TECH LIBRARY 1 SVPP Supplier Manuals Rockwell 1756-um540_-en-p 1756-IRT8I.pdf

High Resolution Analog I/O Modules Catalog Numbers 1756-IF8I, 1756-IRT8I, 1756-OF8I, 1756-IR12, 1756-IT16

User Manual Original Instructions

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.

Labels may also be on or inside the equipment to provide specific precautions.

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).

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Table of Contents

Summary of Changes New and Updated Information Preface Additional Resources

Chapter 1 Analog I/O Module Operation in the ControlLogix System

Before You Begin Ownership Configure a Module Direct Connections Input Module Operation

Requested Packet Interval (RPI) Input Modules in a Local Chassis Input Modules in a Remote Chassis Trigger Event Tasks

Output Module Operation Output Modules in a Local Chassis Output Modules in a Remote Chassis

Listen-only Mode

Chapter 2 Analog I/O Module Features Common Analog I/O Features

CIP Sync Timestamp of Data Rolling Timestamp of Data Floating Point Data Format Module Quality Reporting Calibration Fault and Status Reporting Configurable Software Latching of Alarms Module Inhibiting Electronic Keying Elegant Migration Emulation Mode

Relationship between Module Resolution and Scaling Module Resolution Scaling

Calibration Calibrated Accuracy Error Calculated over Hardware Range RTD and Thermocouple Error Calculations

RTD Error Thermocouple Error Module Error at 25 °C (77 °F)

Thermocouple Resolution Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 7

Chapter 3 1756-IF8I Isolated Analog Input Module

1756-IF8I Module Features Internal Loop Power Source Multiple Input Ranges Notch Filter Underrange/Overrange Detection Digital Filter Process Alarms Rate Alarm Sensor Offset Wire Off Detection Synchronized Sampling

1756-IF8I Diagrams Fault and Status Reporting

Chapter 4 Temperature-sensing Analog Modules

Common Module Features Module Input Ranges Notch Filter Underrange/Overrange Detection Digital Filter Process Alarms Rate Alarm Sensor Offset 10 Ohm Copper Offset Wire Off Detection Temperature Units Sensor Types 1756-IRT8I Thermocouple Wire Length Compensation Synchronized Sampling Cold Junction Compensation

1756-IRT8I Diagrams 1756-IR12 Diagrams 1756-IT16 Diagrams Fault and Status Reporting

Chapter 5 1756-OF8I Isolated Analog Output Module

1756-OF8I Module Features Multiple Output Ranges Channel Offset Ramping/Rate Limiting Hold for Initialization Clamping/Limiting Clamp/Limit Alarms Data Echo

1756-OF8I Diagrams 8 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016

Drive Different Loads with the 1756-OF8I Module Fault and Status Reporting

Chapter 6 Install ControlLogix Analog I/ O Modules

Install the I/O Module Key the Removable Terminal Block Connect Wiring

Connect the Grounded End of the Cable Connect the Ungrounded End of the Cable RTB Types RTB Wiring Recommendations

Assemble the RTB and the Housing Choose Extended-depth Housing

Cabinet Size Considerations with Extended-depth Housing . 115 Install the Removable Terminal Block Remove the Removable Terminal Block Remove the Module from the Chassis

Chapter 7 Configure ControlLogix Analog I/ O Modules

Create a New Module Module Definition

Edit the Configuration Connection Tab Configuration Tab Calibration Tab Alarm Configuration Tab Limit Configuration Tab

Copy Channel Configuration View the Module Tags

Chapter 8 Calibrate the ControlLogix Analog I/O Modules

Difference between Calibrating an Input Module and an Output Module

Calibrate Via Profile or Ladder Calibrate the Input Modules

Calibrate the 1756-IF8I Module Via the Profiles Calibrate the Temperature-sensing Modules

Calibrate the Output Module Calibrate the 1756-OF8I Module for a Current Output Type 153

Chapter 9 Troubleshoot Your Module Status Indicators for the 1756-IF8I Module

Status Indicators for the 1756-IRT8I Module Status Indicators for the 1756-IR12 Module Status Indicators for the 1756-IT16 Module Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 9

Status Indicators for the 1756-OF8I Module Use Logix Designer Application for Troubleshooting

Fault Type Determination Troubleshoot Incorrect Readings on the Module

1756-IRT8I and 1756-IT16 Modules - Incorrect Temperature Readings 1756-IRT8I and 1756-IR12 Modules - Incorrect RTD Readings 1756-IF8I Module - Incorrect Input Voltage/Current Readings 1756-OF8I Module - Incorrect Output Voltage/Current Readings

Appendix A Analog I/O Module Tag Definitions

Access the Tags 1756-IF8I Module Tags

Configuration Tags Input Tags Output Tags

1756-IRT8I Module Tags Configuration Tags Input Tags Output Tags

1756-IR12 Module Tags Configuration Tags Input Tags Output Tags

1756-IT16 Module Tags Configuration Tags Input Tags Output Tags

1756-OF8I Module Tags Configuration Tags Input Tags Output Tags

Appendix B Choose the Correct Power Supply Power-sizing Chart

Appendix C 1492 Analog Interface Modules 10 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016

Summary of Changes

This manual contains new and updated information.

