d:\setup (or m:\setup) in the

Open field and click on [OK]. The setup program will

execute the Installshield Wizard. You may need to click on

the “Setup.exe” icon of the install shield to proceed. On

some machines, the setup.exe program is not started

automatically.

Software Installation…continued:

4. From the introductory Acromag 900MB Setup Screen, click

on [Next>] to proceed.

5. At this point, the 900MB Setup program will prompt you for

your “Name” and “Company”. Fill in this information, then

click on [Next>].

6. Now you will be prompted for a destination directory. You

may click on [Browse] to change the default directory, or

[Next>] to accept “C:\ProgramFiles\Acromag\900MB” as the

default. You may also click on [Back] to return to the prior

screen and make any changes.

7. At this point you will be prompted for a program folder name.

You may type a new name, use the scroll bar to select an

existing program folder, or click on [Next>] to accept the

“Acromag 900MB” default folder name.

8. Now you will be presented with your selections and you

should verify if they are correct. Press [Next>] to continue

and begin copying files, or press [Back] to return to prior

screens and make any changes.

9. After the Configuration Program files have been copied to

your hard drive, you will be prompted to click on [Finish] to

complete the setup.

10. Now click on the [Acromag 900MB] program folder icon at

the bottom of your windows screen, then click on the

Acromag 900MB program icon to start the Configuration

Program (Programs-Acromag 900MB-Acromag 900MB

Configuration icon).

3.0 MODULE CONFIGURATION

This module needs to be configured for your application.

Configuration is easily accomplished using Acromag’s Windows

95/98



or NT



Modbus Configuration Software and an RS232-to-

RS485 signal converter. It is not required to use the Acromag

software to communicate with the Series 900MB, as any software

capable of sending Modbus protocol commands over an RS485

network can be used. However, the Acromag software provides

an easy to use Windows format for communicating with the

module that does not require advanced familiarity with the

Modbus protocol.

Modbus registers are organized into the following reference

types identified by the leading number of the reference address:

Reference

Description

0xxxx Read/Write Discrete Outputs or Coils. A 0x

reference address is used to drive output data to

a digital output channel.

1xxxx Read Discrete Inputs. The ON/OFF status of a 1x

reference is controlled by the corresponding

digital input channel.

3xxxx Read Input Registers. A 3x reference register

contains a 16-bit number received from an

external source—e.g. an analog signal.

4xxxx Read/Write Output or Holding Registers. A 4x

(binary or decimal), or to send the data from the

CPU to an output channel.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 7 -

Notes (Register Map):

1. The “x” following the leading character represents a four-

digit address location in user data memory. The leading

character is generally implied by the function code and

omitted from the address specifier for a given function. The

leading character also identifies the I/O data type.

2. The ON/OFF state of discrete inputs and outputs is

represented by a 1 or 0 value assigned to an individual bit in

a 16-bit data word. With respect to mapping, the LSB of the

word maps to the lowest numbered channel of a group and

channel numbers increase sequentially as you move

towards the MSB. Unused bits are set to zero.

Modbus functions operate on register map registers to

configure and control modules. The following table outlines the

I/O modules. You will find it helpful to refer to this map as you

review the Modbus function descriptions later.

Model 913MB/914MB-0900 Register Map

Ref Addr. Description Data Type/Format

Coil Registers (0x References, Read/Write)

0001

Thru

00004

0-3

(0000-

0003)

Four

Discrete

Outputs 0-3

Discrete Output Value.

Addresses a specific bit of

a 16-bit word that controls/

monitors the ON/OFF

status for the output.

Note:

This signal corresponds to

the gate signal of the n-channel

output mosfet. Thus, a read of

this register may not reflect the

actual output level at the drain of

the mosfet if the open-drain is not

pulled up or is left floating.

Excitation must be provided in

order to operate the outputs.

After reset, these registers read 0

(outputs OFF) and these

registers are not maintained in

EEPROM.

A set bit (1) means the

corresponding output is

ON. A clear bit (0) means

the corresponding output is

OFF. The bit position

corresponds to the output

channel number (i.e. output

0 uses bit 0 of the 16-bit

word at address 0, output 1

uses bit 1 of the 16-bit

word at address 1, etc.)

Unused bits of a word are

set to 0.

Bits 15-4: Not Used.

Additionally, unused bits

in range 3-0 are set to 0.

IMPORTANT: Disable the

corresponding limits if you

wish to control the state of

a discrete output directly

via these registers as limit

alarm functionality takes

precedence.

Input Registers (3x References, Read-Only)

0001 0

(0000)

Module

Status

Bit 15: Flash Checksum

1 = Error Flag

0 = No Flash Error

Bit 14: A/D Error Flag

1 = A/D Error

0 = No A/D Error

Bit 13: Default Mode Flag

1 = Default Mode Indication

0 = Not In Default Mode

Bits 12-4: Zero

Bit 3: I/O Watchdog Fault

1 = Watchdog Timeout

0 = No Timeout

Bit 2: Limit Detect Flag

1 = Global Limit Exceeded

0 = No Limit Exceeded

Bits 1-0: Zero

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Input Registers (3x References, Read-Only)

0002 1

(0001)

Current Input

Configuration

913MB

Models

Bits 15-4: Zero

Bits 3,2,1,0: 913MB Input

Range Only

0000 = 0 = 0-20mA DC

0001 = 1 = 4-20mA DC

0010 = 2 = 0-11.17mA DC

0011 = 3 = 0-1mA DC

xxxx = 3-15 = Reserved

0002 1

(0001)

Current Input

Configuration

914MB

Models

Bits 15-4: Zero

Bits 3,2,1,0: 914MB Input

Range Only

0000 = 0 = ±10V DC

0001 = 1 = ±5V DC

0010 = 2 = ±2.5V DC

0011 = 3 = ±1.25VDC

0100 = 4 = ±625mV DC

0101 = 5 = ±313mV DC

0110 = 6 = ±156mV DC

0111 = 7 = ±78mV DC

1xxx = 8-15 = Reserved

0003 2

(0002)

CH 0 Input

Value

Percentage (%)

See Note 5

0004 3

(0003)

CH 0 Status

Value

Bits 15-4: Zero

Bit 3: High Limit Flag

1 = High Limit Exceeded

0 = Below High Limit

Bit 2: Low Limit Flag

1 = Low Limit Exceeded

0 = Above Low Limit

Bits 1,0: Under/Over

Range

00 = In Range;

01 = Overrange;

10 = Under Range;

11 = Not Defined

0005 4

(0004)

CH 1 Input

Value

Percentage (%)

See Note 5

0006 5

(0005)

CH 1 Status

Value

Format Is Same As CH 0

0007 6

(0006)

CH 2 Input

Value

Percentage (%)

See Note 5

0008 7

(0007)

CH 2 Status

Value

Format Is Sam

e As CH 0

0009 8

(0008)

CH 3 Input

Value

Percentage (%)

See Note 5

0010 9

(0009)

CH 3 Status

Value

Format Is Same As CH 0

0011 10

(000A)

CH0 Raw

Count

Raw A/D Count Value

0012 11

(000B)

CH1 Raw

Count

Raw A/D Count Value

0013 12

(000C)

CH2 Raw

Count

Raw A/D Count Value

0014 13

(000D)

CH3 Raw

Count

Raw A/D Count Value

Holding Registers (4x References, Read/Write)

Note:

Changes to Holding Registers take effect following the

next software or power-on reset of the module, except as

noted.

0001 0

(0000)

Slave

Address

Default=

247

1-247

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 8 -

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

Note:

Changes to Holding Registers take effect following the

next software or power-on reset of the module, except as noted.

0002 1

(0001)

Baud Rate

Default=

2, 9600bps

0 = 2400bps; 1 = 4800;

2 = 9600bps (Default);

3 = 14400; 4 = 19200;

5 = 28800; 6 = 38400;

7 = 57600; 8 = 76800;

9 = 115200.

