Sierra InnovaMass 240 series User manual

240/241 Series Modbus
Instruction Manual
Modbus Device Specification for Models:
240-V, -VT, -VTP, -LP & 241-V, -VT, -VTP, -LP
Multivariable Mass Vortex Flow Meters
Part Number: IM240/241 Modbus, Rev. V1
May 2013

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Phone: + 8621 5879 8521 Fax: [phone]
IMPORTANT CUSTOMER NOTICE- OXYGEN SERVICE
Sierra Instruments, Inc. is not liable for any damage or personal injury, whatsoever, resulting from the use of Sierra Instruments
standard mass flow meters for oxygen gas. You are responsible for determining if this mass flow meter is appropriate for your
oxygen application. You are responsible for cleaning the mass flow meter to the degree required for your oxygen flow
application.
© COPYRIGHT SIERRA INSTRUMENTS 2012
No part of this publication may be copied or distributed, transmitted, transcribed, stored in a retrieval system, or translated
into any human or computer language, in any form or by any means, electronic, mechanical, manual, or otherwise, or
disclosed to third parties without the express written permission of Sierra Instruments. The information contained in this
manual is subject to change without notice.
TRADEMARKS
InnovaFlo®and InnovaMass®are trademarks of Sierra Instruments, Inc. Other product and company names listed in this
manual are trademarks or trade names of their respective manufacturers.

Warnings and Cautions
Warning! Agency approval for hazardous location installations varies between flow meter models. Consult the flow meter
nameplate for specific flow meter approvals before any hazardous location installation.
Warning! Hot tapping must be performed by a trained professional. U.S. regulations often require a hot tap permit. The
manufacturer of the hot tap equipment and/or the contractor performing the hot tap is responsible for providing proof of such a
permit.
Warning! All wiring procedures must be performed with the power off.
Warning! To avoid potential electric shock, follow National Electric Code safety practices or your local code when wiring this unit
to a power source and to peripheral devices. Failure to do so could result in injury or death. All AC power connections must be in
accordance with published CE directives.
Warning! Do not power the flow meter with the sensor remote (if applicable) wires disconnected. This could cause over-heating of the
sensors and/or damage to the electronics.
Warning! Before attempting any flow meter repair, verify that the line is de-pressurized.
Warning! Always remove main power before disassembling any part of the mass flow meter.
Caution! Before making adjustments to the device, verify the flow meter is not actively monitoring or reporting to any master
control system. Adjustments to the electronics will cause direct changes to flow control settings.
Caution! All flow meter connections, isolation valves and fittings for hot tapping must have the same or higher pressure rating
as the main pipeline.
Caution! Changing the length of cables or interchanging sensors or sensor wiring will affect the accuracy of the flow meter.
You cannot add or subtract wire length without returning the meter to the factory for re-calibration.
Caution! When using toxic or corrosive gases, purge the line with inert gas for a minimum of four hours at full gas flow
before installing the meter.
Caution! The AC wire insulation temperature rating must meet or exceed 80°C (176°F).
Caution! Printed circuit boards are sensitive to electrostatic discharge. To avoid damaging the board, follow these
precautions to minimize the risk of damage:
before handling the assembly, discharge your body by touching a grounded, metal object
handle all cards by their edges unless otherwise required
when possible, use grounded electrostatic discharge wrist straps when handling sensitive components
!


4
Note and Safety Information
We use caution and warning statements throughout this book to draw your attention to important
information.
Warning!
Caution!
This statement appears with information that
is important to protect people and equipment
from damage. Pay very close attention to all
warnings that apply to your application.
This statement appears with information that is
important for protecting your equipment and
performance. Read and follow all cautions that
apply to your application.
Receipt of System Components
When receiving a Sierra mass flow meter, carefully check the outside packing carton for damage
incurred in shipment. If the carton is damaged, notify the local carrier and submit a report to the
factory or distributor. Remove the packing slip and check that all ordered components are present.
Make sure any spare parts or accessories are not discarded with the packing material. Do not
return any equipment to the factory without first contacting Sierra Customer Service .
Technical Assistance
If you encounter a problem with your flow meter, review the configuration information for each
step of the installation, operation, and setup procedures. Verify that your settings and adjustments
are consistent with factory recommendations. Installation and troubleshooting information can be
found in the 240/241 Series Product Instruction Manual.
If the problem persists after following the troubleshooting procedures outlined in the 640S or 780S
product manuals, contact Sierra Instruments by fax or by E-mail (see inside front cover). For
urgent phone support you may call [phone] or [phone] between 8:00 a.m. and 5:00
p.m. PST. In Europe, contact Sierra Instruments Europe at [phone]. In the Asia-Pacific
region, contact Sierra Instruments Asia at + 86-21-58798521. When contacting Technical Support,
make sure to include this information:
 The flow range, serial number, and Sierra order number (all marked on the meter
nameplate)
 The software version (visible at start up)
 The problem you are encountering and any corrective action taken
 Application information (gas, pressure, temperature and piping configuration)
!


