Rockwell Automation Allen-Bradley 1794-IRT8 User manual

User Manual Original Instructions
FLEX I/O Thermocouple/RTD/
Millivolt Input Module
Catalog Numbers 1794-IRT8,1794-IRT8XT

2Rockwell Automation Publication 1794-UM012D-EN-P - March 2023
FLEX I/O Thermocouple/RTD/Millivolt Input Module User Manual
Important User Information
Read this document and the documents listed in the additional resources section about installation, configuration, and operation of this equipment before you
install, configure, operate, or maintain this product. Users are required to familiarize themselves with installation and wiring instructions in addition to
requirements of all applicable codes, laws, and standards.
Activities including installation, adjustments, putting into service, use, assembly, disassembly, and maintenance are required to be carried out by suitably trained
personnel in accordance with applicable code of practice.
If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.
In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and requirements associated with any
particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for actual use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software described in this manual.
Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell Automation, Inc., is prohibited.
Throughout this manual, when necessary, we use notes to make you aware of safety considerations.
These labels may also be on or inside the equipment to provide specific precautions.
The following icon may appear in the text of this document.
Rockwell Automation recognizes that some of the terms that are currently used in our industry and in this publication are not in alignment with the
movement toward inclusive language in technology. We are proactively collaborating with industry peers to find alternatives to such terms and
making changes to our products and content. Please excuse the use of such terms in our content while we implement these changes.
WARNING: Identifies information about practices or circumstances that can cause an explosion in a hazardous environment, which
may lead to personal injury or death, property damage, or economic loss.
ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property
damage, or economic loss. Attentions help you identify a hazard, avoid a hazard, and recognize the consequence.
IMPORTANT Identifies information that is critical for successful application and understanding of the product.
SHOCK HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that dangerous
voltage may be present.
BURN HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that surfaces may
reach dangerous temperatures.
ARC FLASH HAZARD: Labels may be on or inside the equipment, for example, a motor control center, to alert people to potential
Arc Flash. Arc Flash will cause severe injury or death. Wear proper Personal Protective Equipment (PPE). Follow ALL Regulatory
requirements for safe work practices and for Personal Protective Equipment (PPE).
Identifies information that is useful and can help to make a process easier to do or easier to understand.

Rockwell Automation Publication 1794-UM012D-EN-P - March 2023 3
Table of Contents
Preface
About This Publication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Download Firmware, AOP, EDS, and Other Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Summary of Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 1
Overview of FLEX I/O and Your
Thermocouple, RTD, and Millivolt
Input Module
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
The FLEX System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Types of Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
What the FLEX I/O Input Module Does . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
The FLEX I/O Module in a Logix Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Physical Features of Your Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 2
Install Your FLEX I/O Input
Module
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Before You Install Your Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Series A and Series B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Install the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Mount on a DIN Rail. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Mount on a Panel or Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Mount the FLEX I/O Module on the Terminal Base Unit . . . . . . . . . . . . . . . . . . . . . . . . . 16
Wiring Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Connect Wiring to the FLEX I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Identify RTD Wire Pairs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Chapter 3
Configure Your FLEX I/O Module
with RSLogix 5000 Software
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Add and Configure the FLEX I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Chapter 4
Read and Write Configuration
Maps for the FLEX I/O Module
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Configure Your Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Configurable Options and Their Effect on the Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Options that Affect All Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Options that Affect Each Group of Four Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Sensor Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Read Data From the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Map Data for the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Block-transfer Read and Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Series A Functionality in a Series B Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4Rockwell Automation Publication 1794-UM012D-EN-P - March 2023
Table of Contents
Chapter 5
Calibrate Your Module Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
When and How to Calibrate Your FLEX I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Tools and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Calibrate Your Input Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Calibration Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Read and Write Words for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Gain Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Current Source Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Cold Junction Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Channel Loop Compensation Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Appendix A
Troubleshoot the Module Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Module Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Appendix B
Electronic Data Sheet (EDS) Files Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Updating EDS File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
EDS Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Appendix C
Program Your Module with PLC
Family Processors
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Enter Block Transfer Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
PLC-2 Family Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
PLC-3 Family Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
PLC-5 Family Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
PLC-5/250 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Appendix D
Resolution Curves for
Thermocouples
Type B Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Type E Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Type C Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Type J Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Type K Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Type R Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Type S Thermocouple. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Type T Thermocouple. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Type N Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Type TXK/XK(L) Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Rockwell Automation Publication 1794-UM012D-EN-P - March 2023 5
Preface
About This Publication This manual is a reference guide for the FLEX™ I/O Thermocouple, RTD, Millivolt Input Modules. It
describes the procedures for installing, configuring, and troubleshooting your module.
Download Firmware, AOP,
EDS, and Other Files
Download firmware, associated files (such as AOP, EDS, and DTM), and access product release
notes from the Product Compatibility and Download Center at rok.auto/pcdc.
Summary of Changes This publication contains the following new or updated information. This list includes substantive
updates only and is not intended to reflect all changes.
Additional Resources These documents contain additional information concerning related products from Rockwell
Automation. You can view or download publications at rok.auto/literature.
Topic Page
Updated template throughout
Added inclusive terminology statement 2
Corrected wording in an Important table 18
Resource Description
FLEX I/O Thermocouple/RTD Input Analog Module Installation Instructions,
publication 1794-IN050 Information on how to install the Thermocouple/Millivolt Input Modules (1794-IRT8, 1794-IRT8XT).
EtherNet/IP Network Devices User Manual, publication ENET-UM006 Describes how to configure and use EtherNet/IP™ devices to communicate on the EtherNet/IP
network.
ControlNet Network Configuration User Manual, publication CNET-UM001 Describes how to use ControlNet® communication modules with Logix 5000® controllers.
Ethernet Reference Manual, publication ENET-RM002 Describes basic Ethernet concepts, infrastructure components, and infrastructure features.
Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1 Provides general guidelines for installing a Rockwell Automation industrial system.
Product Certifications website, rok.auto/certifications Provides declarations of conformity, certificates, and other certification details.

