Allen-Bradley SLC 500 User manual

User
Manual
SLC 500™
Thermocouple/mV
Analog Input Module
(Catalog Number 1746-NT8)
Allen-Bradley

Important User Information Because of the variety of uses for the products described in this publication,
those responsible for the application and use of this control equipment must
satisfy themselves that all necessary steps have been taken to assure that
each application and use meets all performance and safety requirements,
including any applicable laws, regulations, codes and standards.
The illustrations, charts, sample programs and layout examples shown in
this guide are intended solely for purposes of example. Since there are many
variables and requirements associated with any particular installation,
Allen-Bradley does not assume responsibility or liability (to include
intellectual property liability) for actual use based upon the examples shown
in this publication.
Allen-Bradley publication SGI-1.1, Safety Guidelines for the Application,
Installation and Maintenance of Solid-State Control (available from your
local Allen-Bradley office), describes some important differences between
solid-state equipment and electromechanical devices that should be taken
into consideration when applying products such as those described in this
publication.
Reproduction of the contents of this copyrighted publication, in whole or
part, without written permission of Rockwell Automation, is prohibited.
Throughout this manual we use notes to make you aware of safety
considerations:
Attention statements help you to:
•identify a hazard
•avoid a hazard
•recognize the consequences
Important:Identifies information that is critical for successful application
and understanding of the product.
PLC, PLC-2, PLC-3, and PLC-5 are registered trademarks of Rockwell Automation. SLC, SLC 500, SLC 5/01, SLC 5/02, SLC 5/03, SLC
5/04, and SLC 5/05 are registered trademarks of Rockwell Automation. Belden is a trademark of Belden, Inc.
!
ATTENTION: Identifies information about practices or
circumstances that can lead to personal injury or death,
property damage or economic loss

Publication 1746-6.22
Table of Contents
Preface Who ShouldUse This Manual . . . . . .. . . . . . . . .. . . . . . . . . .P-1
What This Manual Covers . . . . . .. . . . . . . . . .. . . . . . . . .. . . P-1
Related Allen-Bradley Documents . . . . . . .. . . . . . . . . .. . . . .P-2
Common Techniques Used in thisManual . . . . . . . . . . .. . . . .P-3
Allen-Bradley Support . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . .P-3
Local Product Support . . . . .. . . . . . . . . . . .. . . . . . . . .. . .P-3
Technical Product Assistance . . . . . .. . . . . . . . . .. . . . . . .P-3
Your Questions or Comments on this Manual. . . .. . . . . . .P-3
Module Overview Chapter 1
General Description . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . 1-1
Input Ranges . . . . . . .. . . . . . . . . .. . . . . . . . . . . .. . . . . . . 1-1
Hardware Features . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . 1-2
Diagnostic LEDs . .. . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . 1-3
System Overview . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . .. . . 1-3
System Operation .. . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . 1-3
Module Operation .. . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . 1-4
Module Addressing . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . 1-4
Block Diagram . . . . . .. . . . . . . . . .. . . . . . . . . . . .. . . . . . . 1-5
Linear Millivolt Device Compatibility. . . . . . .. . . . . . . . . . . . 1-6
Installing And Wiring
Your Module Chapter 2
Electrostatic Damage . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . 2-1
Power Requirements . . . . . .. . . . . . .. . . . . . . . .. . . . . . . . . . 2-2
Considerations for a Modular System. . . . . . . .. . . . . . . 2-2
Fixed I/O Chassis - I/O ModuleCompatibility. . . . . .. . . 2-3
General Considerations . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . 2-4
Module Installation andRemoval . . . . . .. . . . . . . . . .. . . . . . . 2-5
Terminal BlockRemoval.. . . . . . .. . . . . . . . . .. . . . . . . 2-6
Wiring Your Module . .. . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . 2-7
Preparing and Wiringthe Cables . . .. . . . . . . . . .. . . . . 2-8
Cold-Junction Compensation (CJC). .. . . . . . . . . . . .. . . . 2-10