5
Table of Contents
T
Table of Contents .................................................................................................................... …….5
Chapter 1: Modbus Communications….........................................................................................6
Applicable Flow Meter Models................................................................................................................................... 6
Wiring......................................................................................................................................................................... 6
Pin Labeling (among devices).................................................................................................................................... 7
Menu Items................................................................................................................................................................ 7
Address...................................................................................................................................................................... 7
Comm Protocol.......................................................................................................................................................... 7
Modbus Units............................................................................................................................................................. 8
Modbus Order............................................................................................................................................................ 8
Modbus Protocol........................................................................................................................................................ 8
Register Definitions.................................................................................................................................................... 9
Exception Status Definitions .................................................................................................................................... 11
Discrete Input Definitions......................................................................................................................................... 11
Control Register Definitions ..................................................................................................................................... 11
Error Responses...................................................................................................................................................... 11
Command Message Format .................................................................................................................................... 12
Normal Response Message Format ........................................................................................................................ 12
Exception Response Message Format.................................................................................................................... 12
Examples................................................................................................................................................................. 12

6
Chapter 1: Modbus Communications
Applicable Flow Meter Models
Sierra’s InnovaMass®240 and 241 Mass Vortex Flow Meters with Modbus communication protocol and
firmware version 4.00.58 and above.
Overview
This document describes the implementation of the Modbus communication protocol
for use in monitoring common process variables in the Sierra InnovaMass Vortex
flow meter. The physical layer utilizes the half-duplex RS-485 port, and the Modbus
protocol.
Reference Documents
The following documents are available online from www.modbus.org.
Modbus Application Protocol Specification V1.1 b3
Modbus Over Serial Line Specification & Implementation Guide V1.0 2
Modicon Modbus Protocol Reference Guide PI–MBUS–300 Rev. J
Wiring
An RS485 daisy chained network configuration as depicted below is recommended. Do not use a star, ring, or
cluster arrangement. Consult your RS-485 master’s documentation about the need for termination, pull-up and
pull-down resistors.
RS-485 -
RS-485 +
RS-485 GND
RS-485 Master
Vortex Meter
RS-485 -
RS-485 +
RS-485 GND
RS-485 -
RS-485 +
RS-485 GND
Other Device 2, etc.
RS-485 -
RS-485 +
RS-485 GND
Other Device 1
Figure 1: RS-485 Wiring (Modbus)
Warning!
Place controls in manual
mode when making
configuration changes to
the instrument.

7
Pin Labeling (among devices)
“RS-485 –” = “A” = “TxD-/RxD-” = “Inverting pin”
“RS-485 +” = “B” = “TxD+/RxD+” = “Non-Inverting pin”
“RS-485 GND” = “GND” = “G” = “SC” = “Reference”
4-20
mA 3
4-20
mA 1
DC
PWR
+ - +
4-20
mA 2
- + - +
RS485
RS485
RS485 GND
-
OPTION 2
+
ALARM
2
PULSE
OUT
FREQ
OUT
+ - +
ALARM
1
-+ -
4
OPTION 1
1 2 3 15 2 3
ALARM
3
- + -
4 5
+
-
Figure 1: DC Wiring Terminals
Menu Items
The following menu items are in the display, DD option Output Menu and allow selection and control of
the Modbus communication protocol.
Address
When the Modbus protocol is selected, the Modbus address is equal to the user programmable device address
if it is in the range 1…247, in accordance with the Modbus specification. If the device address is zero or is
greater than 247, then the Modbus address is internally set to 1.
Comm Protocol
The Comm Protocol menu allows selection of “Modbus RTU Even,” “Modbus RTU Odd,” or “Modbus
RTU None2,” or “Modbus RTU None1,” (non-standard Modbus) with Even, Odd and None referring to
the parity selection. When even or odd parity is selected, the unit is configured for 8 data bits, 1 parity
bit and 1 stop bit; with no parity, the number of stop bits is 1 (non-standard) or 2. When changing the
240/241 Pins
Rs485 Labeling
Synonyms
RS485 -
A, TxD-/RxD-,
Inverting pin
RS485 +
B, TxD+/RxD+,
Non-Inverting pin
RS485 GND
GND, G, SC,
Reference