6Rockwell Automation Publication 1794-UM012D-EN-P - March 2023
Preface
Notes:

Rockwell Automation Publication 1794-UM012D-EN-P - March 2023 7
Chapter 1
Overview of FLEX I/O and Your Thermocouple,
RTD, and Millivolt Input Module
Overview This chapter provides a description of the FLEX I/O Thermocouple, RTD, and Millivolt Input module
and an overview of how it communicates with programmable controllers.
The FLEX System FLEX I/O is a small, modular I/O system for distributed applications that performs all functions of
rack-based I/O. The FLEX system contains the following components shown:
• Adapter – Transfers read and write configuration data to and from the I/O module.
• Terminal base – Contains a terminal strip to terminate wiring for two- or three-wire devices.
• I/O module – Contains the bus interface and circuitry that is needed to perform specific
functions that are related to your application.
The FLEX system consists of an adapter, terminal base unit, DIN rail, power supply, and adapter
cabling components. You can use up to eight terminal bases per adapter.
For detailed instructions on how to set up and install your module, see Install Your FLEX I/O Input
Module on page 11.
Types of Modules The module refers to the following catalogs:
The module accepts up to eight thermocouple or RTD inputs. The inputs are nonisolated and are
selected with analog multiplexers. The inputs accept millivolt or resistive inputs. Default input
spans are -40.00 mV… +100.00 mV or 0.0…500.0 Ω. Fault indicators are located field side.
No switches or jumpers are used on the TC and RTD Input module. The inputs have both fixed
hardware filters and selectable firmware digital filters.
I/O moduleTerminal baseAdapter
1794-IRT8
2
+
2
+
Catalog Number Voltage Inputs Description
1794-IRT8 24V DC 8 Analog – 8 pt, 16 bit non-isolated RTD, thermocouple, and mV
Input module
1794-IRT8XT 24V DC 8 Analog – 8 pt, 16 bit non-isolated RTD, thermocouple, and mV
Input module designed for extended temperature.

