Rockwell Automation 1746-NT4 User Manual

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SLC

™

500 4-Channel Thermocouple/mV Input Module

(Catalog Number 1746-NT4, Series B)

User Manual

Important User Information

Solid state equipment has operational characteristics differing from those of electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (Publication SGI-1.1 available from your local Rockwell Automation sales office or online at http://www.ab.com/manuals/gi) describes some important differences between solid state equipment and hard-wired electromechanical devices. Because of this difference, and also because of the wide variety of uses for solid state equipment, all persons responsible for applying this equipment must satisfy themselves that each intended application of this equipment is acceptable.

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 we use notes to make you aware of safety considerations.

WARNING

IMPORTANT

ATTENTION

SHOCK HAZARD

BURN HAZARD

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.

Identifies information that is critical for successful application and understanding of the product.

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

• recognize the consequence

Labels may be located on or inside the drive to alert people that dangerous voltage may be present.

Labels may be located on or inside the drive to alert people that surfaces may be dangerous temperatures.

Summary of Changes

The information below summarizes the changes to this manual since the last printing.

To help you find new and updated information in this release of the manual, we have included change bars as shown to the right of this paragraph.

For information on: See page:

Changes to the SLC™ 500 Thermocouple/mV Input Module. throughout manual Using RSLogix™ 500 to configure the NT4 module. 2-4, 5-2, 6-1, and Appendix

Maintaining the ambient temperature surrounding the SLC 500 above 3°C (37.4°F).

A-2

Publication 1746-UM007C-EN-P - July 2004

2 Summary of Changes

Publication 1746-UM007C-EN-P - July 2004

Overview

Quick Start for Experienced Users

Preface

Who Should Use this Manual. . . . . . . . . . . . . . . . . . . . . . . P-1

Purpose of this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . P-1

Related Documentation . . . . . . . . . . . . . . . . . . . . . . . . P-2

Your Questions or Comments on this Manual . . . . . . . . P-3

Common Techniques Used in this Manual . . . . . . . . . . . . . P-3

Chapter 1

General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Hardware Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

General Diagnostic Features. . . . . . . . . . . . . . . . . . . . . 1-3

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Module Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Thermocouple Compatibility . . . . . . . . . . . . . . . . . . . . 1-5

Linear Millivolt Device Compatibility. . . . . . . . . . . . . . . 1-7

Chapter 2

Required Tools and Equipment . . . . . . . . . . . . . . . . . . . . . 2-1

Installation Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Installation and Wiring

Preliminary Operating Considerations

Chapter 3

Compliance to European Union Directives . . . . . . . . . . . . . 3-1

EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Electrostatic Discharge. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

NT4 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Module Location in Chassis . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Fixed Expansion Chassis Considerations . . . . . . . . . . . . 3-3

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Module Installation and Removal. . . . . . . . . . . . . . . . . . . . 3-5

Terminal Block Removal . . . . . . . . . . . . . . . . . . . . . . . 3-6

Module Installation Procedure . . . . . . . . . . . . . . . . . . . 3-6

Module Removal Procedure . . . . . . . . . . . . . . . . . . . . . 3-7

Terminal Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Wiring Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

Wiring Input Devices to the NT4 . . . . . . . . . . . . . . . . . 3-11

Cold Junction Compensation (CJC) . . . . . . . . . . . . . . . . 3-12

Thermocouple Calibration . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

Chapter 4

Module ID Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Module Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Output Image-Configuration Words . . . . . . . . . . . . . . . 4-2

Input Image-Data Words and Status Words . . . . . . . . . . 4-3

Channel Filter Frequency Selection . . . . . . . . . . . . . . . . . . 4-4

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Table of Contents ii

Channel Configuration, Data, and Status

Effective Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Channel Cut-Off Frequency . . . . . . . . . . . . . . . . . . . . . 4-5

Channel Step Response . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Update Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Update Time Calculation Example . . . . . . . . . . . . . . . . 4-8

Channel Turn-On, Turn-Off, and Reconfiguration Times . . . 4-9

Response to Slot Disabling . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Input Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Output Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Chapter 5

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Channel Configuration Procedure . . . . . . . . . . . . . . . . . . . 5-2