8
protocol, the change is made as soon as the Enter key is pressed.
Modbus Units
The Modbus Units menu is to control what units, where applicable, the meter’s variables will be displayed in.
Internal –these are the base units of the meter, °F, psia, lbm/sec , ft
3
/sec, Btu/sec , lbm/ft
3
Display –variables
are displayed in user selected display unit.
Modbus Order
The byte order within registers and the order in which multiple registers containing floating point or long
integer data are transmitted may be changed with this menu item. According to the Modbus specification, the
most significant byte of a register is transmitted first, followed by the least significant byte. The Modbus
specification does not prescribe the order in which registers are transmitted when multiple registers represent
values longer than 16 bits. Using this menu item, the order in which registers representing floating point or
long integer data and/or the byte order within the registers may be reversed for compatibility with some PLCs
and PC software.
The following four selections are available in this menu; when selecting an item, the protocol is changed
immediately without having to press the Enter key.
0-1:2-3
Most significant register first, most significant byte first (default)
2-3:0-1
Least significant register first, most significant byte first
1-0:3-2
Most significant register first, least significant byte first
3-2:1-0
Least significant register first, least significant byte first
Note that all of the registers are affected by the byte order, including strings and registers representing 16-bit
integers; the register order only affects the order of those registers representing 32-bit floating point and long
integer data, but does not affect single 16-bit integers or strings.
Modbus Protocol
The Modbus RTU protocol is supported in this implementation. Supported baud rates are 1200, 2400, 4800,
9600, 19200, 38400, 57600, and 115200. The default baud rate is 19200 baud. Depending upon the Modbus
protocol selected, data are transmitted in 8-bit data frames with even or odd parity and 1 stop bit, or no parity
and 2 or 1 (non-standard) stop bits.
The current Modbus protocol specification does not define register usage, but there is an informal register
numbering convention derived from the original (now obsolete) Modicon Modbus protocol specification, and
used by many vendors of Modbus capable products.
Registers
Usage
Valid Function Codes
00001–09999
Read/write bits ("coils")
01 (read coils) 05 (write single coil)
15 (write multiple coils)
10001–19999
Read-only bits ("discrete inputs")
02 (read discrete inputs)

9
Each range of register numbers maps to a unique range of addresses that are determined by the function code
and the register number. The address is equal to the least significant four digits of the register number minus
one, as shown in the following table.
Registers
Function Codes
Data Type and Address Range
00001-09999
01, 05, 15
Read/write bits 0000-9998
10001-19999
02
Read-only bits 0000-9999
30001-39999
03, 04
Read-only 16-bit registers 0000-9998
40001-49999
03, 06, 16
Read/write 16-bit registers 0000-9998
Register Definitions
The meter serial number and those variables that are commonly monitored (mass, volume and energy flow
rates, total, pressure, temperature, density, viscosity, Reynolds number, and diagnostic variables such as
frequency, velocity, gain, amplitude and filter setting) are accessible via the Modbus protocol. Long integer
and floating point numbers are accessed as pairs of 16-bit registers in the register order selected in the Modbus
Order menu. Floating point numbers are formatted as single precision IEEE 754 floating point values.
The flow rate, temperature, pressure, and density variables may be accessed as either the flow meter internal
base units or in the user-programmed display units, which is determined by the programming of the display,
DD option Output Menu’s “Modbus Units” item. The display units strings may be examined by accessing
their associated registers. Each of these units string registers contain 2 characters of the string, and the strings
may be 2 to 12 characters in length with unused characters set to zero. Note that the byte order affects the
order in which the strings are transmitted. If the Modbus Order menu (see page 2) is set to 0-1:2-3 or 2-3:0-1,
then the characters are transmitted in the correct order; if set to 1-0:3-2 or 3-2:1-0, then each pair of
characters will be transmitted in reverse order.
30001–39999
Read-only 16 bit registers ("input
registers"), IEEE 754 floating point
register pairs, arbitrary length strings
encoded as two ASCII characters per 16-
bit register
03 (read holding registers) 04 (read
input registers)
40001–49999
Read/write 16-bit registers ("holding
registers"), IEEE 754 floating point
register pairs, arbitrary length strings
encoded as two ASCII characters per 16-
bit register
03 (read holding registers) 06 (write
single register) 16 (write multiple
registers)