0003 2

(0002)

Parity

Default=

0, None

0 = None (1 or 2 stop bits)

1 = Odd Parity Checking

(1 stop bit)

2 = Even Parity Checking

(1 stop bit)

0004 3

(0003)

I/O

Watchdog

Time

Default=

0, Disabled

Can be set from 1 to 65534

seconds. Set to 65535

(FFFFH) or 0 (0000H) to

disable the watchdog timer

(0000H/disabled is the

default value).

40005 4

(0004)

Output

Channel

Timeout

States

Default=

65535,

Disabled

The four lower order bits of

this 16-bit register value

define the state the output

channels will be

programmed to following a

watchdog timeout. Bit 0

corresponds to channel 0,

bit 1 to channel 1, bit 2 to

channel 2, and bit 3 to

channel 4. Write 65535

(FFFFH) to this register to

leave the outputs

unchanged following a

timeout (this is also the

default value). Note that

watchdog timeout control

takes precedence over

alarm and direct control of

the digital output.

0006 5

(0005)

Response

Delay Time

(Turnaround

Delay)

Default=

0, No Delay

Can be set from 0 to 65500

ticks (1 tick = 1.085us).

This is the additional delay

the module will wait before

responding to a host

message. The default

value is 0 (no delay).

Increase this value if you

are having communication

problems or you encounter

a high degree of error

messages.

0007 6

(0006)

913MB

Input

Configuration

(applies to all

four inputs)

Default=

0, 0-20mA

Bits 15-4: Zero

Bits 3,2,1,0: 913MB Input

Range Only

0000 = 0 = 0-20mA DC

0001 = 1 = 4-20mA DC

0010 = 2 = 0-11.17mA DC

0011 = 3 = 0-1mA DC

xxxx = 4-15 = Reserved

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

Note:

Changes to Holding Registers take effect following the

next software or power-on reset of the module, except as noted.

0007 6

(0006)

914M

Input

Configuration

(applies to all

four inputs)

Default=

0, ±

±±

±10V

Bits 15-4: Zero

Bits 3,2,1,0: 914MB

Input Range Only

0000 = 0 = ±10V DC

0001 = 1 = ±5V DC

0010 = 2 = ±2.5V DC

0011 = 3 = ±1.25VDC

0100 = 4 = ±625mV DC

0101 = 5 = ±313mV DC

0110 = 6 = ±156mV DC

0111 = 7 = ±78mV DC

1xxx = 8-15 = Reserved

0008 7

(0007

CH0 High Limit

Default=

100%

Percentage (%)

See Note 5

0009 8

(0008)

CH0 Low Limit

Default=

-100% (914MB),

0% (913MB)

Percentage (%)

See Note 5

0010 9

(0009

CH0 Deadband

Default= 1%

Percentage (%)

See Note 5

0011 10

(000A)

CH0 Alarm

Output State &

Alarm Output

Enable

Default=0,

Disabled

Bits 15-3: Zero

Bit 2: Alarm Out State

0 = Failsafe (OFF)

1 = Non-Failsafe (ON)

Bit 1: High Limit

1 = Hi Output Enabled

0 = Hi Output Disabled

Bit 0: Low Limit

1 = Lo Output Enabled

0 = Lo Output Disabled

0012 11

(000B)

CH1 High Limit

Default=100%

Percentage (%)

See Note 5

0013 12

(000C)

CH1 Low Limit

Default=

-100% (914MB)

0% (913MB)

Percentage (%)

See Note 5

0014 13

(000D)

CH1 Deadband

Default= 1%

Percentage (%)

See Note 5

0015 14

(000E)

CH1 Alarm

Output State &

Alarm Output

Enable

Default=0,

Disabled

Bits 15-3: Zero

Bit 2: Alarm Out State

0 = Failsafe (OFF)

1 = Non-Failsafe (ON)

Bit 1: High Limit

1 = Hi Output Enabled

0 = Hi Output Disabled

Bit 0: Low Limit

1 = Lo Output Enabled

0 = Lo Output Disabled

0016 15

(000F)

CH2 High Limit

Default= 100%

Percentage (%)

See Note 5

0017 16

(0010)

CH2 Low Limit

Default=

-100% (914MB)

0% (913MB)

Percentage (%)

See Note 5

0018 17

(0011)

CH2 Deadband

Default= 1%

Percentage (%)

See Note 5

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 9 -

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

Note: Changes to Holding Registers take effect following the

next software or power-on reset of the module.

0019 18

(0012)

CH2 Alarm

Output State &

Alarm Output

Enable

Default=0,

Disabled

Bits 15-3: Zero

Bit 2: Alarm Out State

0 = Failsafe (OFF)

1 = Non-Failsafe (ON)

Bit 1: High Limit

1 = Hi Output Enabled

0 = Hi Output Disabled

Bit 0: Low Limit

1 = Lo Output Enabled

0 = Lo Output Disabled

0020 19

(0013)

CH3 High Limit

Default=

20000, 100%

Percentage (%)

See Note 5

0021 20

(0014)

CH3 Low Limit

Default=

-100%(914MB)

0%(913MB)

Percentage (%)

See Note 5

0022 21

(0015)

CH3 Deadband

Default= 1%

Percentage (%)

See Note 5

0023 22

(0016)

CH3 Alarm

Output State &

Alarm Output

Enable

Default=0,

Disabled

Bits 15-3: Zero

Bit 2: Alarm Out State

0 = Failsafe (OFF)

1 = Non-Failsafe (ON)

Bit 1: High Limit

1 = Hi Output Enabled

0 = Hi Output Disabled

Bit 0: Low Limit

1 = Lo Output Enabled

0 = Lo Output Disabled

0024 23

(0017)

Calibration

Access

And

Alternate

Method of

Module Reset

Write 24106 (5E2AH) to

immediately remove

write protection from the

calibration registers that

follow. All other values

apply write protection to

the calibration registers

(except 41429).

Write 41429 (A1D5H) to

this register to cause an

immediate module reset.

This is provided as an

alternate method of

Reset for software that

does not support the

Reset Slave (08)

command.

After a reset, this

protection enabled and

no reset).

This register is not

maintained in

EEPROM.

IMPORTANT: Access to calibration registers 40025 through

40104 is not normally required and writes to these registers

should be avoided to prevent module miscalibration. Shaded

calibration registers apply to the Model 914MB-0900 and

unshaded calibration registers apply to Model 913MB-0900.

0025 24

(0018)

CH0 0-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

0025 24

(0018)

CH0 ±10V

Cal HI Value

(914MB)

Raw A/D Count Value

0026 25

(0019)

CH0 0-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

0026 25

(0019)

CH0 ±10V

Cal LO Value

(914MB)

Raw A/D Count Value

0027 26

(001A)

CH0 4-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

0027 26

(001A)

CH0 ±5V Cal

HI Value

(914MB)

Raw A/D Count Value

0028 27

(001B)

CH0 4-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

0028 27

(001B)

CH0 ±5V Cal

LO Value

(914MB)

Raw A/D Count Value

0029 28

(001C)

CH0

0-11.17mA

Cal HI Value

(913MB)

Raw A/D Count Value

0029 28

(001C)

CH0 ±2.5V

Cal HI Value

(914MB)

Raw A/D Count Value

0030 29

(001D)

CH0

0-11.17mA

Cal LO Value

(913MB)

Raw A/D Count Value

0030 29

(001D)

CH0 ±2.5V

Cal LO Value

(914MB)

Raw A/D Count Value

0031 30

(001E)

CH0 0-1mA

Cal HI Value

(913MB)

Raw A/D Count Value

0031 30

(001E)

CH0 ±1.25V

Cal HI Value

(914MB)

Raw A/D Count Value

0032 31

(001F)

CH0 0-1mA

Cal LO Value

(913MB)

Raw A/D Count Value

0032 31

(001F)

CH0 ±1.25V

Cal LO Value

(914MB)

Raw A/D Count Value

0033 32

(0020)

CH0

±625mV Cal

HI Value

Raw A/D Count Value

0034 33

(0021)

CH0

±625mV Cal

LO Value

Raw A/D Count Value

0035 34

(0022)

CH0

±313mV Cal

HI Value

Raw A/D Count Value

0036 35

(0023)

CH0

±313mV Cal

LO Value

Raw A/D Count Value

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 10 -

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

Note: Changes to Holding Registers take effect following the

next software or power-on reset of the module.