Select Input Type (Bits 0-3) . . . . . . . . . . . . . . . . . . . . . 5-5

Select Data Format (Bits 4 and 5) . . . . . . . . . . . . . . . . . 5-5

Using Scaled-for-PID and Proportional Counts . . . . . . . 5-6

Scaling Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

Select Open Circuit State (Bits 6 and 7). . . . . . . . . . . . . 5-10

Select Temperature Units (Bit 8) . . . . . . . . . . . . . . . . . . 5-11

Select Channel Filter Frequency (Bits 9 and 10). . . . . . . 5-11

Select Channel Enable (Bit 11) . . . . . . . . . . . . . . . . . . . 5-12

Unused Bits (Bits 12-15). . . . . . . . . . . . . . . . . . . . . . . . 5-12

Channel Data Word. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12

Channel Status Checking . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13

Status Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15

Input Type Status (Bits 0-3) . . . . . . . . . . . . . . . . . . . . . 5-15

Data Format Type Status (Bits 4 and 5). . . . . . . . . . . . . 5-15

Open Circuit Type Status (Bits 6 and 7) . . . . . . . . . . . . 5-15

Temperature Units Type Status (Bit 8). . . . . . . . . . . . . . 5-16

Channel Filter Frequency (Bits 9 and 10) . . . . . . . . . . . 5-16

Channel Status (Bit 11). . . . . . . . . . . . . . . . . . . . . . . . . 5-16

Open-Circuit Error (Bit 12) . . . . . . . . . . . . . . . . . . . . . . 5-16

Under-Range Error (Bit 13). . . . . . . . . . . . . . . . . . . . . . 5-16

Over-Range Error (Bit 14). . . . . . . . . . . . . . . . . . . . . . . 5-17

Configuration Error (Bit 15) . . . . . . . . . . . . . . . . . . . . . 5-17

Ladder Programming Examples

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Chapter 6

Initial Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Dynamic Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Verifying Channel Configuration Changes . . . . . . . . . . . . . 6-4

Interfacing to the PID Instruction. . . . . . . . . . . . . . . . . . . . 6-5

Monitoring Channel Status Bits . . . . . . . . . . . . . . . . . . . . . 6-6

Invoking Autocalibration . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Module Diagnostics and Troubleshooting

Application Examples

Table of Contents iii

Chapter 7

Module Operation vs Channel Operation . . . . . . . . . . . . . . 7-1

Power-up Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Channel Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Channel Status LEDs (Green) . . . . . . . . . . . . . . . . . . . . 7-4

Invalid Channel Configuration . . . . . . . . . . . . . . . . . . . 7-4

Open Circuit Detection . . . . . . . . . . . . . . . . . . . . . . . . 7-4

Out-Of-Range Detection. . . . . . . . . . . . . . . . . . . . . . . . 7-5

Module Status LED (Green) . . . . . . . . . . . . . . . . . . . . . 7-5

Troubleshooting Flowchart . . . . . . . . . . . . . . . . . . . . . . . . 7-6

Replacement Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7

Contacting Rockwell Automation . . . . . . . . . . . . . . . . . . . . 7-7

Chapter 8

Basic Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

Application Setup (Display a Temperature) . . . . . . . . . 8-1

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

Supplementary Example . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

Application Setup (Four Channels °C - °F) . . . . . . . . . . 8-4

Device Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

Program Setup and Operation Summary . . . . . . . . . . . . 8-7

Program Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

Specifications

NT4 Configuration Worksheet

Thermocouple Restrictions

Appendix A

Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Physical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . A-2

Input Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3

1746-NT4 Module Accuracy . . . . . . . . . . . . . . . . . . . . . A-4

Input Resolution per Thermocouple Type at Each Filter

Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Appendix B

Channel Configuration Procedure . . . . . . . . . . . . . . . . . . . B-1

Channel Configuration Worksheet . . . . . . . . . . . . . . . . . . . B-4

Appendix C

J Type Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

(Iron vs. Copper-Nickel <Constantan>) . . . . . . . . . . . . . C-1

K Type Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

(NIckel-Chromium vs. Nickel-Aluminum) . . . . . . . . . . . C-2

T Type Thermocouple. . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3

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Table of Contents iv

Thermocouple Types

Configuring the 1746-NT4 Module with RSLogix 500

(Copper vs. Copper-Nickel <Constantan>) . . . . . . . . . . C-3

E Type Thermocouple. . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

(Nickel-Chromium vs. Copper-Nickel <Constantan>) . . . C-4

S and R Type Thermocouples . . . . . . . . . . . . . . . . . . . . . . C-5

S (Platinum-10% Rhodium vs. Platinum)

R (Platinum-13% Rhodium vs. Platinum) . . . . . . . . . . . C-5

Appendix D

Appendix E

Glossary

Index

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Preface

Read this preface to familiarize yourself with the rest of the manual. The preface includes:

• Who Should Use this Manual

• Purpose of this Manual

• Common Techniques Used in this Manual

Who Should Use this Manual

Purpose of this Manual

Use this manual if you are responsible for designing, installing, programming, or troubleshooting control systems that use SLC 500 4-Channel Thermocouple/mV Input Module.

You should have a basic understanding of electrical circuitry and familiarity with relay logic. If you do not, obtain the proper training before using this product.