ii Table of Contents
Publication 1746-6.22
Things To Consider
Before Using
Your Module Chapter 3
Module ID Code . . . . . . . . . .. . . . . . . . .. . . . . . .. . . . . . .3-1
Module Addressing . . . . .. . . . . . . . . .. . . . . . .. . . . . . . . .3-2
Output Image -Configuration Words. . .. . . . . . . . . .. .3-2
Input Image -Data Words and Status
Words. . . . . . . . .. . . . . . . . .. . . . . . . . . . . .. . . . . . .3-3
Channel Filter Frequency Selection . . . .. . . . . . . . . .. . . .3-3
Channel Cut-Off Frequency. . .. . . . . . . . . . . .. . . . . . .3-4
Channel Step Response . . . . .. . . . . . . . . .. . . . . . . . .3-6
Update Time .. . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . .3-7
Update Time Calculation Example. . . . .. . . . . . . . . . . .3-7
Channel Turn-On, Turn-Off, and Reconfiguration
Times . . . . . .. . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . .3-8
Auto-Calibration . . .. . . . . . . . . . .. . . . . . . . . .. . . . . . . . .3-8
Response to Slot Disabling . . . . .. . . . . . . . . .. . . . . . . . .3-9
Input Response . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . .3-9
Output Response. .. . . . . . . . .. . . . . . . . . .. . . . . . . . .3-9
Channel Configuration,
Data, and Status Chapter 4
Channel Configuration . . . . . . .. . . . . . . . .. . . . . . . . . . . .4-1
Channel Configuration Procedure . . . . .. . . . . . . . . . . .. .4-2
Select Channel Enable (Bit 0) . . . . . . . . . . . . . . . . . . . .4-5
Select Input Types (Bits 1 through 4). . . . . .. . . . . . . . .4-5
Select DataFormat (Bits 5 and 6) . . . . .. . . . . . . . . .. .4-5
Using Scaled-for-PID and
Proportional Counts. . . . . . .. . . . . . . . . .. . . . . . . . .4-6
Effective Resolutions .. . . . . . . . . . .. . . . . . . . . .. .4-6
ScalingExamples. . . .. . . . . . . . .. . . . . . . . . .. . . .4-7
Select Open-Circuit State (Bits 7 and 8) . . . . . . . . . . . .4-9
Select Temperature Units (Bit 9) . . . . . . . . .. . . . . . . .4-10
Select Channel Filter Frequency
(Bits 10 and11) . . . . . .. . . . . . . . . . .. . . . . . . . . ..4-10
Unused Bits (Bits 12 through 14) . . . . . . . . . . .. . . 4-11
Select Input Image Type (Bit 15) . . . . . . . . . . . . . . 4-11
Channel Data/Status Word . . . . . . . . .. . . . . . . . .. . . . . .4-12
Channel Status Checking . . . . . . .. . . . . . . . . .. . . . . . . .4-12
Channel Status (Bit 0). . . . . . . .. . . . . . . . .. . . . . .4-14
Input TypeStatus (Bits 1 through4). . . . . . . . .. . .4-14
Data Format Type Status (Bits 5 and 6) . . . . . . . . .4-14
Open-Circuit TypeStatus (Bits 7and 8). . . . . .. . .4-14
Temperature Units Type Status (Bit 9) . . . . . . .. . .4-14