40037 36

(0024)

CH0

±156mV Cal

HI Value

Raw A/D Count Value

40038 37

(0025)

CH0

±156mV Cal

LO Value

Raw A/D Count Value

40039 38

(0026)

CH0 ±78mV

Cal HI Value

Raw A/D Count Value

40040 39

(0027)

CH0 ±78mV

Cal LO Value

Raw A/D Count Value

40041 40

(0028)

CH1 0-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

40041 40

(0028)

CH1 ±10V

Cal HI Value

(914MB)

Raw A/D Count Value

40042 41

(0029)

CH1 0-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

40042 41

(0029)

CH1 ±10V

Cal LO Value

(914MB)

Raw A/D Count Value

40043 42

(002A)

CH1 4-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

40043 42

(002A)

CH1 ±5V Cal

HI Value

(914MB)

Raw A/D Count Value

0044 43

(002B)

CH1 4-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

0044 43

(002B)

CH1 ±5V Cal

LO Value

(914MB)

Raw A/D Count Value

0045 44

(002C)

CH1

0-11.17mA

Cal HI Value

(913MB)

Raw A/D Count Value

0045 44

(002C)

CH1 ±2.5V

Cal HI Value

(914MB)

Raw A/D Count Value

0046 45

(002D)

CH1

0-11.17mA

Cal LO Value

(913MB)

Raw A/D Count Value

0046 45

(002D)

CH1 ±2.5V

Cal LO Value

(914MB)

Raw A/D Count Value

0047 46

(002E)

CH1 0-1mA

Cal HI Value

(913MB)

Raw A/D Count Value

0047 46

(002E)

CH1 ±1.25V

Cal HI Value

(914MB)

Raw A/D Count Value

0048 47

(002F)

CH1 0-1mA

Cal LO Value

(913MB)

Raw A/D Count Value

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

Note: Changes to Holding Registers take effect following the

next software or power-on reset of the module.

0048 47

(002F)

CH1 ±1.25V

Cal LO Value

(914MB)

Raw A/D Count Value

0049 48

(0030)

CH1

±625mV Cal

HI Value

Raw A/D Count Value

0050 49

(0031)

CH1

±625mV Cal

LO Value

Raw A/D Count Value

0051 50

(0032)

CH1

±313mV Cal

HI Value

Raw A/D Count Value

0052 51

(0033)

CH1

±313mV Cal

LO Value

Raw A/D Count Value

0053 52

(0034)

CH1

±156mV Cal

HI Value

Raw A/D Count Value

0054 53

(0035)

CH1

±156mV Cal

LO Value

Raw A/D Count Value

40055 54

(0036)

CH1 ±78mV

Cal HI Value

Raw A/D Count Value

40056 55

(0037)

CH1 ±78mV

Cal LO Value

Raw A/D Count Value

40057 56

(0038)

CH2 0-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

40057 56

(0038)

CH2 ±10V

Cal HI Value

(914MB)

Raw A/D Count Value

40058 57

(0039)

CH2 0-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

40058 57

(0039)

CH2 ±10V

Cal LO Value

(914MB)

Raw A/D Count Value

40059 58

(003A)

CH2 4-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

40059 58

(003A)

CH2 ±5V Cal

HI Value

(914MB)

Raw A/D Count Value

40060 59

(003B)

CH2 4-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

40060 59

(003B)

CH2 ±5V Cal

LO Value

(914MB)

Raw A/D Count Value

40061 60

(003C)

CH2

0-11.17mA

Cal HI Value

(913MB)

Raw A/D Count Value

40061 60

(003C)

CH2 ±2.5V

Cal HI Value

(914MB)

Raw A/D Count Value

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 11 -

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

40062 61

(003D)

CH2

0-11.17mA

Cal LO Value

(913MB)

Raw A/D Count Value

40062 61

(003D)

CH2 ±2.5V

Cal LO Value

(914MB)

Raw A/D Count Value

0063 62

(003E)

CH2

0-1mA Cal

HI Value

(913MB)

Raw A/D Count Value

0063 62

(003E)

CH2 ±1.25V

Cal HI Value

(914MB)

Raw A/D Count Value

0064 63

(003F)

CH2

0-1mA Cal

LO Value

(913MB)

Raw A/D Count Value

0064 63

(003F)

CH2 ±1.25V

Cal LO Value

(914MB)

Raw A/D Count Value

0065 64

(0040)

CH2

±625mV Cal

HI Value

Raw A/D Count Value

0066 65

(0041)

CH2

±625mV Cal

LO Value

Raw A/D Count Value

0067 66

(0042)

CH2

±313mV Cal

HI Value

Raw A/D Count Value

0068 67

(0043)

CH2

±313mV Cal

LO Value

Raw A/D Count Value

0069 68

(0044)

CH2

±156mV Cal

HI Value

Raw A/D Count Value

0070 69

(0045)

CH2

±156mV Cal

LO Value

Raw A/D Count Value

0071 70

(0046)

CH2 ±78mV

Cal HI Value

Raw A/D Count Value

0072 71

(0047)

CH2 ±78mV

Cal LO Value

Raw A/D Count Value

40073 72

(0048)

CH3 0-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

40073 72

(0048)

CH3 ±10V

Cal HI Value

(914MB)

Raw A/D Count Value

40074 73

(0049)

CH3 0-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

40074 73

(0049)

CH3 ±10V

Cal LO Value

(914MB)

Raw A/D Count Value

40075 74

(004A)

CH3 4-20mA

Cal HI Value

(913MB)

Raw A/D Count Value

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

40075 74

(004A)

CH3 ±5V Cal

HI Value

(914MB)

Raw A/D Count Value

40076 75

(004B)

CH3 4-20mA

Cal LO Value

(913MB)

Raw A/D Count Value

40076 75

(004B)

CH3 ±5V Cal

LO Value

(914MB)

Raw A/D Count Value

40077 76

(004C)

CH3

0-11.17mA

Cal HI Value

(913MB)

Raw A/D Count Value

40077 76

(004C)

CH3 ±2.5V

Cal HI Value

(914MB)

Raw A/D Count Value

40078 77

(004D)

CH3

0-11.17mA

Cal LO Value

(913MB)

Raw A/D Count Value

40078 77

(004D)

CH3 ±2.5V

Cal LO Value

(914MB)

Raw A/D Count Value

40079 78

(004E)

CH3 0-1mA

Cal HI Value

(913MB)

Raw A/D Count Value

40079 78

(004E)

CH3 ±1.25V

Cal HI Value

(914MB)

Raw A/D Count Value

40080 79

(004F)

CH3 0-1mA

Cal LO Value

(913MB)

Raw A/D Count Value

40080 79

(004F)

CH3 ±1.25V

Cal LO Value

(914MB)

Raw A/D Count Value

0081 80

(0050)

CH3

±625mV Cal

HI Value

Raw A/D Count Value

0082 81

(0051)

CH3

±625mV Cal

LO Value

Raw A/D Count Value

0083 82

(0052)

CH3

±313mV Cal

HI Value

Raw A/D Count Value

0084 83

(0053)

CH3

±313mV Cal

LO Value

Raw A/D Count Value

0085 84

(0054)