8Rockwell Automation Publication 1794-UM012D-EN-P - March 2023
Chapter 1 Overview of FLEX I/O and Your Thermocouple, RTD, and Millivolt Input Module
What the FLEX I/O Input
Module Does
The module is a high-speed, high-accuracy temperature and millivolt measuring module that
accepts thermocouple inputs, 2-, 3-, and 4-wire RTD inputs, and mV source inputs.
It offers the following:
• Wire-off, overrange, and underrange detection
• Good common mode rejection
• Usage with long thermocouple wiring
• Usage with grounded or ungrounded thermocouples
The Series B version of 1794-IRT8 provides capability to work with grounded thermocouples.
Use cold junction compensators (catalog number 1794-CJC2) in thermocouple mode. Two cold
junction compensators are shipped with the 1794-IRT8.
The FLEX I/O Module in a
Logix Control System
The FLEX I/O Thermocouple, RTD, and Millivolt modules are intelligent modules that interface analog
signals with Allen-Bradley® programmable controllers through a FLEX I/O adapter.
The adapter transfers data to and from the module. These transfers allow:
• The adapter to obtain input or output values and status from the module.
• Establishing the mode of operation through a process called configuration.
Figure 1 shows the flow of communication between the adapter and the I/O module.
Figure 1 - Typical Communication Between the Adapter and a Module
IN 0 IN 2 IN 4 IN 6IN 1 IN 3 IN 5 IN 7
TC RTD INPUT 8 CHANNEL
3
1794-IRT8
PWR
FF F F F F F F
The adapter transfers your configuration data.
Flexbus
External devices transmit
analog signals to the module.
The module converts analog
signals into binary format and
stores these values until the
adapter requests their transfer.
The adapter receives data from the
modules and stores it in the data table.
The adapter determines that the transfer was made
without error and input values are within specified
range.
Your ladder program can use “and/or” to move the
data (if valid) before it is overwritten by the transfer
of new data in a subsequent transfer.
1
4
5
6
2
3
New configuration data can be sent to the module
anytime during operation.
7
FLEX Adapters:
1794-ACN15
1794-ACNR15
1794-ACNR15K
1794-ADN
1794-AENT
1794-APBDPV1
1794-ASB
Adapter
1794-AENT
shown

Rockwell Automation Publication 1794-UM012D-EN-P - March 2023 9
Chapter 1 Overview of FLEX I/O and Your Thermocouple, RTD, and Millivolt Input Module
Figure 2 shows a broader view of how the FLEX I/O module interfaces with the different elements in
a Logix system.
Figure 2 - FLEX I/O Modules in a Logix System
In this example, the FLEX I/O module communicates with the controller through the adapter. The
controller can produce and consume tags. It can initiate MSG instructions that send and receive
data or configure devices. Configuration of devices and the network is done through the personal
computer running the controller and configuration software.
To learn about the prerequisites and steps to configure your FLEX I/O module using Studio 5000
Logix Designer® application(1), see Configure Your FLEX I/O Module with RSLogix 5000 Software on
page 21.
Physical Features of Your
Module
The module label identifies the keyswitch position, wiring, and module type. A removable label
provides space for writing individual designations per your application. Indicators are provided to
identify input fault conditions, and to show when power is applied to the module.
Figure 3 - Module Label and Indicators
Bridge
PanelView
TM
terminal
Ethernet
PC running
controller and
Rockwell Automation
configuration software
1794 adapter
1794 FLEX I/O module
FLEX system
Logix 5000 controller
(1) Studio 5000 Logix Designer is the replacement for RSLogix 5000® (version 20 or later). It provides one software package for
discrete, process, batch, motion, safety, and drive-based applications.
ATTENTION: The following publications provide more information about
EtherNet/IP, and ControlNet modules in a Logix 5000 system:
• EtherNet/IP Network Devices User Manual, publication ENET-UM006.
• ControlNet Network Configuration User Manual, publication CNET-UM001.
IN 0 IN 2 IN 4 IN 6IN 1 IN 3 IN 5 IN 7
TC RTD INPUT 8 CHANNEL
3
1794-IRT8
PWR
FF F FF F F F
1794-IRT8
Input designators
Module type
Removable label
Keyswitch
position indicator (#3)
Power on indicator

10 Rockwell Automation Publication 1794-UM012D-EN-P - March 2023
Chapter 1 Overview of FLEX I/O and Your Thermocouple, RTD, and Millivolt Input Module
Notes: