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