CH3

±156mV Cal

HI Value

Raw A/D Count Value

0086 85

(0055)

CH3

±156mV Cal

LO Value

Raw A/D Count Value

0087 86

(0056)

CH3 ±78mV

Cal HI Value

Raw A/D Count Value

0088 87

(0057)

CH3 ±78mV

Cal LO Value

Raw A/D Count Value

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 12 -

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

0089 88

(0058)

0-20mA Cal

HI Value

(913MB)

Ideal A/D Count Value

0089 88

(0058)

±10V Cal HI

Value

(914MB)

Ideal A/D Count Value

0090 89

(0059)

0-20mA Cal

LO Value

(913MB)

Ideal A/D Count Value

0090 89

(0059)

±10V

Cal LO Value

(914MB)

Ideal A/D Count Value

40091 90

(005A)

4-20mA Cal

HI Value

(913MB)

Ideal A/D Count Value

40091 90

(005A)

±5V Cal HI

Value

(914MB)

Ideal A/D Count Value

40092 91

(005B)

4-20mA Cal

LO Value

(913MB)

Ideal A/D Count Value

40092 91

(005B)

±5V Cal LO

Value

(914MB)

Ideal A/D Count Value

40093 92

(005C)

0-11.17mA

Cal HI Value

(913MB)

Ideal A/D Count Value

40093 92

(005C)

±2.5V Cal HI

Value

(914MB)

Ideal A/D Count Value

40094 93

(005D)

0-11.17mA

Cal LO Value

(913MB)

Ideal A/D Count Value

40094 93

(005D)

±2.5V Cal

LO Value

(914MB)

Ideal A/D Count Value

40095 94

(005E)

0-1mA Cal

HI Value

(913MB)

Ideal A/D Count Value

40095 94

(005E)

±1.25V Cal

HI Value

(914MB)

Ideal A/D Count Value

40096 95

(005F)

0-1mA Cal

LO Value

(913MB)

Ideal A/D Count Value

40096 95

(005F)

±1.25V Cal

LO Value

(914MB)

Ideal A/D Count Value

40097 96

(0060)

±625mV Cal

HI Value

(914MB)

Ideal A/D Count Value

40098 97

(0061)

±625mV Cal

LO Value

(914MB)

Ideal A/D Count Value

40099 98

(0062)

±313mV Cal

HI Value

(914MB)

Ideal A/D Count Value

Model 913MB/914MB-0900 Register Map…continued

Ref Addr. Description Data Type/Format

Holding Registers (4x References, Read/Write)

40100 99

(0063)

±313mV Cal

LO Value

(914MB)

Ideal A/D Count Value

40101 100

(0064)

±156mV Cal

HI Value

(914MB)

Ideal A/D Count Value

40102 101

(0065)

±156mV Cal

LO Value

(914MB)

Ideal A/D Count Value

40103 102

(0066)

±78mV Cal

HI Value

(914MB)

Ideal A/D Count Value

40104 103

(0067)

±78mV Cal

LO Value

(914MB)

Ideal A/D Count Value

1001

This block

mirrors

1xxxx

registers

where

applicable.

Refer to Note 7. 1xxxx

Discrete Input Registers

are mapped to the 41xxx

Holding Register space

using an address offset of

41000.

2001

This block

mirrors

0xxxx

registers

where

applicable.

Refer to Note 7. 0xxxx Coil

Registers are mapped to

the 42xxx Holding Register

space using an address

offset of 42000.

43001 .

This block

mirrors

3xxxx

registers.

Refer to Note 6. 3xxxx

Input registers are mapped

to the 43xxx Holding

address offset of 43000.

Notes (Register Map):

1. Note that the Report Slave ID and Reset Slave functions do

not operate on Register Map locations.

2. Configuration variables stored in holding registers (4xxxx

reference addresses) are maintained in EEPROM, except

for the Calibration Access & Reset Register. Changes to

these registers do not take effect until the next software or

power-on reset of the module.

3. The 914MB A/D Count value is calculated via the

expression: count = (32768*Vin*Gain/Vref)+32768, where

Vref=1.235V. Gain is 1 (±10V range), 2 (±5V), 4 (±2.5V), 8

(±1.25V), 16 (±625mV), 32 (±313mV), 64 (±156mV), and

128 (±78mV). The 913MB A/D Count value is calculated via

the expression: count = (32768*Iin*49.9Ω*Gain/Vref)+

32768, where Vref=1.235V. Gain is 1 (0-20mA & 4-20mA

range), 2 (0-11.17mA range), or 16 (0-1mA range).

4. WARNING: Access to calibration registers 40025 through

40104 is not normally required and writes to these registers

should be avoided to prevent module miscalibration.

5. Input values are 16-bit signed integer values representing

percent with a resolution of 0.005%/lsb. ±20000 is used to

represent ±100%. The full range is –163.84% (-32768

decimal) to +163.835% (+32767 decimal). For example, -

100%, 0% and +100% are represented by decimal values –

20000, 0, and +20000, respectively. Bipolar voltage ranges

(914MB) use ±100% (span of –20000 to +20000), current

ranges (913MB) use 0-100% (span of 0 to 20000). Default

limit values are set to the input range endpoints: -100% on

914MB (Low Limit, -20000), 0% on 913MB (Low Limit, 0),

and +100% (High Limit, +20000). Default deadband is set to

1% (200 on 914MB, 100 on 913MB). Limit checking is

always active.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 13 -

Notes (Register Map)…continued:

6. For your convenience, this module mirrors the contents and

operation of 3xxxx registers into 43xxx holding register

space for systems and controllers that cannot directly

access 3xxxx registers. That is, the 3xxxx registers of this

model can be written to, or read from, using either the

standard methods described in the Modbus specification, or

through mapping (mirroring) to the Holding Register space.

The format of the registers are identical and you only need

to offset your address by 43000. For example: if you want to

read Input Register 1 through the Holding Registers, you

would use the “Read Holding Registers” function with an

address of 43001.

7. For modules with a firmware revision later than 9300-036G

or 9300-103B (913MB), and 9300-027G or 9300-104B

(914MB), the mirroring function as described in Note 6 is

augmented as follows (0xxxx also maps to 42xxx space, and

1xxxx also maps to 41xxx space, where applicable):

For 1xxxx Input Status Registers (where supported), the

return data is reformatted to match the Holding Register

format. For example, if you request Input Status for 12

digital inputs, instead of getting 2 bytes returned with the

first 12 bits representing 12 digital inputs, you will get 12

separate words (2 bytes) instead, with each set to 0000H

(OFF) or FFFFH (ON).

For 0xxxx Coil Registers (where supported), reads are

handled in the same way as noted for 1xxxx Input Status

Registers. That is, you may write to the coil registers using

the “Preset Single Register” function with an address offset

of 42000. Setting the data to 0000H will turn the coil OFF,

while setting the data to FF00H will turn the coil ON.

8. For modules with a firmware revision later than 9300-036G

or 9300-103B (913MB), and 9300-027G or 9300-104B

(914MB), you must limit the number of registers returned by

the Read Holding Register command to no more than 50

registers per request. Requests attempting to access

greater than 50 registers will return Modbus exception code

07 (Negative Acknowledge).

INTRODUCTION TO MODBUS

The Modbus protocol provides an industry standard method

that Series 900MB modules use for parsing messages. Modbus

devices communicate using a master-slave technique in which

only one device (the master) can initiate transactions (called

queries). The other devices (slaves) respond by supplying the

requested data to the master, or by taking the action requested in

the query. The Series 900MB modules are slaves, while a typical

master device is a host computer running appropriate application

software. Masters can address individual slaves, or can initiate a

broadcast message to all slaves. Slaves return a response to all

queries that are addressed to them individually, but no response

is returned to broadcast queries from a master device.