Table of Contents iii
Publication 1746-6.22
Channel Filter Frequency
(Bits 10 and 11) . . . . . . .. . . . . . . . .. . . . . . . . . 4-14
Open-Circuit Error (Bit 12) .. . . . . . . . . . . .. . . . . . 4-14
Under-Range Error (Bit 13) . . . . . . .. . . . . . . . .. . 4-15
Over-Range Error (Bit 14) . . .. . . . . . . . . .. . . . . . 4-15
Channel Error (Bit 15) . . . . . .. . . . . . . . . . . .. . . . 4-15
Programming Examples Chapter 5
Basic Example . . . . . . . .. . . . . . .. . . . . . . . .. . . . . . . . . . 5-1
Procedure . . . . . . . . .. . . . . . . . .. . . . . . .. . . . . . . . . . 5-2
Automatic Monitoring Thermocouples
and CJCSensors . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . 5-3
VerifyingChannel Configuration Changes . . . . . .. . . . . . . 5-3
Interfacingto the PID Instruction . . . . . . . .. . . . . . . . .. . . 5-7
Monitoring Channel Status Bits . . . . . .. . . . . . . . . .. . . . . 5-8
PLC 5 Example with NT8 in Remote I/O Rack . . . .. . . . 5-14
Troubleshooting
Your Module Chapter 6
Module andChannel Diagnostics . . . . . . . . . . . .. . . . . . . 6-1
Module Diagnostics at Powerup . . . . . .. . . . . . . . .. . . 6-1
Channel Diagnostics . . .. . . . . . . . .. . . . . . . . . .. . . . . 6-1
LED Indicators . . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . 6-2
LED Troubleshooting Tables. .. . . . . . . . . . . .. . . . . . . 6-2
Channel-statusLEDs (Green). . . . . . . .. . . . . . . . .. . . 6-3
Open-circuitDetection (Bit 12) . . . .. . . . . . . . . .. . . . . 6-3
Out-of-Range Detection (Bit 13 for Under Range,
bit 14 for Over Range) . . . . . .. . . . . . . . . .. . . . . . . 6-3
Channel Error (Bit 15) . .. . . . . . .. . . . . . . . . .. . . . . . . 6-4
Module Status LED (Green) . . . . . .. . . . . . . . . .. . . . . 6-4
Interpreting I/OError Codes . . . .. . . . . . . . . . . .. . . . . . . 6-4
Maintaining Your
Module And Safety
Considerations Chapter 7
Preventive Maintenance . . . . . . .. . . . . . . . .. . . . . . . . . . 7-1
Safety Considerations . . . . . . . . .. . . . . . . . .. . . . . . . . . . 7-1

iv Table of Contents
Publication 1746-6.22
Module Specifications Appendix A
Electrical Specifications . . . . . . . .. . . . . . . . . .. . . . . . . . .A-1
Physical Specifications . . . . .. . . . . . . . . . .. . . . . . . . . .. .A-1
Environmental Specifications . . . . . . . . .. . . . . . .. . . . . . .A-2
Input Specifications . . . . . . .. . . . . . . . .. . . . . . . . . .. . . .A-2
Overall Accuracy . . . .. . . . . . . . . .. . . . . . . . .. . . . . . .A-2
Millivolt. . . . . . . .. . . . . . . . .. . . . . . .. . . . . . . . . .. . . .A-3
Thermocouple . . . . . . . . .. . . . . . . . .. . . . . . . . . .. . . .A-5
Using Grounded Junction,
Ungrounded Junction,
and Exposed Junction
Thermocouples Appendix B
Thermocouple Types . . . . . . . .. . . . . . .. . . . . . . . . .. . . .B-1
GroundedJunction . . . . .. . . . . . . . .. . . . . . . . . .. .B-2
Ungrounded (Insulated) Junction . . . . . .. . . . . . . . .B-2
Exposed Junction. . . . . .. . . . . . . . . . . .. . . . . . . . .B-2
Isolation . . . .. . . . . . . . .. . . . . . . . . . . .. . . . . . . . . .. . . .B-2
GroundedJunction Thermocouples. . . . . . . . .. . . . . . .B-3
Exposed Junction Thermocouples. . . . . . . . . .. . . . . . .B-4
Glossary
Index

Publication 1746-6.22
Preface
Read this preface to familiarize yourself with this user manual. This
preface covers:
• who should use this manual
• what this manual provides
• related Allen-Bradley documents
• common techniques used in this manual
• Allen-Bradley support
Who Should Use This
Manual Use this manual if you design, install, program, or maintain a control
system that uses Allen-Bradley Small Logic Controllers (SLC).
You should have a basic understanding of SLC 500 products. You
should also understand electronic process control and the ladder
program instructions required to generate the electronic signals that
control your application. If you do not, contact your local Allen-
Bradley representative for the proper training before using these
products.
What This Manual
Covers This manual covers the 1746-NT8 thermocouple/millivolt analog
input module. It contains the information you need to install, wire,
use, and maintain these modules. It also provides diagnostic and
troubleshooting help should the need arise.