New and Updated Information

This table contains the changes made in this revision.

Topic Page

Added references to Migrating from 6 Channel 1756 Analog Modules to 8 Channel 1756 Analog Modules, publication 1756-RM011

Additional Resources

Updated Broadcast Method text 23

Updated Listen-Only important 24

Updated text common causes of uncertain data in Module Quality Reporting 28

Added section Elegant Migration Emulation Mode 33

Updated text in Relationship between Noise Rejection Level and RPI Setting 48

Updated 1756-IF8I Notch Filter Settings 49

Added text to Alarm Deadband 53

Updated 1756-IF8I Module Fault and Status Reporting 62

Update Module Input Ranges 64

Updated 1756-IRT8I Notch Filter Settings 67

Added text to Alarm Deadband 71

Updated text in Module Wire Off Conditions 74

Updated 1756-OF8I Module Fault and Status Reporting 101

Updated text in Calibrate Via Profile or Ladder 139

Updated descriptions in Status Indicators for the 1756-IF8I Module 159

Updated descriptions in Status Indicators for the 1756-IRT8I Module 160

Updated descriptions in Status Indicators for the 1756-IR12 Module 160

Updated descriptions in Status Indicators for the 1756-IT16 Module 161

Updated descriptions in Status Indicators for the 1756-OF8I Module 161

Updated text in Troubleshoot Incorrect Readings on the Module 164

Updated 1756-IF8I Module - Configuration Tags Ch[x].ProcessAlarmLatch and Ch[x].RateAlarmLatch

Updated 1756-IF8I Module - Input Tags CIPSyncValid 179

Updated 1756-IRT8I Module - Configuration Tags Ch[x].ProcessAlarmLatch and Ch[x].RateAlarmLatch

Updated Tags in Analog I/O Module Tag Definitions Throughout Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 11

Summary of Changes Notes:

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Preface

This manual describes how to install, configure, and troubleshoot ControlLogix® analog I/O modules.

You must be able to program and operate a ControlLogix® controller to use your analog I/O modules. If you need additional information, see Additional Resources on page 13.

ControlLogix analog I/O modules convert analog signals to digital values for inputs and convert digital values to analog signals for outputs. Controllers use these signals for control purposes.

By using the Producer/Consumer network model, ControlLogix analog I/O modules produce information when needed while providing additional system functions.

Additional Resources These documents contain additional information concerning related products from Rockwell Automation.

You can view or download Rockwell Automation publications at http:/ www.rockwellautomation.com/literature/.

To order paper copies of technical documentation, contact your local Allen-Bradley distributor or Rockwell Automation sales representative.

Resource Documentation

1756 ControlLogix I/O Specifications, publication 1756-TD002

Provides specifications for ControlLogix analog and digital I/O modules as well as the accessories that can be used with each.

Migrating 6-Channel 1756 Analog Modules to 8- Channel 1756 Analog Modules 1756-RM011

Provides information on how to migrate the 1756 Isolated Analog I/O 6-channel modules to the 8-channel modules.

ControlLogix Digital I/O Modules User Manual, publication 1756-UM058

Provides information on how to install, configure, and troubleshoot ControlLogix digital I/O modules.

1756 ControlLogix Chassis and Power Supplies Installation Instructions, publication 1756-IN005

Provides information on how to install a wide range of ControlLogix chassis, power supplies, and chassis adapter modules.

Integrated Architecture and CIP Sync Configuration Application Technique, publication IA-AT003

Describes how to configure CIP Sync with Integrated Architecture® products and applications.

ControlLogix System User Manual, publication 1756 UM001

Describes how to install, configure, program, and operate a ControlLogix system.

Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1

Provides general guidelines for installing a Rockwell Automation industrial system.

Rockwell Automation Product Certifications website

Provides declarations of conformity, certificates, and other certification details.

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Preface

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Chapter 1

Analog I/O Module Operation in the ControlLogix System

ControlLogix® controllers use analog I/O modules to control devices in a ControlLogix control system. The modules are installed in a ControlLogix chassis and use a removable terminal block (RTB) or a Bulletin 1492 interface module(1) cable to connect to field-side wiring.

The modules use the Producer/Consumer network communication model. This communication is an intelligent data exchange between modules and other system devices in which each module produces data without first being polled.

Before You Begin Before you install and use your module, complete the following tasks:

• Install and ground a 1756 ControlLogix chassis and power supply(2). You can use a standard power supply or a redundant power supply.

For more information on how to install the 1756 ControlLogix chassis and power supplies, see Additional Resources on page 13.

• Verify that you have an RTB or IFM and its components.