This manual describes the procedures you use to install, wire, and troubleshoot your 4-channel thermocouple/mV module. This manual:

• explains how to install and wire your module

• gives you an overview of the SLC 500 programmable controller

system

Refer to your programming software user documentation for more information on programming your SLC 500 programmable controller.

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2 Preface

Overview

This chapter describes the thermocouple/millivolt module and explains how the SLC controller gathers thermocouple or millivolt initiated analog input from the module. This chapter includes:

• General Description

• System Overview

General Description

The thermocouple/mV module receives and stores digitally converted thermocouple and/or millivolt (mV) analog data into its image table for retrieval by all fixed and modular SLC 500 processors. The module supports connections from any combination of up to four thermocouple or mV analog sensors.

The following tables define thermocouple types and their associated full scale temperature ranges and also list the millivolt analog input signal ranges that each 1746-NT4 channel will support. To determine the practical temperature range your thermocouple supports, refer to the specifications in Appendix A.

Ty pe °C Temperature Range °F Temperature Range J -210° to 760° -346° to 1400° K -270° to 1370° -454° to 2498° T -270° to 400° -454° to 752° B 300° to 1820° 572° to 3308° E -270° to 1000° -454° to 1832° R 0° to 1768° 32° to 3214° S 0° to 1768° 32° to 3214° N 0° to 1300° 32° to 2372° CJC Sensor 0° to 85° 32° to 185°

Millivolt Input Type Range

±50 mV -50 mV dc to +50 mV dc ±100 mV -100 mV dc to +100 mV dc

Each input channel is individually configurable for a specific input device and provides open-circuit, over-range, and under-range detection and indication.

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1-2 Overview

Hardware Features

The thermocouple module fits into any single-slot, except the processor slot (0), in either an SLC 500 modular system or an SLC 500 fixed system expansion chassis (1746-A2). It is a Class 1 module (uses 8 input words and 8 output words). It interfaces to thermocouple types J, K, T, E, R, S, B, and N, and supports direct ±50 mV and ±100 mV analog input signals.

The module requires the use of Block Transfer in a remote configuration.

The module contains a removable terminal block providing connection for four thermocouple and/or analog input devices. There are also two, cold-junction compensation (CJC) sensors used to compensate for offset voltages introduced into the input signal as a result of the cold-junction, i.e., where the thermocouple wires connect to the module wiring terminal. There are no output channels on the module. Module configuration is done via the user program. There are no DIP switches.

Channel Status LEDs (Green)

Module Status LED (Green)

Removable Terminal Block

CJC Sensors

Cable Tie Slots

INPUT

CHANNEL STATUS

MODULE

ATUS

THERMOCOUPLE/mV

012

Door Label

CJC A+ Do Not Remove

CHL0+

CJC A Do Not Remove

CHL0

SHIELD

CHL1+

SHIELD

CHL1

SHIELD

CHL2+

SHIELD

CHL2

SHIELD

CHL3+

CJC B Do Not

CHL3

Remove CJC B+

Do Not Remove

ANLG COM

Side Label

CAT

SERIAL

1746 NT4

NT4-xxx x

THERMOCOUPLE/mV INPUT MODULE

SLC 500

NO.

SER

FRN

CLASS I, GROUPS A, B, C AND D, DIV.2

FOR HAZ. LOC. A196

LISTED IND. CONT. EQ.

OPERATING

TEMPERATURE

CODE T3C

FAC 1M

THERMOCOUPLE TYPES:

VOLTAGE:

INPUT SIGNAL RANGES

100mVDC to +100mVDC

50mVDC to +50mVDC

J, K, T, E, R, S, B, N

MADE IN USA

Self-Locking Tabs

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Hardware Function

Overview 1-3

Channel Status LED Indicators

Module Status LED Displays module operating and fault status Side Label (Nameplate) Provides module information Removable Terminal Block Provides physical 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

Display operating and fault status of channels 0, 1, 2, and 3

It is color coded green.

General Diagnostic Features

The thermocouple/mV module contains diagnostic features that can help you identify the source of problems that may occur during power-up or during normal channel operation. These power-up and channel diagnostics are explained in chapter 7, Module Diagnostics and Troubleshooting.

System Overview

The thermocouple module communicates to the SLC 500 processor through the parallel backplane interface and receives +5V dc and +24V dc power from the SLC 500 power supply through the backplane. No external power supply is required. You may install as many thermocouple modules in your system as the power supply can support.

SLC Processor

Thermocouple Modules

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1-4 Overview

Each individual channel on the thermocouple module can receive input signals from thermocouple sensors or mV analog input devices. You configure each channel to accept either input. When configured for thermocouple input types, the thermocouple module converts the analog input voltages into cold-junction compensated and linearized, digital temperature readings. The 1746-NT4 uses the National Bureau of Standards (NBS) Monograph 125 and 161 based on IPTS-68 for thermocouple linearization.