P-2 Preface
Publication 1746-6.22
Related Allen-Bradley
Documents The following table lists several Allen-Bradley documents that may
help you as you use these products.
To obtain a copy of any of the Allen-Bradley documents listed,
contact your local Allen-Bradley office or distributor.
Publication Number Title
1747-2.30 SLC 500 System Overview
SGI-1.1 Application Considerations for Solid State Controls
1770-4.1 Allen-Bradley Programmable Controller Grounding and
Wiring Guidelines
1747-6.2 Installation & Operation Manual for Modular Hardware Style
Programmable Controllers
1747-6.21 Installation & Operation Manual for Fixed Hardware Style
Programmable Controllers
1747-6.15 SLC 500 Instruction Set Reference Manual
ABT-1747-TSG001 SLC 500 Software Programmers’s Quick Reference Guide
1747-NP002 Allen-Bradley HHT (Hand-Held Terminal) User Manual
1747-NM009 Getting Started Guide for HHT (Hand-Held Terminal)
SD499 Allen-Bradley Publication Index
AG-7.1 Allen-Bradley Industrial Automation Glossary

Preface P-3
Publication 1746-6.22
Common Techniques
Used in this Manual The following conventions are used throughout this manual:
• Bulleted lists such as this one provide information, not
procedural steps.
• Numbered lists provide sequential steps or hierarchical
information.
• Text in this font indicates words or phrases you should type.
• Key names appear in bold, capital letters within brackets (for
example, [ENTER]).
Allen-Bradley Support Allen-Bradley offers support services worldwide, with over 75 Sales/
Support Offices, 512 authorized Distributors and 260 authorized
Systems Integrators located throughout the United States alone, plus
Allen-Bradley representatives in every major country in the world.
Local Product Support
Contact your local Allen-Bradley representative for:
• sales and order support
• product technical training
• warranty support
• support service agreements
Technical Product Assistance
If you need to contact Allen-Bradley for technical assistance, please
review the information in the Troubleshooting chapter first. Then call
your local Allen-Bradley representative.
Your Questions or Comments on this Manual
If you find a problem with this manual, please notify us of it on the
enclosed Publication Problem Report.
If you have any suggestions for how this manual could be made more
useful to you, please contact us at the address below:
Allen-Bradley
Control and Information Group
Technical Communication, Dept. A602V, T122
P.O. Box 2086
Milwaukee, WI 53201–2086

Publication 1746-6.22
Chapter 1
Module Overview
This chapter describes the thermocouple/mv input module and
explains how the SLC 500 processor reads thermocouple or millivolt
analog input data from the module.
Read this chapter to familiarize yourself further with your
thermocouple/mV analog input module. This chapter covers:
• general description and hardware features
• an overview of system and module operation
• block diagram of channel input circuits
General Description This module is designed exclusively to mount into 1746 I/O racks for
use with SLC 500 fixed and modular systems. The module stores
digitally converted thermocouple/mV analog data in its image table
for retrieval by all fixed and modular SLC 500 processors. The
module supports connections from any combination of up to eight
thermocouple/mV analog sensors.
Input Ranges
The following tables define thermocouple types and associated
temperature ranges and the millivolt analog input signal ranges that
each of the module’s input channels support. To determine the
practical temperature range of your thermocouple, refer to the
specifications in appendix A.
Thermocouple Temperature Ranges
Millivolt Input Ranges
Type °C Temperature Range °F Temperature Range
J-210°C to +760°C -346°F to +1400°F
K -270°C to +1370°C -454°F to +2498°F
T -270°C to +400°C -454°F to +752°F
B +300°C to +1820°C +572°C to +3308°F
E -270°C to +1000°C -454°F to +1832°F
R 0°C to +1768°C +32 F to +3214°F
S 0°C to +1768°C +32°F to +3214°F
N 0°C to +1300°C +32°F to +2372°F
CJC Sensor -25°C to +105°C -13°F to +221 °F
-50 to +50 mV
-100 to +100 mV