Topic Page

Before You Begin 15

Ownership 17

Configure a Module 17

Direct Connections 18

Input Module Operation 19

Output Module Operation 22

Listen-only Mode 24

(1) The ControlLogix system has been agency certified using only the ControlLogix RTBs (catalog numbers 1756-TBCH, 1756-TBNH, 1756-TBSH and 1756-TBS6H). Any application that requires agency certification of the ControlLogix system using other wiring termination methods can require application specific approval by the certifying agency.

(2) In addition to standard ControlLogix power supplies, ControlLogix Redundant Power Supplies are also available for your application.

For more information on these supplies, see the ControlLogix Selection Guide, publication 1756-SG001, or contact your local distributor or Rockwell Automation representative.

IMPORTANT RTBs and IFMs are not included with your module purchase.

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Chapter 1 Analog I/O Module Operation in the ControlLogix System Figure 1 - Parts Illustration of the ControlLogix Isolated Analog I/O Module

Table 1 - Types of ControlLogix Isolated Analog I/O Modules

Cat. No. Description RTB Used Page

1756-IF8I 8-point general-purpose isolated analog current/voltage input module

36-pin (1756-TBCH or

1756-TBS6H)

1756-IRT8I 8-point isolated combined temperature and mV sensing input module

1756-OF8I 8-point general-purpose isolated analog current/voltage output module

Removable Terminal Block

Item Description

1 Backplane connector - Interface for the ControlLogix system that connects the module to the backplane.

2 Top and bottom guides - Guides provide assistance in seating the RTB or IFM cable onto the module.

3 Status indicators - Indicators display the status of communication, module health, and input/output (I/O) devices. Indicators help in troubleshooting anomalies.

4 Connector pins - Input/output, power, and grounding connections are made to the module through these pins with the use of an RTB or IFM.

5 Locking tab - The locking tab anchors the RTB or IFM cable on the module, maintaining wiring connections.

6 Slots for keying - Mechanically keys the RTB to prevent inadvertently making the wrong wire connections to your module.

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Analog I/O Module Operation in the ControlLogix System Chapter 1 Ownership Every I/O module in the ControlLogix system must be owned by a ControlLogix controller. This controller performs the following:

• Stores configuration data for every module that it owns.

• Resides in the local or remote chassis in regard to the position of the I/O module.

• Sends the I/O module configuration data to define the behavior of the module and begin operation in the control system.

Each ControlLogix I/O module must continuously maintain communication with its owner to operate normally. Typically, each module in the system has only one owner. Some Input modules can have multiple owners. Output modules, and Input modules which have an Output image like the 1756-IF8I and IRT8I however, are limited to one owner.

Configure a Module You use the I/O configuration portion of the Studio 5000 Logix Designer® application to configure each I/O module. An I/O module can reside in either of the following:

• Local chassis - The chassis in which the owner-controller resides.

Controller I/O Modules Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 17

• Remote chassis - A chassis that does not contain the module’s owner-controller but is connected to the local chassis over the EtherNet/IP network or ControlNet network.

The Logix Designer application transfers configuration data to the controller during the program download. Then, data is transferred to the I/O modules in the local and remote chassis.

The I/O module can operate immediately after the project download from the owner-controller is complete.

Direct Connections A direct connection is a real-time data transfer link between the controller and the device that occupies the slot that the configuration references.

When you download module configuration to a controller, the controller attempts to establish a direct connection to each module referenced by the configuration.

Controller I/O Modules

Local Chassis Remote Chassis

EtherNet/IP Network

IMPORTANT ControlLogix analog I/O modules support only direct connections.

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If controller configuration refers to a chassis slot in the system, the controller periodically checks for the presence of a device there. If a device is detected, the controller sends the configuration, and one of the following occurs:

• If the configuration is appropriate to the module detected, a connection is made and operation begins.

• If the configuration is not appropriate to the module detected, the data is rejected and the Logix Designer application indicates that an error occurred.

The configuration can be inappropriate for any of a number of reasons. For example, the configuration or a module can include a mismatch in electronic keying that prevents normal operation.

The controller maintains and monitors its connection with a module. Any break in the connection, for example, the removal of the module from the chassis while under power, causes a fault.

The Logix Designer application indicates that the fault occurred in the fault status bits associated with the module. The Logix Designer application monitors the fault status bits to annunciate the failures of a module.

Input Module Operation In traditional I/O systems, controllers periodically poll input modules to obtain their input status.

In the ControlLogix system, the controller does not poll the analog input modules. Instead, the modules broadcast their input data, that is, channel and status data, to their backplane periodically.

Requested Packet Interval (RPI)

The RPI is a configurable parameter that defines a specific period when the module broadcasts input data to the backplane. Valid RPI values are 1…750 ms.

The default value is 100 ms for inputs and 10 ms for outputs.

Set the RPI value at initial module configuration and adjust it as necessary only when the controller is in Program mode.

IMPORTANT Other ControlLogix analog input modules offer the Real Time Sample (RTS) parameter that determines when channel data is scanned and stored on the module’s on-board memory until broadcast to the chassis backplane.

The 1756-IF8I, 1756-IRT8I, 1756-IR12, and 1756-IT16 modules do not offer the RTS parameter. With these modules, the channel sampling rate is exclusively determined by the RPI value.

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At the RPI, the following events occur.

1. The module scans its channels for input data.

2. The module broadcasts the data to its backplane.

The input module broadcasts data to the chassis backplane immediately after the scan:

• When the module resides in the local chassis, the controller receives the data immediately.

• When the module resides in a remote chassis, the time that is elapsed before the controller receives it depends on the configuration of the network that connects the local and remote chassis.

For more information, see Input Modules in a Remote Chassis.

Input Modules in a Local Chassis

When an input module resides in a local chassis (see Configure a Module on page 17) and after the input module broadcasts data to the chassis backplane, the controller receives it immediately. The analog input module broadcasts data using Multicast as its connection method in a local chassis.

On-Board Memory

Status Data

Channel Data

Channel Data

Channel Data

Channel Data

Channel Data

Channel Data

Ch 0

Ch 1

Ch 2

Ch 3

Ch 4

Ch 5

Timestamp

Channel Data

Channel Data Ch 6

Ch 7 20 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016

Input Modules in a Remote Chassis

When an input module resides in a remote chassis (see Configure a Module on page 17), it is considered remote input module.

At the RPI, the following events occur.

1. The remote input module scans its channels for input data.

2. The remote input module broadcasts the data to its backplane.

3. The network communication module in the chassis with the I/O module sends the data over the network to the controller.

Broadcast Method

The analog input module broadcasts data by using one of the following connection methods:

• Multicast - Data is sent to all network devices at once

• Unicast - Data is sent to a specific controller depending on the configuration of the module

For more information on guidelines for specifying RPI rates, see the Logix5000™ Controllers Design Considerations Reference Manual, publication

1756-RM094.

Trigger Event Tasks

ControlLogix analog input modules can trigger an Event task. The Event task causes the controller to execute a section of logic immediately when a triggering event occurs. You can configure the Event task to be triggered if new input data is sent at the RPI.

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The following graphic shows an Event task dialog box in Logix Designer application.

Event tasks are useful for synchronizing process variable (PV) samples and proportional integral derivative (PID) calculations.

For more information on Event tasks, see the Logix5000™ Controllers Tasks, Programs, and Routines Programming Manual, publication 1756-PM005.

Output Module Operation The RPI defines when a controller sends data to the analog output module and when the output module echoes data. The controller sends data to an output module only at the RPI.

When an output module receives new data from the controller, the module multicasts or ‘echoes’ a data value that corresponds to the signal present at its terminals to the rest of the control system. This feature, called Data Echo, occurs whether the output module resides in the local or remote chassis.

Depending on the value of the RPI, regarding the length of the controller program scan, the output module can receive and ‘echo’ data multiple times during one program scan.

When the RPI is less than the program scan length, the module’s output channels can change values multiple times during one program scan. The controller does not depend on reaching the end of the program to send data.

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Output Modules in a Local Chassis

When an output module resides in a local chassis (see Configure a Module on page 17), it receives data almost immediately after the owner-controller sends it.

The analog output module broadcasts data using Multicast as its connection method in a local chassis.

Output Modules in a Remote Chassis

When an output module resides in a remote chassis (see Configure a Module on page 17), and is connected to the local chassis via an EtherNet/IP network, the following events occur for the controller to send data to the output module.

1. The controller broadcasts data to its local chassis at one of the following events:

• RPI value

• A programmed Immediate Output (IOT) instruction is executed.

An IOT sends data immediately and resets the RPI timer.

2. The 1756 ControlLogix EtherNet/IP communication module in the local chassis broadcasts the data over the EtherNet/IP network.

3. After receiving the output data, the 1756 ControlLogix EtherNet/IP communication in the remote chassis broadcasts the data to its backplane, that is, the remote chassis.

4. The output module receives the data almost immediately after it is broadcast to the remote chassis backplane.

Broadcast Method

The analog output module broadcasts data by using one of the following connection methods:

• Multicast - Data is sent to all network devices at once

• Unicast - Data is sent to a specific controller depending on the module’s configuration

For more information on guidelines for specifying RPI rates, see the Logix5000™ Controllers Design Considerations Reference Manual, publication

1756-RM094.

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Listen-only Mode Any controller in the system can listen to the data from any I/O module, that is, input data or echoed output data, even if the controller does not own the module.

During the I/O configuration process, you can specify a Listen-Only connection.

For more information on Connection options when configuring your system, see page 124.

When you choose a Listen-Only connection, the controller and module establish communication without the configuration data being sent by the controller. In this instance, another controller owns the I/O module.

IMPORTANT The Listen-Only controller receives data from the I/O module as long as an owning connection between a controller and I/O module is maintained.