Remote Terminal Unit (RTU) Mode

The Series 900MB modules use the widely accepted Modbus

network protocol in the RTU (Remote Terminal Unit) serial

transmission mode. In RTU mode, each 8-bit message byte

contains two 4-bit hexadecimal characters, and the message is

transmitted in a continuous stream. The format for each byte in

RTU mode is outlined below:

RTU Mode Byte Format

Coding System 8-bit binary, hexadecimal 0-9, A-F, two

hexadecimal characters contained in each

8-bit field of the message.

Bits Per Byte 1 start bit + 8 data bits, lsb sent first + 1bit

for even/odd parity or no bit for no parity +

1 stop bit if parity is used, or 1 or 2 stop

bits with no parity.

Error Check Field Cyclical Redundancy Check (CRC)

A master’s query is comprised of a slave address (or

broadcast), a function code defining the requested action, any

data required, and an error checking field. A slave’s response is

comprised of fields confirming the action taken, any data to be

returned, and an error checking field.

The query and response both include a device address +

function code + data byte(s) + error checking field. If an error

occurred in the receipt of the query, or if the slave is unable to

perform the requested action, the slave will return an exception

message as its response (see Modbus Exceptions). The error

check field allows the master to confirm that the message

contents are valid.

Modbus Message Framing

A Modbus message is placed in a frame by the transmitting

device. A frame is used to mark the beginning and ending point

of a message allowing the receiving device to determine which

device is being addressed and to know when the message is

completed. It also allows partial messages to be detected and

errors flagged as a result.

RTU mode messages start with a silent interval of at least 3.5

character times implemented as a multiple of character times at

the baud rate being used on the network (indicated as t1t2t3t4

below). The first field transmitted is the device address. The

allowable characters transmitted for all fields are hexadecimal

values 0-9, A-F.

A networked device continuously monitors the network,

including the silent intervals, and when the first field is received

(the address), the device decodes it to determine if it is the

addressed device. Following the last character transmitted, a

similar silent interval of 3.5 character times marks the end of the

message and a new message can begin after this interval. A

typical message frame is shown below.

RTU Message Frame

Start

Addr.

Function

Data

CRC

End

t1t2t3t4 8 bits 8 bits nx8 bits 16 bits t1t2t3t4

The entire message must be transmitted as a continuous

stream. If a silent interval of more than 1.5 character times

occurs before completion of the frame, the receiving device

flushes the incomplete message and assumes the next byte will

be the address field of a new message.

In similar fashion, if a new message begins earlier than 3.5

character times following a previous message, the receiving

device assumes it is a continuation of the previous message.

This will generate an error, as the value in the final CRC field will

not be valid for the combined messages.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 14 -

How Characters Are Transmitted Serially

When messages are transmitted on Modbus serial networks,

each character or byte is sent in the order of Least Significant Bit

(LSB) to Most Significant Bit (MSB) as outlined below (left to

right):

RTU Character Framing (No Parity)

Start 0 1 2 3 4 5 6 7 Stop Stop

RTU Character Framing (With Parity)

Start 0 1 2 3 4 5 6 7 Parity Stop

Note that an additional stop bit is normally transmitted to fill

out the character frame for no parity. Acromag units will accept

one or two stop bits with no parity.

Modbus Addresses

The master device addresses a specific slave device by

placing the 8-bit slave address in the address field of the

message. Valid addresses are from 1-247. When the slave

responds, it places its own address in this field of its response to

let the master know which slave is responding. Address 0 is

reserved for the broadcast address, which all slave devices on a

network recognize. A slave does not issue a response to

broadcast messages. Further, not all function messages support

the broadcast address.

With respect to data addresses, all data addresses in

Modbus messages are referenced to 0, with the first occurrence

of a data item addressed as item number zero. Further, a

function code field already specifies which register group it is to

operate on (i.e. 0x, 1x, 3x, or 4x reference addresses). For

example, holding register 40001 is addressed as register 0000 in

the data address field of the message. The function code that

operates on this register specifies a “holding register” operation

and the “4xxxx” reference is implied. Holding register 40108 is

addressed as register 006BH (107 decimal).

Modbus Functions

The function code field of a message frame contains the 8

bits that tell the slave what kind of action to take. Valid codes are

in the range 1-255. Not all codes apply to a module and some

codes are reserved for future use.

The following table highlights the subset of standard Modbus

functions supported by the Model 913MB/914MB-0900 module

(the reference register addresses that the function operates on

are also indicated):

CODE

FUNCTION

REFERENCE

01 (01H) Read Coil (Output) Status 0xxxx

03 (03H) Read Holding Registers 4xxxx

04 (04H) Read Input Registers 3xxxx

05 (05H) Force Single Coil (Output) 0xxxx

06 (06H) Preset Single Register 4xxxx

08 (08H) Reset Slave

Hidden

15 (0FH) Force Multiple Coils (Outputs) 0xxxx

16 (10H) Preset Multiple Registers 4xxxx

17 (11H) Report Slave ID

Hidden

These functions are used to access the registers outlined in

the register map presented in the prior section for sending and

receiving data. Note that the Report Slave ID and Reset Slave

commands do not operate on register map registers.

When the slave device responds to the master, it uses the

function code field to indicate either a normal (error-free)

response, or that some kind of error has occurred (an exception

response). A normal response simply echoes the original

function code of the query, while an exception response returns a

code that is equivalent to the original function code with its most

significant bit (msb) set to a logic 1. For example, the Read

Holding Registers command has the function code 0000 0011

(03H). If the slave device takes the requested action without

error, it returns the same code in its response. However, if an

exception occurs, it returns 1000 0011 (83H) in the function code

field and also appends a unique code in the data field of the

response message that tells the master device what kind of error

occurred, or the reason for the exception (See Modbus

Exceptions). The master’s application program must handle the

exception response. It may choose to post subsequent retries of

the original message, it may try sending diagnostic messages to

the slave, or it may simply notify the operator an exception error

has occurred.

The following paragraphs describe the Modbus functions

supported by this model. For a better understanding of Modbus,

please refer to the register map as you review this material.

Read Coil Status (01)

This command will read the ON/OFF status of discrete

outputs or coils (0x reference addresses) in the slave. For

913MB/914MB models, its response is equivalent to reading the

gate signals of the n-channel mosfets that drive the outputs.

Broadcast transmission is not supported.

The Read Coil Status query specifies the starting coil (output

channel) and quantity of coils to be read. Coils correspond to the

discrete open-drain outputs of this transmitter and are addressed

starting from 0 (up to 4 coils addressed as 0-3 for this model).

The Read Coil Status in the response message is packed as

one coil or channel per bit of the data field. The output status is

indicated as 1 for ON (sinking current), and 0 for OFF (not

conducting). The LSB of the first data byte corresponds to the

status of the coil addressed in the query. The other coils follow

sequentially, moving toward the high order end of the byte. Since

this model has only 4 outputs, the remaining bits of the data byte

will be set to zero toward the unused high order end of the byte.

The following example reads the output channel status of coils 0-

3 at slave device 247:

Read Coil Status Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 1 (01)

Starting Address High Order 0 (00)

Starting Address Low Order 0 (00)

Number Of Points High Order 0 (00)

Number Of Points Low Order 4 (04)

Error Check (LRC or CRC) --

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 15 -

Note that the leading character of the 0x reference address is

implied by the function code and omitted from the address

specified. In this example, the first address is 00001, referenced

via 0000H, and corresponding to coil 0.

Read Coil Status Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 1 (01)

Byte Count 1 (01)

Data (Coils 3-0) 10 (0A)

Error Check (LRC or CRC) --

To summarize, the status of coils 3-0 is shown as the byte

value 0A hex, or 00001010 binary. Coil 3 is the fifth bit from the

left of this byte, and coil 0 is the LSB. The four remaining bits

(toward the high-order end) are zero. Reading left to right, the

output status of coils 3..0 is ON-OFF-ON-OFF. This is

summarized as follows:

Bin

Hex

Coil

Read Holding Registers (03)

This command will read the binary contents of holding

registers (4x reference addresses) in the slave device. Broadcast

transmission is not supported.