1-2 Module Overview
Publication 1746-6.22
Each input channel is individually configured for a specific input
device, and provides open-circuit, over-range, and under-range
detection and indication.
Hardware Features
The module fits into any single slot for I/O modules in either an SLC
500 modular system or an SLC 500 fixed system expansion chassis
(1746-A2), except the zero slot which is reserved for the processor. It
is a Class 1 module using 8 input words and 8 output words.1
The module contains a removable terminal block providing
connections for eight thermocouple and/or analog input devices. On
the terminal block are two cold-junction compensation (CJC) sensors
that compensate for the cold junction at ambient temperature. It
should also be noted there are no output channels on the module.
Configure the module with software rather than with jumpers or
switches.
1. Requires use of a Block Transfer when used in a remote rack with a 1747-ASB.
Important: There is a jumper (JP1) on the circuit board. The module
is shipped with the jumper in the up position as
illustrated below. Do not change the position of JP1. The
jumper is used for test purposes only.
SLC 500
CAT SERIALNO.
THERMOCOUPLE/mV INPUT MODULE
MADE IN USAFAC 1M
INPUT SIGNAL RANGES
THERMOCOUPLE TYPES: VOLTAGE:
±100mVDC to +100mVDC
±50mVDC to +50mVDC
SER FRN)ULLISTED IND. CONT. EQ.
FOR HAZ. LOC. A196
CLASS I, GROUPS A, B, CAND D, DIV.2
OPERATING
)
SA J, K, T, E, R, S, B, N
TEMPERATURE CODE T3C
1746NT4 NT4±xxx x
MODULE
0
14 5
2
12 3
CHANNEL
STATUS
THERMOCOUPLE/mV
INPUT
CJC A+
CJC A-
CHL 0+
CHL 0-
SHIELD
CHL 1+
CHL 1-
CHL 2+
CHL 2-
SHIELD
CHL 3+
CHL 3-
CHL 4+
CHL 4-
SHIELD
CHL 5+
CHL 5-
CHL 6+
CHL 6-
SHIELD
CHL 7+
CHL 7-
CJC B+
CJC B-
1746-NT8
JP1
Side Label
Self-Locking Tabs
Door Label
Channel Status
LEDs (Green)
Module Status
LED (Green)
Removable
Terminal Block
CJC Sensors
Cable Tie Slots
Jumper - Do Not Move.

Module Overview 1-3
Publication 1746-6.22
Hardware Features
Diagnostic LEDs
The module contains diagnostic LEDs that help you identify the
source of problems that may occur during power-up or during normal
operation. Power-up and channel diagnostics are explained in Chapter
6, Testing Your Module.
System Overview The module communicates with the SLC 500 processor and receives
+5V dc and +24V dc power from the system power supply through
the parallel backplane interface. No external power supply is
required. You may install as many thermocouple modules in the
system as the power supply can support.
Each module channel can receive input signals from a thermocouple
or a mV analog input device. You configure each channel to accept
either one. When configured for thermocouple input types, the
module converts analog input voltages into cold-junction
compensated and linearized, digital temperature readings. The
module uses National Institute of Standards and Technology (NIST)
ITS-90 for thermocouple linearization.
When configured for millivolt analog inputs, the module converts
analog values directly into digital counts. The module assumes that
the mV input signal is linear.
System Operation
At power-up, the module checks its internal circuits, memory, and
basic functions. During this time the module status LED remains off.
If the module finds no faults, it turns on its module status LED.
Hardware Function
Channel Status LED Indicators Display operating and fault status of channels 0-7
Module Status LED Displays operating and fault status of the module
Side Label (Nameplate) Provides module information
Removable Terminal Block Provides electrical connection to input devices
Door Label Permits easy terminal identification
Cable Tie Slots Secure and route wiring from module
Self Locking Tabs Secure module in chassis slot
SLC 500
Processor
Thermocouple
Input
Module
Thermocouple or mV
Analog Signals
Channel Data Word
Channel Status Word
Channel Configuration Word