If the connection between all owner-controllers and the module is broken, the module stops sending data and connections to all `Listening controllers’ are also broken.

In addition, multicast Listen Only connections require at least one multicast owning connection to be active.

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Chapter 2

Analog I/O Module Features

ControlLogix® analog input modules convert an analog signal to a digital value.

The following are example analog signal types to which input modules convert to digital values:

• Volts

• Millivolts

• Milliamps

• Ohms

ControlLogix analog output modules convert a digital value to an analog signal.

The following are example analog signal types to which output modules convert digital values:

• Volts

• Milliamps

Topic Page

Common Analog I/O Features 26

Relationship between Module Resolution and Scaling 35

Calibration 37

Calibrated Accuracy 38

Error Calculated over Hardware Range 38

RTD and Thermocouple Error Calculations 38

Thermocouple Resolution 42 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 25

Chapter 2 Analog I/O Module Features Common Analog I/O Features The ControlLogix analog I/O modules have the following features:

• CIP Sync Timestamp of Data

• Rolling Timestamp of Data

• Floating Point Data Format

• Module Quality Reporting

• Calibration

• Fault and Status Reporting

• Configurable Software

• Latching of Alarms

• Module Inhibiting

• Electronic Keying

• Elegant Migration Emulation Mode

CIP Sync Timestamp of Data

The control system uses a 64-bit system clock. The modules support CIP Sync timestamping by using the 1588 protocol passed throughout the system. The 1588 protocol is defined in the IEEE 1588-2002 standard, publication Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems.

Each input channel scan or new output application is stamped with a CIP Sync timestamp and one timestamp is returned to the controller for the module with the input data transfer.

You can use this feature for the following:

• To identify the sequence of events in fault conditions or during normal operation.

It is possible to use the system clock between multiple modules in the same chassis or throughout a system in which a common Time Master is used.

• To measure the change between samples–which correlates closely with the RPI if no samples are missed in the logic–and to detect when a new sample is available for processing via the logic.

You can also use the 1588 Protocol to synchronize sampling for modules across the entire system. By using the Synchronized Sampling feature, described in detail on page 56 and page 78, you can configure multiple modules to coordinate their input samples precisely with each other when using the same RPI.

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Analog I/O Module Features Chapter 2 Synchronized Sampling lets you configure a test stand, for example, and take many measurements simultaneously across many modules, if needed, while still precisely coordinating the sampling. With these modules, the synchronized sampling should coordinate within approximately ± 20 μs.

Rolling Timestamp of Data

The rolling timestamp is a continuously running 16-bit rolling timestamp that counts in milliseconds from 0…32,767 ms; where 1 ms = 1 count.

Rolling Timestamp with Input Modules

The 1756-IF8I, 1756-IRT8I, 1756-IR12, and 1756-IT16 modules scan their inputs at the RPI, update the input data, and update the rolling timestamp value.

Other ControlLogix analog input modules scan their inputs at the RTS, not the

RPI.

In either case, though, program the controller to use the last two rolling timestamp values to calculate the interval between the receipt of data or the time at which new data is received.

The rolling value is commonly used with instructions such as the PID and PIDE instructions. Every time a rolling timestamp changes, a PID or PIDE instruction is executed. When you configure a PID instruction for use with an input module, set the loop update time equal to the module’s RPI value.

Rolling Timestamp with Output Modules

For the 1756-OF8I module, the rolling timestamp value is updated only when new values are applied to the Digital to Analog Converter (DAC).

Floating Point Data Format

The modules return channel data to the owner-controller in the IEEE 32-bit floating point data format. In your Logix Designer application, the data type is REAL. You can configure the module to scan its channels and return data as quickly as every 1 ms.

The floating point data format lets you change the data representation of the selected channel. Although the full range of the module does not change, you can scale your module to represent I/O data in specific terms for your application.

To scale a channel, select two points that represent signal units, that is, a Low Signal and a High Signal. You also select two points that represent engineering units, that is, Low Engineering and High Engineering.

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The Low Signal point equates to the Low Engineering point and the High Signal point matches the High Engineering point.

By default, module channels that are used in Current mode are scaled such that 4…20 mA equate to 0…100% engineering units. Other module channels scale 1:1 regarding signal units and engineering units by default.

Module Quality Reporting

The modules indicate the quality of channel data returned to the owner-controller. Data quality represents accuracy. There are levels of data quality reported via module input tags.

The following input tags indicate the level of data quality. In the tag names, x represents the module channel number:

• I.Ch[x].Fault tag - This tag indicates that channel data can be completely inaccurate and cannot be trusted for use in the application. If the tag is set to 1, you cannot trust the data reported. You must troubleshoot the module to correct the cause of the inaccuracy.

Common causes of inaccurate data include the following:

– An overrange or underrange condition exists.

– A wire off detection condition has occurred.

– A short circuit detection condition has occurred.

• I.Ch[x].Uncertain tag - This tag indicates that channel data can be inaccurate but it is not known to what degree of inaccuracy. We recommend that you do not use the data for control.