When configured for millivolt analog inputs, the module converts the analog values directly into digital values. The module assumes that the mV input signal is already linear.

System Operation

At power-up, the thermocouple module performs a check of its internal circuits, memory, and basic functions. During this time the module status LED remains off. If no faults are found during the power-up diagnostics, the module status LED is turned on.

Thermocouple or mV

Analog Signals

Thermocouple

Input

Module

Channel Data W

Channel

Configuration W

Status W

ord

SLC 500

Processor

ord

After power-up checks are complete, the thermocouple module waits for valid channel configuration data from your SLC ladder logic program (channel status LEDs off). After configuration data is written to one or more channel configuration words and their channel enable status bits are set, the channel status LEDs go on and the thermocouple module continuously converts the thermocouple or millivolt input to a value within the range you selected for the enabled channels.

Each time a channel is read by the module, that data value is tested by the module for a fault condition, i.e. open circuit, over range, and under range. If such a condition is detected, a unique bit is set in the channel status word and the channel status LED blinks.

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. The processor and thermocouple module determine that the backplane data transfer was made without error, and the data is used in your ladder program.

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Overview 1-5

Module Operation

The thermocouple module input circuitry consists of four differential analog inputs multiplexed into a single analog-to-digital (A/D) convertor. The mux circuitry also continuously samples the CJC A and CJC B sensors and compensates for temperature changes at the cold junction (terminal block). The figure on the following page shows a block diagram for the analog input circuitry.

The A/D convertor reads the selected input signal and converts it to a digital value. The multiplexer sequentially switches each input channel to the module’s A/D convertor. Multiplexing provides an economical means for a single A/D convertor to convert multiple analog signals. However, it does affect the speed at which an input signal can change and still be detected by the convertor.

Thermocouple Compatibility

The thermocouple module is fully compatible with all SLC 500 fixed and modular controllers. It is compatible with all NBS MN-125 standard types J, K, T, E, R, S, and B thermocouple sensors and extension wire; and with NBS MN-161, 14AWG, standard type N thermocouple and extension wire. Refer to Appendix C for more details.

The Series B (or higher) 1746-NT4 differential design allows for a maximum channel-to-channel common-mode voltage difference/separation of 2 volts. This means that if you are using an NT4 with multiple grounded thermocouples with metallic sheaths or exposed thermocouples with measuring junctions that make contact with electrically conductive material, their ground potentials must be within 2 volts. If this is not done, your temperature readings will be inaccurate or the module could be damaged. If your grounded thermocouple protective sheath is made of an electrically non-conductive material such as ceramic, then the voltage separation specification is not as important. Refer to Appendix D for an explanation of grounded, ungrounded, and exposed thermocouples.

Use the analog common (

ANALOG COM) terminal for applications that

have multiple grounded thermocouples. This analog common terminal must be jumpered to either the (+) or (-) terminal of any active channel which is connected to a grounded thermocouple. See Wiring Considerations on page 3-8 for complete information on the use of the

ANALOG COM terminal.

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1-6 Overview

Input Circuit Block Diagram

Terminal Block Module Circuitry

CJCA

Sensor

Open Circuit

Detection

within

2V*

within

2V*

*See Important note below.

Channel 0

Channel

ungrounded thermocouple

grounded thermocouple

user supplied jumper

CJCB Sensor

Shield

Analog

Common

Multiplexer

Analog to

Digital

Convertor

User-Selected

Filter Frequency

Digital

Filter

Digital Value

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Chassis Ground (internally connected)

IMPORTANT

When using multiple grounded and/or exposed thermocouples that are touching on electrically conductive material with Series B or higher 1746-NT4, the ground potential between any two channels cannot exceed 2 volts.

Overview 1-7

ATTENTION

The possibility exists that grounded or exposed thermocouples can become shorted to a potential greater than that of the thermocouple itself. Due to possible shock hazard, care should be taken when wiring these types of thermocouples. Refer to Appendix D for more details.

Linear Millivolt Device Compatibility

A large number of millivolt devices may be used with the 1746-NT4 module. For this reason we do not specify compatibility with any particular device.

However, millivolt applications often use bridges of strain gages. To allow the NT4 Series B (or higher) to operate correctly, the analog common ( level within 2V of the signal of interest. A resistive voltage divider using 10k Ω resistors is recommended to accomplish this. The circuit diagram below shows how this connection is made.

ANALOG COM) terminal of the module needs to be biased to a

NT4

INPUT

(CHL0, CHL1,

CHL2, CHL3)

ANALOG COM

Strain

Gage

Bridge

fixed

Vcc

variable

fixed

10k Ω

10k

Ω

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1-8 Overview

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Chapter

Quick Start for Experienced Users

This chapter can help you to get started using the NT4 4-channel thermocouple/mV module. The procedures are based on the assumption that you have an understanding of SLC 500 products. You should understand electronic process control and be able to interpret the ladder logic instructions required to generate the electronic signals that control your application.