1-4 Module Overview
Publication 1746-6.22
After completing power-up checks, the module waits for valid
channel configuration data from your SLC ladder logic program
(channel status LEDs are off). After channel configuration data is
transferred and channel enable bits are set, the enabled channel status
LEDs turn on. Then the channel continuously converts the
thermocouple or millivolt input to a value within the range you
selected for the channel.
Each time the module reads an input channel, the module tests that
data for a fault, i.e. over-range or under-range condition. If open-
circuit detection is enabled, the module tests for an open-circuit
condition. If it detects an open-circuit, over-range, or under-range
condition, the module sets a unique bit in the channel status word and
causes the channel status LED to flash.
The SLC processor reads the converted thermocouple or millivolt
data from the module at the end of the program scan, or when
commanded by the ladder program. After the processor and module
determine that the data transfer was made without error, the data can
be used in your ladder program.
Module Operation
The module’s input circuitry consists of eight differential analog
inputs, multiplexed into an A/D convertor. The A/D convertor reads
the analog input signals and converts them to a digital value. The
input circuitry also continuously samples the CJC sensors and
compensates for temperature changes at the cold junction (terminal
block).
Module Addressing
The module requires eight words each in the SLC processor’s input
and output image tables. Addresses for the module in slot e are as
follows:
I:e.0-7 thermocouple/mV or status data for channels 0-7,
respectively (dependent on bit in configuration word).
O:e.0-7 configuration data for channels 0-7, respectively.
See “Module Addressing” on page 3-1 to see the module’s image
table.

Module Overview 1-5
Publication 1746-6.22
Block Diagram
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
Terminal Block Module Circuitry
CJCA Sensor
Shield
Shield
Shield
Shield
CJCB Sensor
User Selected
Filter Frequency
Digital
Value
Analog to
Digital
Converter Digital
Filter
multiplexer
Analog
Ground
Within
12.5V
ungrounded
thermocouple
grounded
thermocouple
Important: When using multiple thermocouples, the potential
between any two channels cannot exceed the channel-to-
channel differential voltage (12.5 volts). For more
information, see Appendix B.

1-6 Module Overview
Publication 1746-6.22
Linear Millivolt Device Compatibility
A large number of millivolt devices may be used with the 1746-NT8
module. For this reason we do not specify compatibility with any
particular device.
However, millivolt applications often use strain gage bridges. A
resistive voltage divider using fixed resistors is recommended for this
application. The circuit diagram below shows how this connection is
made.
+
-
+
Strain
Gage
Bridge
1746-NT8
fixed
fixed
variable
fixed
Voc
Channel
Input
Note: The resistors should be selected to ensure that the
differential input voltage is less than or equal to ±100
mV.

Publication 1746-6.22
Chapter 2
Installing And Wiring Your Module
Read this chapter to install and wire your module. This chapter
covers:
• avoiding electrostatic damage
• determining power requirements
• installing the module
• wiring signal cables to the module’s terminal block
Electrostatic Damage Electrostatic discharge can damage semiconductor devices inside this
module if you touch backplane connector pins. Guard against
electrostatic damage by observing the following precautions:
!
ATTENTION: Electrostatically Sensitive
Components
• Before handling the module, touch a grounded
object to rid yourself of electrostatic charge.
• Handle the module from the front, away from the
backplane connector. Do not touch backplane
connector pins.
• Keep the module in its static-shield container
when not in use or during shipment.
Failure to observe these precautions can degrade
the module’s performance or cause permanent
damage.

2-2 Installing And Wiring Your Module
Publication 1746-6.22
Power Requirements The module receives its power through the SLC 500 chassis
backplane from the fixed or modular +5 VDC/+24 VDC chassis
power supply. The maximum current drawn by the module is shown
in the table below.
Maximum Current Drawn by the Module
Considerations for a Modular System
Place your module in any slot of an SLC 500 modular, or modular
expansion chassis, except for the left-most slot (slot 0) reserved for
the SLC processor or adapter modules.
When using the module with a modular system, add the values shown
above to the requirements of all other modules in the SLC to prevent
overloading the chassis power supply. Refer to the SLC 500 Modular
Hardware Style Instruction and Operating Manual, publication 1747-
6.2.
5VDC Amps 24VDC Amps
0.120 0.070