If the tag is set to 1, you know that the data can be inaccurate but you must troubleshoot the module to discover what degree of inaccuracy exists.

EXAMPLE A 1756-IF8I module that is used in current mode maintains 0…21 mA range capability. Your application uses a 4…20 mA transmitter.

• If you want to receive values in signal units, configure the module as follows:

– Low Signal = 4 mA

– High Signal = 20 mA

– Low Engineering = 4 EU

– High Engineering = 20 EU

• If you want to receive values in terms of Percent of Full Scale, configure the module as follows:

– Low Signal = 4 mA

– High Signal = 20 mA

– Low Engineering = 0%

– High Engineering = 100% 28 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016

Common causes of uncertain data include the following:

– The channel is actively being calibrated.

– An invalid sensor offset value exists.

– The last data sample of the channel failed the CRC check between the module processor and the Analog to Digital Converter (ADC) which results in the most recent valid data sample was used.

– The channel is not calibrated.

We recommend that you monitor these tags in your program to make sure that the application is operating as expected with accurate channel input data.

Calibration

These modules use precise analog components that maintain their specifications over time. The modules are calibrated at the factory and recalibration is not required.

If desired, you can recalibrate the modules on a channel-by-channel or module-wide basis. For more information, see Calibrated Accuracy on page 38 if you choose to recalibrate the modules in the future.

Fault and Status Reporting

The modules provide fault and status data along with channel data. Faults are indicated via the status indicators on the front of the module and the module tags. Status data is available via the module tags.

• For more information on fault and status reporting via module tags, see the following:

– 1756-IF8I fault and status reporting - page 62

– 1756-IRT8I fault and status reporting - page 92

– 1756-IR12 fault and status reporting - page 92

– 1756-IT16 fault and status reporting - page 92

– 1756-OF8I fault and status reporting - page 101

• For more information on fault reporting via status indicators, see Chapter 9, Troubleshoot Your Module on page 159 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 29

Configurable Software

Use one of the following software applications with your module:

• RSLogix 5000® software, versions 18…20

• Logix Designer application, version 21 or later

All module feature configuration begins in the I/O configuration portion of the Logix Designer application. In addition, to enable or disable module features, you can use the application to interrogate any module for the following module information:

• Serial number

• Revision information

• Catalog number

• Vendor identification

• Error/fault information

• Diagnostic counters

Latching of Alarms

This feature latches a module alarm in the set position once the alarm is triggered.

The alarm remains on, even if the condition that causes it to occur disappears, until the alarm is unlatched.

To see where to latch alarms, see page 131.

IMPORTANT You must install Add-on Profiles (AOP) to use the modules in any Logix Designer application or RSLogix 5000 software project.

This publication describes configuration with Logix Designer application. AOPs are available at:

https://download.rockwellautomation.com/esd/ download.aspx?downloadid=addonprofiles

IMPORTANT You must manually unlatch the alarm. You can unlatch the alarm by using one of the following methods:

• While the project is online, click the Alarm Configuration tab on the Module. Then click

Unlatch to unlatch a specific alarm or Unlatch All to unlatch all alarms.

• Change the module output tag for the alarm that you want to unlatch. For example, the

Ch[x].LLAlarmUnlatch tag to unlatch a Low Low Alarm.

For more information on module tags, see Appendix A, Analog I/O Module Tag Definitions on page 175.

• Use a CIP Generic message.

For more information how to use a CIP Generic message, see Rockwell Automation® Knowledgebase article #63046, How to Reset Latched Status of an Analog Module. You can access the article at: (Login required) https://rockwellautomation.custhelp.com/ 30 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 https://download.rockwellautomation.com/esd/download.aspx?downloadid=addonprofiles https://download.rockwellautomation.com/esd/download.aspx?downloadid=addonprofiles https://rockwellautomation.custhelp.com/

Module Inhibiting

This feature suspends the connection between an owner-controller and a module. This process can occur in either of the following ways:

• You write configuration for an I/O module but inhibit the module to prevent it from communicating with the owner-controller.

In this case, the owner does not establish a connection and configuration is not sent to the module until the connection is uninhibited.

• A controller owns a module and has downloaded configuration to it. Data is being exchanged over the connection between the devices.

In this case, when you inhibit the module and the owner-controller behaves as if the connection to the module does not exist.

The following examples are instances where you need to use module inhibiting:

• Multiple controllers own an analog input module. A configuration change is required. You must make the change in the program in all controllers. In this case, complete the following tasks.

a. Inhibit the module.

b. Change configuration in all controllers.

c. Uninhibit the module.

• You want to upgrade the module. We recommend that you complete the following tasks.

a. Inhibit the module.

b. Perform the upgrade.

c. Uninhibit the module.

• The program includes a module that you do not physically possess and you do not want the controller to continually look for a module that does not exist.

Inhibit the module until it physically resides in the proper slot. To see where to inhibit a module connection, see page 124.