Because it is a start-up guide for experienced users, this chapter does not contain detailed explanations about the procedures listed. It does, however, reference other chapters in this book where you can get more information about applying the procedures described in each step. It also references other documentation that may be helpful if you are unfamiliar with programming techniques or system installation requirements.

Required Tools and Equipment

If you have any questions or are unfamiliar with the terms used or concepts presented in the procedural steps, always read the referenced chapters and other recommended documentation before trying to apply the information.

This chapter includes:

• Required Tools and Equipment

• Installation Procedures

Have the following tools and equipment ready:

• medium blade screwdriver

• medium cross-head screwdriver

• thermocouple or millivolt sensor

• appropriate thermocouple extension wire (if needed)

• 4-channel thermocouple/mV input module (1746-NT4)

• programming equipment

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2-2 Quick Start for Experienced Users

Installation Procedures

1. Check the contents of shipping box. Reference

Unpack the shipping box making sure that the contents include:

• thermocouple input module (Catalog Number 1746-NT4)

• removeable terminal block (factory installed on module) with CJC sensors attached.

• installation instructions (publication 1746-IN010)

If the contents are incomplete, call your local Allen-Bradley representative for assistance.

2. Ensure your chassis supports placement of the 1746-NT4 module Reference

Review the power requirements of your system to see that your chassis supports placement of the thermocouple input module.

• For modular style systems, calculate the total load on the system power supply using the

procedure described in the SLC 500 Modular Hardware Style User Manual (Publication Number 1747-UM011) or the SLC 500 Modular Chassis and Power Supplies Technical Data (Publication Number 1746-TD003).

• The fixed, 2-slot chassis supports 2 thermocouple input modules. If combining a

thermocouple module with a different module, refer to the module compatibility table found in chapter 3.

Chapter 3

(Installion and Wiring

Appendix A

(Specifications)

Publication 1746-UM007C-EN-P - July 2004

Quick Start for Experienced Users 2-3

3. Insert the 1746-NT4 module into the chassis Reference

Make sure system power is off; then insert the thermocouple input module into your 1746 chassis. In this example procedure, local slot 1 is selected.

ATTENTION

Never install, remove, or wire modules with power applied to the chassis or devices wired to the module.

op and Bottom

Module Release(s)

Chapter 3

(Installation and Wiring)

Card Guide

Publication 1746-UM007C-EN-P - July 2004

2-4 Quick Start for Experienced Users

4. Connect the thermocouple wires Reference

Connect thermocouple wires to channel 0 on the module’s terminal block. Make sure both cold junction compensation (CJC) assemblies are securely attached.

Ground the shield drain wire at one end only. The preferred location is to the same point as the sensor ground reference. For grounded thermocouples or mV sensors, this is at the sensor. For insulated/ungrounded thermocouples, this is at the NT4 module.

Terminal

Block

CJC A Assembly

SHIELD SHIELD

CHL 0+

CHL

CHL 1+

CHL

Refer to the paragraph above

Thermocouple Wire

Chapter 3

(Installion and Wiring

Appendix D

(Thermocouple Types

5. Configure the system. Reference

Configure your system I/O configuration for the particular slot the NT4 is in (slot 1 in this example). Select the module from the drop-down list or enter the thermocouple input module ID code (3510).

Chapter 4

(Preliminary Operating Considerations)

When using RSLogix 500 version 6.10 or higher, you may select Advanced Configuration, then Configure, to use the software’s I/O wizard to configure the NT4 (see appendix E for details). If you use this option, proceed to step 8.

Your programming software online help screens

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Quick Start for Experienced Users 2-5

6. Determine the operating parameters. Reference

Determine the operating parameters for channel 0. This example shows the channel 0 configuration word defined with all defaults (0) except for channel enable (bit 11). The addressing reflects the location of the module as slot 1.

SLC 500 Controller Data Files

Output Image

(8 words)

Channel 0 Configuration Word

Channel 1 Configuration W Channel 2 Configuration W Channel 3 Configuration W

ords 4 7

(not defined)

ord ord ord

Unused

emperature Units

Filter Frequency

Channel Enable

Data Format

Open Circuit

000000000000000

Default Setting

Type J Thermocouple

•

Engineering Units x 1

•

Data Word = 0 If Open Circuit

•

Degrees Celsius

•

10 Hz. Filter Frequency

•

Channel Disabled

•

Bit

000010000000000

New Setting

Address

O:1.0 O:1.1 O:1.2 O:1.3

•

O:1.7

Input Image

ord 0

ord 1

ord 2

ord 3

•

ord 7

Chapter 4

(Preliminary Operating Considerations)

Chapter 5

(Channel Configuration, Data, and Status)

Appendix B

(NT4 Configuration Worksheet)

Type Input

Bit 0

Set this bit (11) to enable channel. Address = O:1.0/11.