10
Registers
Variable
Data Type
Units
Function
Code
Addresses
65100-65101
Serial number
unsigned long
—
03, 04
30525-30526
Totalizer
unsigned long
display units*
03, 04
524-525
32037-32042
Totalizer units
string
—
03, 04
2036-2041
30009-30010
Mass flow
float
display units*
03, 04
8-9
30007-30008
Volume flow
float
display units*
03, 04
6-7
30005-30006
Pressure
float
display units*
03, 04
4-5
30001-30002
Temperature
float
display units*
03, 04
0-1
30029-30030
Velocity
float
ft/sec
03, 04
28-29
30015-30016
Density
float
display units*
03, 04
14-15
30013-30014
Viscosity
float
cP
03, 04
12-13
30031-30032
Reynolds number
float
—
03, 04
30-31
30025-30026
Vortex frequency
float
Hz
03, 04
24-25
34532
Gain
char
—
03, 04
4531
30085-30086
Vortex amplitude
float
Vrms
03, 04
84-85
30027-30028
Filter setting
float
Hz
03, 04
26-27
The following registers are available with the energy meter firmware:
Registers
Variable
Data Type
Units
Function
Code
Addresses
30527-30528
Totalizer #2
unsigned long
display units*
03, 04
526-527
32043-32048
Totalizer #2 units
string
—
03, 04
2042-2047
30003-30004
Temperature #2
float
display units*
03, 04
2-3
30011-30012
Energy flow
float
display units*
03, 04
10-11
The following registers contain the display units strings:
Registers
Variable
Data Type
Units
Function Code
Addresses
32007-32012
Volume flow units
string
—
03, 04
2006-2011
32001-32006
Mass flow units
string
—
03, 04
2000-2005
32025-32030
Temperature units
string
—
03, 04
2024-2029
32019-32024
Pressure units
string
—
03, 04
2018-2023
32031-32036
Density units
string
—
03, 04
2030-2035
32013-32017
Energy flow units
string
—
03, 04
2012-2017
Function codes 03 (read holding registers) and 04 (read input registers) are the only codes supported for
reading these registers, and function codes for writing holding registers are not implemented. We recommend
that the floating point and long integer registers be read in a single operation with the number of registers
being a multiple of two. If these data are read in two separate operations, each reading a single 16-bit register,
then the value will likely be invalid.
The floating point registers with values in display units are scaled to the same units as are displayed, but are
instantaneous values that are not smoothed. If display smoothing is enabled (non-zero value entered in the