The Read Holding Registers query specifies the starting

are addressed starting at 0 (registers 1-16 addressed as 0-15).

The Read Holding Registers response message is packed as two

bytes per register, with the binary contents right-justified in each

byte. For each register, the first byte contains the high order bits

and the second byte the low order bits.

The following example reads holding registers 40006…40008

(Channel 0 high limit value, low limit value, deadband value) at

slave device 247:

Read Holding Register Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 3 (03)

Starting Address High Order 0 (00)

Starting Address Low Order 5 (05)

Number Of Points High Order 0 (00)

Number Of Points Low Order 3 (03)

Error Check (LRC or CRC) --

Read Holding Register Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 3 (03)

Byte Count 6 (06)

Data High (Register 40006) (3A)

Data Low (Register 40006) 75%=15000 (98)

Data High (Register 40007) (13)

Data Low (Register 40007) 25%=5000 (88)

Data High (Register 40008) (00)

Data Low (Register 40008) 1%=200 (C8)

Error Check (LRC or CRC) --

To summarize, the contents of register 40006 (two bytes) is

the channel 0 high limit of 75% (15000=3A98H). The contents of

(5000=1388H). The contents of register 40008 is the channel 0

deadband value (two bytes) of 1% (200=00C8H).

IMPORTANT: For modules with a firmware revision later than

9300-036G or 9300-103B (913MB), and 9300-027G or 9300-

104B (914MB), you must limit the number of registers returned by

the Read Holding Register command to no more than 50

registers per request. Requests attempting to access greater

than 50 registers will return Modbus exception code 07 (Negative

Acknowledge).

Read Input Registers (04)

This command will read the binary contents of input registers

(3x reference addresses) in the slave device. Broadcast

transmission is not supported.

The Read Input Registers query specifies the starting register

and quantity of registers to be read. Note that registers are

addressed starting at 0--registers 1-16 are addressed as 0-15.

The Read Input Registers response message is packed as

two bytes per register, with the binary contents right-justified in

each byte. For each register, the first byte contains the high

order bits and the second byte the low order bits.

The following example reads input registers 30003 & 30004

(Channel 0 input value and status) at slave device 247:

Read Input Registers Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 4 (04)

Starting Address High Order 0 (00)

Starting Address Low Order 2 (02)

Number Of Points High Order 0 (00)

Number Of Points Low Order 2 (02)

Error Check (LRC or CRC) --

Read Input Registers Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 4 (04)

Byte Count 4 (04)

Data High (Register 30003) (3E)

Data Low (Register 30003) 80%=16000 (80)

Data High (Register 30004) (00)

Data Low (Register 30004) 136 (88)

Error Check (LRC or CRC) --

To summarize, the contents of register 30003 (two bytes)

is the channel 1 input value of 80% (16000=3E80H). The

contents of register 30004 (two bytes) is the channel 0 status

flags of 136 (0088H)—i.e. flagging high limit exceeded.

Force Single Coil (05)

This command will force a single coil/output (0x reference

address) ON or OFF. For broadcast transmission, this function

forces the same coil in all networked slaves.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 16 -

The Force Single Coil query specifies the coil reference

address to be forced, and the state to force it to. The ON/OFF

state is indicated via a constant in the query data field. A value of

FF00H forces the coil to be turned ON (i.e. the gate of the

corresponding n-channel mosfet is set high), and 0000H forces

the coil to be turned OFF (i.e. the gate of the corresponding

output mosfet is set low). All other values are illegal and will not

affect the coil. Note that coils are referenced starting at 0—up to

4 coils are addressed as 0-3 for this model and this corresponds

to the discrete output channel number. The following example

forces discrete output 3 ON at slave device 247:

Force Single Coil Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 5 (05)

Coil Address High Order 0 (00)

Coil Address Low Order 3 (03)

Force Data High Order 255 (FF)

Force Data Low Order 0 (00)

Error Check (LRC or CRC) --

The Force Single Coil response message is an echo of the

query as shown below, returned after executing the force coil

command. No response is returned to broadcast queries from a

master device.

Force Single Coil Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 5 (05)

Coil Address High Order 0 (00)

Coil Address Low Order 3 (03)

Force Data High Order 255 (FF)

Force Data Low Order 0 (00)

Error Check (LRC or CRC) --

Preset Single Register (06)

This command will preset a single holding register (4x

reference addresses) to a specific value. Broadcast transmission

is supported by this command and will act to preset the same

The Preset Single Register query specifies the register

reference address to be preset, and the preset value. Note that

registers are addressed starting at 0--registers 1-16 are

addressed as 0-15. The Preset Single Registers response

message is an echo of the query, returned after the register

contents have been preset.

The following example writes a baud rate of 9600bps to

holding register 40002 (Baud Rate) at slave device 247:

Preset Holding Register Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 6 (06)

Preset Data High Order 0 (00)

Preset Data Low Order 2 (02)

Error Check (LRC or CRC) --

Preset Holding Register Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 6 (06)

Preset Data High Order 0 (00)

Preset Data Low Order 2 (02)

Error Check (LRC or CRC) --

The response simply echoes the query after the register

contents have been preset. No response is returned to broadcast

queries from a master device.

Force Multiple Coils (15)

This command will simultaneously force a sequence of coils

(0x reference addresses) either ON or OFF. Broadcast

transmission is supported by this command and will act to force

the same block of coils in all networked slaves.

The Force Multiple Coils query specifies the starting coil

reference address to be forced, the number of coils, and the force

data to be written in ascending order. The ON/OFF states are

specified by the contents in the query data field. A logic 1 in a bit

position of this field requests that the coil turn ON, while a logic 0

requests that the corresponding coil be turned OFF. Unused bits

in a data byte should be set to zero. Note that coils are

referenced starting at 0—up to 4 coils are addressed as 0-3 for

this model and this also corresponds to the discrete output

channel number.

The Force Multiple Coils normal response message returns

the slave address, function code, starting address, and the

number of coils forced, after executing the force instruction. Note

that it does not return the byte count or force value. The following

example forces outputs 1 & 3 OFF, and 0 & 2 ON for coils 0-3 at

slave device 247:

Force Multiple Coils Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 15 (0F)

Coil Address High Order 0 (00)

Coil Address Low Order 0 (00)

Number Of Coils High Order 0 (00)

Number Of Coils Low Order 4 (04)

Byte Count 01

Force Data High (First Byte) 5 (05)

Error Check (LRC or CRC) --

Note that the leading character of the 0x reference address is

implied by the function code and omitted from the address

specified.

In this example, the first address is 00001 corresponding to

coil 0 and referenced via 0000H. Thus, the data byte transmitted

will address coils 3...0, with the least significant bit addressing the

lowest coil in this set as follows (note that the four unused upper

bits of the data byte are set to zero):

Bin

Hex

Coil

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 17 -

Force Multiple Coils Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 15 (0F)

Coil Address High Order 0 (00)

Coil Address Low Order 0 (00)

Number Of Coils High Order 0 (00)

Number Of Coils Low Order 4 (04)

Error Check (LRC or CRC) --

The normal response returns the slave address, function

code, starting coil address, and quantity of coils forced, after

executing the force instruction. It does not return the byte count

or force data. No response is returned to broadcast queries from

a master device.

Preset Multiple Registers (16)

This command will preset a block of holding registers (4x

reference addresses) to specific values. Broadcast transmission

is supported by this command and will act to preset the same

block of registers in all networked slaves.

The Preset Multiple Registers query specifies the starting

to be written in ascending order. Note that registers are

addressed starting at 0--registers 1-16 are addressed as 0-15.

The Preset Multiple Registers normal response message returns

the slave address, function code, starting register reference, and

the number of registers preset, after the register contents have

been preset. Note that it does not echo the preset values.

The following example writes a new slave address of 200, a

baud rate of 28800bps, and sets parity to even, by writing to

holding registers 40001 through 40003 at slave device 247

(changes to slave address, baud rate, and parity will take effect

following the next software or power-on reset):

Preset Multiple Registers Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 16 (10)

Starting Register High Order 0 (00)

Starting Register Low Order 0 (00)

Number Of Registers High Order 0 (00)

Number Of Registers Low Order 3 (03)

Byte Count 6 (06)

Preset Data High (First Register) 0 (00)

Preset Data Low (First Register) 200 (C8)

Preset Data High (Second Reg) 0 (00)

Preset Data Low (Second Reg) 5 (05)

Preset Data High (Third Reg) 0 (00)

Preset Data Low (Third Reg) 2 (02)

Error Check (LRC or CRC) --

Preset Multiple Registers Example Response

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 16 (10)

Starting Register High Order 0 (00)

Starting Register Low Order 0 (00)

Number Of Registers High Order 0 (00)

Number Of Registers Low Order 3 (03)

Error Check (LRC or CRC) --

The response simply echoes the query without returning the

preset values after the register contents have been preset. No

response is returned to broadcast queries from a master device.

Report Slave ID (17)

This command returns the model number, serial number, and

firmware number for the Acromag slave device, the status of the

Run indicator, and any other information specific to the device.

This command does not address Register Map registers.

Broadcast transmission is not supported.

The Report Slave ID query simply sends the slave address

and function code with error check (CRC) as follows:

Report Slave ID Example Query

Field N

ame

Example Value (Hex)

Slave Address 247 (F7)

Function Code 17 (11)

Error Check (LRC or CRC) --

Report Slave ID Example Response (Acromag)

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 17 (11)

Byte Count 26 (1A)

Acromag Slave ID

0(00H)=924MB; 1(01H)=913MB;

2(02H)=914MB; 3(03H)=917MB;

4(04H)=918MB; 5 (05H)=901MB;

6(06H)=902MB; 7(07H)=903MB;

8(08H)=904MB; 9(09H)=905MB;

10(0AH)=906MB.

Run Indicator (ON) 255 (FF)

Firmware Number

ASCII Byte String

(Additional Data

Field)

“ACROMAG,9300-036A, 913MB-

0900,”

(41 43 52 4F 4D 41 47 2C 39 33

30 30 2D 30 33 36 41 2C 39 31

33 4D 42 2D 30 39 30 30 2CH)

Serial Number ASCII

Byte String (Unique

Per Module)

Six Numbers + Revision

“123456A”

(31 32 33 34 35 36 41H)

Error Check

(LRC/CRC) --

Reset Slave (08)

This command is used to trigger a reset of the module and its

effect is equivalent to a power-on reset of the module. Note that

changes to baud rate, slave address, and parity are initiated

following reset. The Reset Slave command uses sub-function 01

(Restart Communications) of the standard Modbus Diagnostics

Command (08) to accomplish a module reset. This function does

not operate on register map locations. Broadcast transmission is

not supported.

The Reset Slave query simply sends the slave address,

function code, sub-function code, and data (data is ignored and

simply echoed back), with error check (CRC). A Reset Slave

response is simply an echoed acknowledge that is returned just

before the reset is executed. Allow a few seconds following reset

to re-initiate communication with a module.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 18 -

Reset Slave Example Query

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 08 (08)

Sub-Function High Order Byte 0 (00)

Sub-Function Low Order Byte 1 (01)

Data Field High-Order Byte 0 (00)

Data Field Low Order Byte 0 (00)

Error Check (LRC or CRC) --

Reset Slave Example Response (Sent Prior To Reset)

Field Name

Example Value (Hex)

Slave Address 247 (F7)

Function Code 08 (08)

Sub-Function High Order Byte 0 (00)

Sub-Function Low Order Byte 1 (01)

Data Field High-Order Byte 0 (00)

Data Field Low Order Byte 0 (00)

Error Check (LRC or CRC) --

For Modbus software that does not support the Reset Slave

function, an alternate method of generating a module reset is

provided via a write to the Calibration Access & Module Reset

Modbus Data Field

The data field of a message frame contains a multiple of 8

bits that provides the slave with any additional information the

slave requires to complete the action specified by the function

code. The data field typically includes register addresses, count

values, and written data. The data field can be nonexistent for

some commands (zero length), as not all messages require data.

If no error occurs, the data field of a response from a slave

will return the requested data. If an error occurs, the data field

returns an exception code (see Modbus Exceptions) that the

master application can use to determine the next action to take.

Supported Data Types

All I/O values are accessed via 16-bit Input Registers or 16-

bit Holding Registers (see Register Map). Input registers contain

information that is read-only. For example, the current input

value read from a channel, or the states of a group of digital

inputs. Holding registers contain read/write information that may

be configuration data or output data. For example, the high limit

value of an alarm function operating at an input, or an output

value for an output channel. I/O values for this model are

represented by the following simple data types for temperature,

percentage, and discrete on/off.

Summary Of Data Types Used By 900MB Modules

Data Types

Description

Count Value A 16-bit signed integer value representing an

A/D count, a DAC count, or a time value with

a range of –32768 to +32767.

Percentage A 16-bit signed integer value with resolution

of 0.005%/lsb. ±20000 is used to represent

±100%. For example, -100%, 0% and

+100% are represented by decimal values –

20000, 0, and 20000, respectively. The full

range is –163.84% (-32768 decimal) to

+163.835% (+32767 decimal).

Summary Of Data Types Used By 900MB Modules..continued

Data Types

Description

Temperature A 16-bit signed integer value with resolution

of 0.1°C/lsb. For example, a value of 12059

is equivalent to 1205.9°C, a value of –187

equals –18.7°C. The maximum possible

temperature range is –3276.8°C to

+3276.7°C.

Discrete A discrete value is generally indicated by a

single bit of a 16-bit word. The bit

number/position typically corresponds to the

discrete channel number for this model.

Unless otherwise defined for outputs, a 1 bit

means the corresponding output is closed or

ON, a 0 bit means the output is open or

OFF. For inputs, a value of 1 means the

input is in its high state (usually >> 0V),

while a value of 0 specifies the input is in its

low state (near 0V).

Modbus Error Checking Fields

Modbus networks employ two methods of error checking:

parity checking (even or odd parity, or none), and frame checking

(Cyclical Redundancy Check).

Parity Checking

A Modbus device can be configured for Even or Odd parity

checking, or for no parity checking, and this determines how the

parity bit of the data frame is set. If even or odd parity checking

is selected, the number of 1 bits in the data portion of each

character frame is counted. Each character in RTU mode

contains 8 bits. The parity bit will then be set to a 0 or a 1, to

result in an even (Even parity), or odd (Odd parity) total number

of 1 bits. For example, if an RTU character frame contains the

following eight data bits: 1100 0011, then since the total number

of 1 bits is 4 (already an even number), the frame’s parity bit will

be 0 if even parity is selected. If odd parity is used, then the

parity bit will be set to 1, making the total number of bits an odd

number (five).

When a message is transmitted, the parity bit is calculated

and applied to the frame of each character transmitted. The

receiving device counts the quantity of 1 bits in the data portion of

the frame and sets an error flag if the count differs from that sent.

As such, parity checking can only detect an error if an odd

number of bits are picked up or dropped off from a character

frame during transmission. For example, if odd parity is

employed and two 1 bits are dropped from a character, the result

is still an odd count of 1 bits. Note that all devices on a Modbus

network must use the same parity. If no parity checking is

selected, then no parity bit is transmitted and no parity check is

made. An additional stop bit is transmitted to fill out the character

frame for the no parity selection.

CRC Error Checking

RTU Mode message frames include an error checking

method that is based on a Cyclical Redundancy Check (CRC).

The error checking field of a frame contains a 16-bit value (two 8-

bit bytes) that contain the result of a Cyclical Redundancy Check

(CRC) calculation performed on the message contents.

BusWorks®Model 913MB/914MB Network I/O Module User’s Manual DC Current/Voltage Input

___________________________________________________________________________________________

- 19 -

The CRC value is calculated by the transmitting device and is

appended to the message as the last field in a message—the low

order byte is appended first, followed by the high-order byte.

Thus, the CRC high-order byte is the last byte to be sent in a

message. The receiving device calculates a CRC during receipt

of a message and compares the calculated value to that received

in the CRC field. If the two values differ, an error results.

The CRC is started by first preloading the 16-bit CRC register

to all 1’s. Successive 8-bit bytes of the message (only the 8-data

bits in each character--no start, stop, or parity bits) are applied to

the current contents of the register, and each 8-bit character is

exclusive OR’ed with the register contents. The exclusive OR

result is shifted in the direction of the least significant bit (lsb) of

the CRC, with a zero placed into the most significant bit (msb).

The lsb is then extracted and examined, if the lsb is a 1, the

a 0, no exclusive OR takes place. This process is repeated until

8 shifts have been performed. After the last (eighth) shift, the

next 8-bit byte is exclusive OR’ed with the register’s current

contents, and the process repeats itself for 8 more shifts as

described above. The final contents of the CRC register after all

the message bytes have been applied is the CRC value.

Modbus Exceptions

If an unsupported function code is sent to a module, then the

exception code 01 (Illegal Function) will be returned in the data

field of the response message. If a holding register is written with

an invalid value, then exception code 03 (Illegal Data Value) will

be returned in the response message. The following table lists

the possible exception codes:

Modbus Exception Codes

Code

Exception

Description

01 Illegal Function The function code received in the

query is not allowed or invalid.

02 Illegal Data

Address

The data address received in the

query is not an allowable address

for the slave or is invalid.

03 Illegal Data

Value

A value contained in the query

data field is not an allowable value

for the slave or is invalid.

04 Slave Device

Failure

An unrecoverable error occurred

while the slave was attempting to

perform the requested action.

05 Acknowledge The slave has accepted the

request and is processing it, but a

long duration of time is required to

do so. This response is returned

to prevent a timeout error from

occurring in the master.

06 Slave Device

Busy

The slave is engaged in

processing a long-duration

program command. The master

should retransmit the message

later when the slave is free.

07 Negative

Acknowledge

The slave cannot perform the

program function received in the

query. This code is returned for

an unsuccessful programming

request using function code 13 or

14 (codes not supported by this

model). The master should

request diagnostic information

from the slave.

Modbus Exception Codes…continued

Code Exception Description

08 Memory Parity

Error

The slave attempted to read

extended memory, but detected a

parity error in memory. The master

can retry the request, but service

may be required at the slave

device.

In a normal response, the slave echoes the function code of

the original query in the function field of the response. All

function codes have their most-significant bit (msb) set to 0 (their

values are below 80H). In an exception response, the slave sets

the msb of the function code to 1 in the returned response (i.e.

exactly 80H higher than normal) and returns the exception code

in the data field. This is used by the master’s application to

recognize an exception response and to direct an examination of

the data field for the applicable exception code.

MODULE SOFTWARE CONFIGURATION

From the factory, each module has a default configuration as

detailed in the INSTALLATION section of this manual. Your

application will likely differ from the default configuration and the

module will need to be reconfigured. Series 900MB modules

may be configured and calibrated by issuing the appropriate

Modbus functions to the Register Map registers, as required to

configure the unit. However, it is much simpler to use the 900MB

Configuration Software to program and control the module

parameters and operating modes. This software is easy to use,

self-explanatory, and complete configuration takes only a few

minutes. On-line help is built-in. As such, a comprehensive

guide to the use of this program is not necessary. To begin

configuration, you should already be familiar with Windows

operation and have a basic understanding of module terminology

as it relates to this model.

Before You Begin

1. Have you installed the 900MB Configuration Program? You

should complete the MODULE INSTALLATION section

(Section 2.0) of this manual before proceeding.

2. Check that all necessary electrical connections have been

made and that power is applied (module’s green LED ON).

3. Is baud set correctly at the RS485 converter/repeater??

4. Have you tried communicating using the Default Mode?

Press the “DFT” push-button of the 913MB/914MB module

until the yellow status LED is flashing. This sets the

module’s communication parameters to 9600 baud, a slave

address of 247, no parity, and one or two stop bits.

5. If you fail to communicate with the module or have a high

degree of communication errors, try increasing the response

delay time (See Response Delay Register 40006). Some

network converters or host/software systems cannot accept

an immediate response from a slave without added delay.

6. Do not leave unused inputs floating, or you may experience

increased measurement noise and slower update cycles. It

is recommended that unused inputs be shorted by applying

a jumper between IN+ and IN-.

The following sections guide you through the 900MB

Configuration Program property sheets used to configure a

914MB-0900 Transmitter. The model 913MB-0900 is similar.

Property sheets will vary somewhat from model to model, but the

general approach is the same.

Other manuals for BusWorks 900MB Series

This manual suits for next models

Table of contents

Other Acromag Control Unit manuals

Acromag

Acromag BusWorks XT Series User manual

Acromag

Acromag APMC4110 User manual

Acromag

Acromag BusWorks 900EN Series User manual

Acromag

Acromag 611T Series User manual

Acromag

Acromag BusWorks XT Series User manual

Acromag

Acromag IOS-521 Series User manual

Acromag

Acromag IP511 Series User manual

Acromag

Acromag BusWorks XT Series User manual

Acromag

Acromag XVME-6700A User manual

Acromag

Acromag AcroPack AP513 User manual

Acromag

Acromag BusWorks 900MB Series User manual

Acromag

Acromag XVME-6500 User manual

Acromag

Acromag EtherStax Series User manual

Acromag

Acromag PMC230 Series User manual

Acromag

Acromag AcroPack Series User manual

Acromag

Acromag BusWorks 900EN Series User manual

Acromag

Acromag VPX4810 User manual

Acromag

Acromag AcroPack AP580E-LF User manual

Acromag

Acromag AcroPack AP48 Series User manual

Acromag

Acromag BusWorks 900EN Series User manual

Acromag

Acromag APZU AcroPack Series User manual

Acromag

Acromag BusWorks 900EN Series User manual

Acromag

Acromag Intel 4 XVME-6500A User manual

Acromag

Acromag AcroPack AP471 Series User manual

Popular Control Unit manuals by other brands

Velleman

Velleman K2636 Illustrated assembly manual

GEM

GEM 649 eSyDrive operating instructions

National Instruments

National Instruments PXI-6683 Series user manual

Harvia

Harvia XENIO CX170 Instructions for use

elero

elero VarioTec operating instructions

Comparato

Comparato NELLO DIAMANT 2000 instruction manual

Yolink

Yolink YS5002-UC Installation & user guide

Duemmegi

Duemmegi Domino DFANA-M quick start guide

Bailey

Bailey Infi 90 NTAI04 Instruction

Siemens

Siemens SINAMICS S120 manual

Stafer

Stafer V6RX.E3 User and maintenance manual

Sanhua

Sanhua MDF Series instructions

ABNOX

ABNOX AXDV-C3-HG Instructions for use

Siemens

Siemens SINUMERIK 840C Operator's guide

Abicor Binzel

Abicor Binzel ROBiPAK Assembly instructions

TECH

TECH ST-65 user manual

Moen

Moen DURA-GRIP 4792 installation guide

Pentair

Pentair FLECK PROFLOSXT DOWNFLOW Service manual