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2-6 Quick Start for Experienced Users

Program the configuration.

Do the programming necessary to establish the new configuration word setting in the previous step.

1. Create integer file N10. Integer file N10 should contain one element for each channel used. (For this example we only need one, N10:0.)

2. Enter the configuration parameters from step 6 for channel 0 into integer N10:0. In this example all the bits of N10:0 will be zero except for the channel enable (N10:0/11).

3. Program an instruction in your ladder logic to copy the contents of N10:0 to output word O:1.0.

Example of Data Table for Integer File N10:

address N10:0 0000 1000 0000 0000

15 data 0 address 15 data 0

First Pass Bit

S:1

] [

COP COPY FILE Source

# N10:0

Dest # Length 1

O:1.0

On power up, the first pass bit (S:1/15) is set for one scan, enabling the COPY instruction that transfers a one to bit 11 of channel configuration word 0. This enables the channel..

Reference

Chapter 6

(Ladder Programming Examples)

Chapter 8

(Application Examples)

8. Write the ladder program. Reference

Write the remainder of the ladder logic program that specifies how your thermocouple input data will be processed for your application. In this procedure the addressing reflects the location of the module as slot 1.

Chapter 5

(Channel Configuration, Data, and Status)

Chapter 6

(Ladder Programming Examples)

Chapter 8

(Application Examples)

Your programming device user manual.

Address

I:1.0 I:1.1 I:1.2 I:1.3

•

I:1.7

W W W W

ord 0 ord 1 ord 2 ord 3

•

ord 7

SLC 500 Controller Data Files

Input Image

(8 words)

Channel 0 Data W

Channel 1 Data W Channel 2 Data W Channel 3 Data W Channel 0 Status W Channel 1 Status W Channel 2 Status W Channel 3 Status W

ord

ord ord ord

ord ord ord ord

Output Image

Address

I:1.0

000000000000000

ariable

Bit

Thermocouple Input Data)

Bit 0

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Quick Start for Experienced Users 2-7

9. Go through the system start-up proceedure. Reference

Apply power. Download your program to the SLC and put the controller into Run mode. In this example during a normal start up, the module status LED and channel status 0 LED turn on.

Chapter 7

(Module Diagnostics and Troubleshooting)

INPUT

CHANNEL STATUS

MODULE STATUS

THERMOCOUPLE/mV

012

Channel LEDs

Module Status LED

10. Check module operation. Reference

(Optional) Monitor the status of input channel 0 to determine its configuration setting and operational status. This is useful for troubleshooting when the blinking channel LED indicates that an error has occurred. If the Module Status LED is off, or if the Channel 0 LED is off or blinking, refer to chapter 7.

Chapter 5

(Channel Configuration, Data, and Status)

Chapter 6

(Ladder Programming Examples)

W W W

ord 0 ord 1 ord 2 ord 3

•

ord 7

SLC 500 Controller Data Files

Input Image

(8 words)

Channel 0 Data W Channel 1 Data W Channel 2 Data W

Channel 3 Data W

Channel 0 Status W

Channel 1 Status W Channel 2 Status W Channel 3 Status W

Output Image

ordW ord ord

ord

ord ord ord

Type

Open Circuit Error

Channel Status

Under Range Error

Configuration Error

Over Range Error

000010000000000

Bit

emperature Units

Filter Frequency

Address

Open Circuit

Data Format

Input

Bit 0

I:1.4

For this example, during normal operation only bit 11 is set.

Publication 1746-UM007C-EN-P - July 2004

Chapter 8

(Application Examples)

2-8 Quick Start for Experienced Users

Publication 1746-UM007C-EN-P - July 2004

Installation and Wiring

This chapter provides:

• Compliance to European Union Directives

• Electrostatic Discharge

• NT4 Power Requirements

• Module Location in Chassis

• Module Installation and Removal

• Terminal Wiring

• Thermocouple Calibration

Chapter

Compliance to European Union Directives

If this product has the CE mark it is approved for installation within the European Union and EEA regions. It has been designed and tested to meet the following directives.

EMC Directive

The Series B (or higher) 1746-NT4 is tested to meet Council Directive 89/336/EEC Electromagnetic Compatibility (EMC) and the following standards, in whole or in part, documented in a technical construction file:

• EN 50081-2

EMC - Generic Emission Standard, Part 2 - Industrial Environment

• EN 50082-2

EMC - Generic Immunity Standard, Part 2 - Industrial Environment

This product is intended for use in an industrial environment.