IMPORTANT Whenever you inhibit an output module, it enters Program mode and all outputs change to the state configured for the Program mode. For example, if an output module is configured so that the states of the outputs go to zero (0) during Program mode, whenever that module is inhibited, the outputs go to zero (0).

Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 31

Electronic Keying

Electronic Keying reduces the possibility that you use the wrong device in a control system. It compares the device defined in your project to the installed device. If keying fails, a fault occurs. These attributes are compared.

The following Electronic Keying options are available.

Carefully consider the implications of each keying option when selecting one.

More Information

For more detailed information on Electronic Keying, see Electronic Keying in Logix5000 Control Systems Application Technique, publication LOGIX-AT001.

Attribute Description

Vendor The device manufacturer.

Device Type The general type of the product, for example, digital I/O module.

Product Code The specific type of the product. The Product Code maps to a catalog number.

Major Revision A number that represents the functional capabilities of a device.

Minor Revision A number that represents behavior changes in the device.

Keying Option Description

Compatible Module

Lets the installed device accept the key of the device that is defined in the project when the installed device can emulate the defined device. With Compatible Module, you can typically replace a device with another device that has the following characteristics:

• Same catalog number

• Same or higher Major Revision

• Minor Revision as follows:

– If the Major Revision is the same, the Minor Revision must be the same or higher.

– If the Major Revision is higher, the Minor Revision can be any number.

Disable Keying Indicates that the keying attributes are not considered when attempting to communicate with a device. With Disable Keying, communication can occur with a device other than the type specified in the project.

ATTENTION: Be extremely cautious when using Disable Keying; if used incorrectly, this option can lead to personal injury or death, property damage, or economic loss.

We strongly recommend that you do not use Disable Keying.

If you use Disable Keying, you must take full responsibility for understanding whether the device being used can fulfill the functional requirements of the application.

Exact Match Indicates that all keying attributes must match to establish communication. If any attribute does not match precisely, communication with the device does not occur.

IMPORTANT Changing Electronic Keying parameters online interrupts connections to the device and any devices that are connected through the device.

Connections from other controllers can also be broken.

If an I/O connection to a device is interrupted, the result can be a loss of data.

32 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 http://literature.rockwellautomation.com/idc/groups/literature/documents/at/logix-at001_-en-p.pdf

Elegant Migration Emulation Mode

The 1756 Isolated Analog I/O modules, which are 6-channel, have a migration path to the 1756 Isolated Analog 8-channel modules. Table 2 shows the relationship between the 6-channel modules and the 8-channel modules.

The migration catalog numbers, (1756-IF8I, 1756-IRT8I, and 1756-OF8I), firmware revision 2.011 and later can communicate to the controller as if they are 6-channel modules. This Emulation mode lets a 6-channel module application migrate to use the 8-channel module.

This migration means that when a forward open containing configuration data is sent to the 8-channel module, it can accept it and respond as if it were a 6-channel module. After the connection is established, all data (input and/or output) is sent to/from the controller in the same format and tag structures as if it were a 6-channel module. With this method, you can directly replace a 6-channel module with an 8-channel module with no I/O tree modifications or program changes.

When an 8-channel module receives configuration data for a 6-channel module, the 8-channel module takes that information and reformats it to replicate the configuration data of an 8-channel module. The 8-channel module scans the firmware but reformats the input and/or output data to match the 6-channel module.

In general, the 8-channel module is internally behaving as an 8-channel module because most of the firmware has not changed. The difference in 8-channel module firmware is that in emulation mode, configuration, input, and output data is reformatted to match the appropriate 6-channel module.

All data to/from an 8-channel module is mapped from a 6-channel module format to an 8-channel module format. The controller still sends data in the 1756-IF6I module format but firmware internally moves data to the 1756-IF8I module format.

Table 2 - 1756-Isolated Analog I/O Module Migration Descriptions

Catalog Number 1756 ControlLogix Isolated Analog I/O 6-channel Description

Migration Catalog Number 1756 ControlLogix Isolated Analog I/O 8-channel Description

1756-IF6I Isolated Analog Input-Current/Voltage 6 Pts (20 Pin) 1756-IF8I Analog Input Module, 8 Isolated Points, Current, Current Sourcing and Voltage (36 Pin)

1756-IF6CIS Isolated Analog In-Current Sourcing 6 Pts (20 Pin)

1756-IT6I Isolated Thermocouple/Mv Input 6 Pts (20 Pin) 1756-IRT8I RTD / Ohms / Thermocouple / mV Input Module, 8 Individually Configurable Isolated Points (36 Pin)

1756-IT6I2 Enhanced Isolated Thermocouple/Mv Input 6 Pts (20 Pin)

1756-IR6I Isolated RTD Input 6 Pts (20 Pin)

1756-OF6VI Isolated Analog Output - Voltage 6 Pts (20 Pin) 1756-OF8I Analog Output Module, 8 Isolated Points, Current and Voltage (36 Pin)

1756-OF6CI Isolated Analog Output - Current 6 Pts (20 Pin) Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 33

Figure 2 - 1756-IF6I Module Configuration Example

For more information, see Migrating from 6 Channel 1756 Analog Modules to 8 Channel 1756 Analog Modules, publication 1756-RM011.