Installing And Wiring Your Module 2-3
Publication 1746-6.22
Fixed I/O Chassis - I/O Module Compatibility
The following chart depicts the range of current combinations
supported by the fixed I/O expansion chassis. To use it, find the
backplane current draw and operating voltage for both modules being
used in the chassis. These specifications are found in the table
alongside the chart.
Next, plot each of the currents on the chart below. If the point of
intersection falls within the operating region, the combination is
valid. If not, the combination cannot be used in a 2-slot, fixed I/O
chassis.
Module Current Draw - Power Supply Loading
I/O Module 5V 24V I/O Module 5V 24V
BAS .150 .040 KE .150 .040
BASn .150 .125 KEn .150 .125
DCM .360 .000 NI4 .025 .085
FIO4I .055 .150 NI8 .200 .100
FIO4V .055 .120 NIO4I .055 .145
HS .300 .000 NIO4V .055 .115
HSTP1 .200 .000 NO4I .055 .195
IA4 .035 .000 NO4V .055 .145
IA8 .050 .000 NR4 .050 .050
IA16 .085 .000 NT4 .060 .040
IB8 .050 .000 OA16 .370 .000
IB16 .085 .000 OA8 .185 .000
IB32 .106 .000 OAP12 .370 .000
IC16 .085 .000 OB8 .135 .000
IG16 .140 .000 OB16 .280 .000
IH16 .085 .000 OB16E .135 .000
IM4 .035 .000 OB32 .452 .000
IM8 .050 .000 OBP8 .135 .000
IM16 .085 .000 OBP16 .250 .000
IN16 .085 .000 OG16 .180 .000
IO4 .030 .025 OV8 .135 .000
IO8 .060 .045 OV16 .270 .000
IO12 .090 .070 OV32 .452 .000
ITB16 .085 .000 OVP16 .250 .000
ITV16 .085 .000 OW16 .170 .180
IV8 .050 .000 OW4 .045 .045
IV16 .085 .000 OW8 .085 .090
IV32 .106 .000 OX8 .085 .090
Example: Plot IN16 and NIO4V
IN16 = 0.085 at 5V dc and 0A at 24V dc
NIO4V = 0.055A at 5V dc and 0.115A at 24V dc
1. Addcurrent drawsofboth modulesat5V dc toget0.14
(140mA)
2. Plot this point on the chart above (140mA at 5V dc).
3. Add current draws of both modules at 24V dc to get
0.115A (115mA)
4. Plot current draw at 24V dc (115mA at 24V dc)
5. Note the point of intersection on the chart above
(marked x). This combination falls within the valid
operating region for the fixed I/O chassis.
Important: The1746-NO4I and 1746-NO4V analog output
modules may require an external power supply.
50
100
150
200
250
300
350
400
450
50
100
150
200
at 5V dc
Current
(mA)
OA16 and
(0, 455)
OW16 and IA16
(180, 255)
Current (mA) at 24V
x
Plotted from
Example
Shown Below
Valid Operating
Region
l
l

2-4 Installing And Wiring Your Module
Publication 1746-6.22
When using the BAS or KE module to supply power to a 1747-AIC
Link Coupler, the link coupler draws its power through the module.
The higher current drawn by the AIC at 24V dc is shown in the table
as BASn (BAS networked) and KEn (KE networked). Be sure to use
these current draw values if the application uses the BAS or KE
module in this way.
General
Considerations Most applications require installation in an industrial enclosure to
reduce the effects of electrical interference. Thermocouple inputs are
highly susceptible to electrical noises due to the small amplitudes of
their signal (microvolt/°C).
Group your modules to minimize adverse effects from radiated
electrical noise and heat. Consider the following conditions when
selecting a slot for the thermocouple module. Position the module:
• in a slot away from sources of electrical noise such as hard-
contact switches, relays, and AC motor drives
• away from modules which generate significant radiated heat,
such as the 32-point I/O modules
In addition, route shielded twisted pair thermocouple or millivolt
input wiring away from any high voltage I/O wiring.
Remember that in a modular system, the processor or
communications adapter always occupies the first slot of the rack.