1 Publication 1746-UM007C-EN-P - July 2004

3-2 Installation and Wiring

Electrostatic Discharge

Electrostatic discharge can damage semiconductor devices inside this module if you touch backplane connector pins. Guard against electrostatic damage by observing the precautions listed next.

ATTENTION

•

Wear an approved wrist strap grounding device when handling

the module.

Touch a grounded object to rid yourself of electrostatic charge

•

before handling the module.

Handle the module from the front, away from the backplane

•

connector. Do not touch backplane connector pins.

Keep the module in its static-shield bag when not in use, or

•

during shipment.

Electrostatic discharge can degrade performance or cause permanent damage. Handle the module as stated below.

NT4 Power Requirements

The thermocouple module receives its power through the SLC500 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.

5V dc Amps 24V dc Amps

0.06 0.04

When you are using a modular system configuration, add the values shown in the table above to the requirements of all other modules in the SLC chassis to prevent overloading the chassis power supply.

When you are using a fixed system controller, refer to the important note about module compatibility in a 2-slot expansion chassis on page 3-3.

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Installation and Wiring 3-3

Module Location in Chassis

Place your thermocouple module in any slot of an SLC 500 modular, or modular expansion chassis, except for the extreme left slot (slot 0) in the first chassis. This slot is reserved for the processor or adapter.

Fixed Expansion Chassis Considerations

IMPORTANT

In the table:

• AN "x" indicates a valid combination.

• No symbol indicates an invalid combination.

• A "+" indicates an external power supply (refer to the SLC 500

4-Channel Analog I/O Modules User Manual, publication 1746-UM005 for more information).

The 2-slot, SLC 500 fixed I/O expansion chassis (1746-A2) will support only specific combinations of modules. If you are using the thermocouple module in a 2-slot expansion chassis with another SLC I/O or communication module, refer to the table starting below to determine whether the combination can be supported.

When using the table, be aware that there are certain conditions that affect the compatibility characteristics of the BASIC module (BAS) and the DH-485/RS-232C module (KE).

When you use the BAS module or the 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 24 VDC is calculated and recorded in the table for the modules identified as BASn (BAS networked) or KEn (KE networked). Make sure to refer to these modules if your application uses the BAS or KE module in this way.

1746- NT4 5V dc Amps 24V dc Amps

IA4 x 0.035 N/A IA8 x 0.050 N/A IA16 x 0.085 N/A IM4 x 0.035 N/A IM8 x 0.050 N/A

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3-4 Installation and Wiring

1746- NT4 5V dc Amps 24V dc Amps

IM16 x 0.085 N/A OA8 x 0.185 N/A OA16 x 0.370 N/A OAP12 x 0.370 N/A IB8 x 0.050 N/A IB16 x 0.085 N/A IV8 x 0.050 N/A IV16 x 0.085 N/A IG16 x 0.140 N/A OV8 x 0.135 N/A OV16 x 0.270 N/A OB8 x 0.135 N/A OBP8 x 0.135 N/A OG16 x 0.180 N/A OW4 x 0.045 0.045 OW8 x 0.085 0.090 OW16 0.170 0.180 IO4 x 0.030 0.025 IO8 x 0.060 0.045 IO12 x 0.090 0.070 NI4 x 0.025 0.085 NIO4I x 0.055 0.145 NIO4IV x 0.055 0.115 FIO4I x 0.055 0.150 FIO4V x 0.055 0.120 DCM x 0.360 N/A HS x 0.300 N/A OB16 x 0.28 N/A IN16 x 0.085 N/A BASn x 0.150 0.125 BAS x 0.150 0.040 OB32 0.452 N/A

Publication 1746-UM007C-EN-P - July 2004

OV32 0.452 N/A IV32 x 0.106 N/A IB32 x 0.106 N/A OX8 x 0.085 0.090 NO4I + 0.055 0.195

Installation and Wiring 3-5

1746- NT4 5V dc Amps 24V dc Amps

NO4V x 0.055 0.145 ITB16 x 0.085 N/A ITV16 x 0.085 N/A IC16 x 0.085 N/A KE x 0.150 0.040 KEn x 0.150 0.145 OBP16 x 0.250 N/A OVP16 x 0.250 N/A NT4 x 0.060 0.040 NR4 x 0.050 0.050 HSTP1 x 0.020 N/A

General Considerations

Module Installation and Removal

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.

When installing the module in a chassis, it is not necessary to remove the terminal block from the module. However, if the terminal block is removed, use the write-on label located on the side of the terminal block to identify the module location and type.

SLOT ____ RACK ____

• MODULE

_______________

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3-6 Installation and Wiring

Terminal Block Removal

ATTENTION

Never install, remove, or wire modules with power applied to the chassis or devices wired to the module.