1756-IF6I module configuration data sent to the 1756-IF8I module. Internally, the 1756-IF8I module sees the data like this.

1756-IF6I Module Configuration Example The Controller still sends data in the 1756-IF6I module format but firmware internally moves data to the 1756-IF8I format. An 8-channel module still behaves as an 8-channel module, but accepts a 6-channel module format.

34 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm011_-en-e.pdf

Relationship between Module Resolution and Scaling

The following concepts must be explained with each other:

• Module Resolution

• Scaling

Module Resolution

Resolution is the smallest degree of change that the module is capable of detecting. Module resolution represents a fixed number of counts across the module’s theoretical operating range.

• 1756-IF8I and 1756-IRT8I modules support 24-bit resolution.

The 24 bits represent 16,777,216 counts.

• 1756-OF8I module supports 16-bit resolution.

The 16 bits represent 65,536 counts.

• 1756-IR12 module supports 24-bit resolution.

• 1756-IT16 module supports 24-bit resolution.

Resolution on Input Modules

The theoretical operating range is the full range across which the module can operate. For example, a 1756-IF8I module in Current mode has a theoretical operating range = -25.1…25.1 mA. The 24-bit resolution and 16,777,216 counts are available across 50.2 mA, which yields our calculated 2.99 nA/count resolution.

However, when the 1756-IF8I module operates in Current mode, it is configured for an input range = 0…20 mA. This range limits the input to a 0…21 mA actual range capability.

The number of counts on a module is fixed. Module actual range capabilities, however, narrow operating ranges from the theoretical and result in supporting fewer counts. Using the example above, the 0…21 mA actual range capability represents 5,815,117 counts, that is, slightly more than 22.5 bits.

Divide the actual range capability by the number of counts in that range to determine the value of each count. The input range that you choose during module configuration determines the value of each count. It does not determine the number of counts in that range. Therefore, module resolution across the usable input operating range is not always 24 bits.

Rockwell Automation Publication 1756-UM540D-EN-P - April 2016 35

Resolution on Output Module

The module resolution for the 1756-OF8I module is always 16 bits, regardless of operating mode and operating range.

The following table lists the resolution for each module’s input/output range and corresponding range capability.

Scaling

When scaling, you choose two points along the module’s operating range and apply low and high values to those points.

For example, if you are using the 1756-IF8I module in Current mode, the module supports a 0…21 mA actual range capability. But your application uses a 4…20 mA transmitter. Scaling lets you configure the module to return data to the controller so that a low signal value of 4 mA returns a low engineering value of 0% and a high signal value of 20 mA returns a high engineering value of 100%.

Table 3 - Module Resolution in Various Configuration Selections

Module Mode Available Input/ Output Range(1)

Actual Input/Output Range Capability

Number of Bits Across the Theoretical Operating Range

Number of Bits Across the Actual Range Capability

Resolution (signal per count)

1756-IF8I

Voltage -10…10V 0…10V 0…5V

-10.5…10.5V 0…10.5V 0…5.25V 24 bits

23.75 22.75 21.75

1.49 μV/count

Current 0…20 mA 0…20 mA (sourcing)

0…21 mA 0…21 mA (sourcing)

22.74

2.99 nA/count

1756-IRT8I

1756-IT16

Thermocouple -100…100 mV -101…101 mV

24 bits

23.98

0.01 μV/count

1756-IRT8I

1756-IR12

RTD

1…500 Ω 2…1000 Ω 4…2000 Ω 8…4000 Ω

0…510 Ω 0…1020 Ω 0…2040 Ω 0…4080 Ω

23.98

0.06 mΩ/count

0.12 mΩ/count

0.25 mΩ/count

0.50 mΩ/count

1756-OF8I

Voltage

-10…10V 0…10V 0…5V

-10.5…10.5V 0…10.5V 0…5.25V 16 bits

16.00

0.32 mV/count

0.16 mV/count

0.08 mV/count

Current 0…20 mA 0…21 mA 16.00 0.32 μA

(1) These ranges represent the range choices available in the Logix Designer application.

IMPORTANT Because these modules must allow for possible calibration inaccuracies, resolution values represent the available Analog-to-Digital or Digital-to- Analog counts over the specified range.

Additionally, RPI and Notch Filter settings affect module resolution on the 1756-IF8I and 1756-IRT8I modules. For more information, see page 47 and page 65, respectively.

36 Rockwell Automation Publication 1756-UM540D-EN-P - April 2016

The returned engineering unit’s value is indicated in the I.Ch[x].Data tag as shown in Table 4.

Figure 3 - Module Resolution Compared to Module Scaling

The module can operate with values beyond…