11
Display TC item in the Display Menu), then the register values will not agree exactly with the displayed
values.
Exception Status Definitions
The Read Exception Status command (function code 07) returns the exception status byte, which is defined as
follows. This byte may be cleared by setting “coil” register #00003 (function code 5, address 2, data = 0xff00).
Bit(s)
Definition
0-1
Byte order (see Modbus Order on page 2)
0 = 3-2:1-0 1 = 2-3:0-1
2 = 1-0:3-2 3 = 0-1:2-3
2
Temperature sensor fault
3
Pressure sensor fault
4
A/D converter fault
5
Period overflow
6
Pulse overflow
7
Configuration changed
Discrete Input Definitions
The status of the three alarms may be monitored via the Modbus Read Discrete Input command (function code
02). The value returned indicates the state of the alarm, and will be 1 only if the alarm is enabled and active. A
zero value is transmitted for alarms that are either disabled or inactive,
Registers
Variable
Function Code
Address
10001
Alarm #1 state
02
0
10002
Alarm #2 state
02
1
10003
Alarm #3 state
02
2
Control Register Definitions
The only writeable registers in this implementation are the Reset Exception Status, Reset Meter and Reset
Totalizer functions, which are implemented as ”coils” which may be written with the Write Single Coil
command (function code 05) to address 8 through 10, respectively, (register #00009 through #00011). The
value sent with this command must be either 0x0000 or 0xff00, or the meter will respond with an error
message; the totalizer will be reset or exception status cleared only with a value of 0xff00.
Error Responses
If an error is detected in the message received by the unit, the function code in the response is the received
function code with the most significant bit set, and the data field will contain the exception code byte, as
follows:
Exception
Code
Description
01
Invalid function code —function code not supported by device
02
Invalid data address —address defined by the start address and number of registers
is out of range
03
Invalid data value —number of registers = 0 or >125 or incorrect data with the Write
Single Coil command

12
If the first byte of a message is not equal to the unit’s Modbus address, if the unit detects a parity error in any
character in the received message (with even or odd parity enabled), or if the message CRC is incorrect, the
unit will not respond.
Command Message Format
The start address is equal to the desired first register number minus one. The addresses derived from the start
address and the number of registers must all be mapped to valid defined registers, or an invalid data address
exception will occur.
Normal Response Message Format
Exception Response Message Format
Examples
Read the exception status byte from the device with address 1:
01 07 41 E2
01 Device address
07 Function code, 04 = read exception status
A typical response from the device is as follows:
01 07 03 62 31
01 Device address
07 Function code
03 Exception status byte
62 31 CRC
Request the first 12 registers from device with address 1:
01 04 00 00 00 0C F0 0F
01 Device address
04 Function code, 04 = read input register
00 00 Starting address
00 0C Number of registers = 12
F0 0F CRC

13
A typical response from the device is as follows: *note these are the older register definitions
01 04 18 00 00 03 E8 00 00 7A 02 6C 62 00 00 41 BA 87 F2 3E BF FC 6F 42 12 EC 8B 4D D1
01 Device address
04 Function code
18 Number of data bytes = 24
00 00 03 E8 Serial number = 1000 (unsigned long)
00 00 7A 02 Totalizer = 31234 lbm (unsigned long)
6C 62 00 00 Totalizer units = “lb” (string, unused characters are 0)
41 BA 87 F2 Mass flow rate = 23.3164 lbm/sec (float)
3E BF FC 6F Volume flow rate = 0.3750 ft
3
/sec (float)
42 12 EC 8B Pressure = 36.731 psia (float)
4D D1 CRC
An attempt to read register(s) that don’t exist
01 04 00 00 00 50 F1 D2
01 Device address
04 Function code 4 = read input register
00 00 Starting address
00 50 Number of registers = 80
F0 36 CRC
results in an error response as follows:
01 84 02 C2 C1
01 Device address
84 Function code with most significant bit set indicates error response
02 Exception code 2 = invalid data address
C2 C1 CRC
Request the state all three alarms:
01 02 00 00 00 03 38 0B
01 Device address
02 Function code 2 = read discrete inputs
00 00 Starting address
00 03 Number of inputs = 3
38 0B CRC
and the unit responds with:
01 02 01 02 20 49
01 Device address
02 Function code
01 Number of data bytes = 1
02 Alarm #2 on, alarms #1 and #3 off
20 49 CRC
To reset the totalizer:
01 05 00 00 FF 00 8C 3A

14
01 Device address
05 Function code 5 = write single coil
00 09 Coil address = 9
FF 00 Data to reset totalizer
8C 3A CRC (not the correct CRC EJS-02-06-07)
The unit responds with an identical message to that transmitted, and the totalizer is reset. If the “coil” is turned
off as in the following message, the response is also identical to the transmitted message, but the totalizer is
not affected.
01 05 00 00 00 00 CD CA
01 Device address
05 Function code 5 = write single coil
00 00 Coil address = 0
00 00 Data to “turn off coil” does not reset totalizer
CD CA CRC