To remove the terminal block:

1. Loosen the two terminal block release screws.

2. Grasp the terminal block at the top and bottom and pull

outward and down. When removing or installing the terminal block be careful not to damage the CJC sensors.

CJC Sensors

Terminal

Block Release

Screws

Publication 1746-UM007C-EN-P - July 2004

Module Installation Procedure

1. Align the circuit board of the thermocouple module with the

card guides located at the top and bottom of the chassis.

2. Slide the module into the chassis until both top and bottom

retaining clips are secured. Apply firm even pressure on the module to attach it to its backplane connector. Never force the module into the slot.

Installation and Wiring 3-7

3. Cover all unused slots with the Card Slot Filler, Catalog Number

1746-N2.

Top and Bottom Module Release(s)

Card Guide

Terminal Wiring

Module Removal Procedure

1. Press the releases at the top and bottom of the module and slide

the module out of the chassis slot.

2. Cover all unused slots with the Card Slot Filler, Catalog Number

1746-N2.

The thermocouple module contains a green, 18-position, removable terminal block. The terminal pin-out is shown on page 3-8.

ATTENTION

Disconnect Power to the SLC before attempting to install, remove, or wire the removable terminal wiring block.

To avoid cracking the removable terminal block, alternate the removal of the slotted terminal block release screws.

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3-8 Installation and Wiring

(Terminal Block Spare Part Catalog Number 1746-RT32)

Release Screw

Channel 0+

Channel 0

Channel 1+

Channel 1

Channel 2+

Channel 2

Channel 3+

Channel 3

Analog Common [see below]

CJC Assembly

Shield

CJC Assembly

Release Screw

CJC A+

CJC A

CJC B

CJC B+

Replacing a Series A thermocouple module with a Series B module requires that the bottom right terminal (which was SHIELD on Series A modules) no longer be connected to CHASSIS GROUND if it was previously. Use one of the other SHIELD terminals.

Wiring Considerations

ATTENTION

Follow the guidelines starting below when planning your system wiring.

• To limit noise, keep thermocouple and millivolt signal wires as

far away as possible from power and load lines.

Publication 1746-UM007C-EN-P - July 2004

Installation and Wiring 3-9

• To ensure proper operation and high immunity to electrical

noise, always use Belden

™ 8761 (shielded, twisted pair) or

equivalent wire for millivolt sensors or shielded, twisted pair thermocouple extension lead wire specified by the thermocouple manufacturer for the thermocouple type you are using. Using the incorrect thermocouple extension wire type or not following the correct polarity convention will cause invalid readings.

• Special considerations for using the analog common

(

ANALOG COM) terminal based on thermocouple type:

(See Appendix D for definitions of thermocouple types.)

– When using grounded thermocouple(s), jumper the

COM terminal to any single active grounded channel’s plus (+)

ANALOG

or minus (-) terminal.

– When using exposed thermocouple(s) that have the

thermocouple junction touching an electrically conductive material, jumper the

ANALOG COM terminal to any single active

exposed channel’s plus (+) or minus (-) terminal.

– When using ungrounded (shielded) or exposed

thermocouples that are not touching an electrically conductive material, do not use the

ANALOG COM terminal.

– When using a mix of grounded, ungrounded and exposed

thermocouples, jumper the

ANALOG COM terminal to any

single active grounded channel’s plus (+) or minus (-) terminal.

If millivolt inputs are used, the terminal should be handled as

–

discussed on page 1-7. The Series A 1746-NT4 does not have an

ANALOG COM

terminal and cannot be used with multiple grounded and/or exposed thermocouples that touch electrically conductive material. The Series A can be used with a single grounded and/or exposed thermocouple that touches electrically conductive material, or multiple grounded thermocouples that have the protective sheath made of an electrically non-conductive material such as ceramic.

• Ground the shield drain wire at one end only. The preferred

location is to the same point as the sensor ground reference.

– For grounded thermocouples or mV sensors, this is at the

sensor.

– For insulated/ungrounded thermocouples, this is at the

module.

– (Refer to IEEE Std. 518, Section 6.4.2.7 or contact your sensor

manufacturer for additional details.)

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3-10 Installation and Wiring

• If it is necessary to connect the shield at the module, each input

channel has a convenient shield connection screw terminal that provides a connection to chassis ground. All shields are internally connected, so any shield terminal can be used with channels 0-3. For maximum noise reduction, one shield terminal must be connected to earth ground potential, i.e. mounting bolt on 1746 chassis.

• Tighten terminal screws using a flat or cross-head screwdriver.

Each screw should be turned tight enough to immobilize the wire’s end. Excessive tightening can strip the terminal screw. The torque applied to each screw should not exceed 5 lb-in (0.565 Nm) for each terminal.

• The open thermocouple detection circuit injects approximately

12 nanoamperes into the thermocouple cable. A total lead resistance of 25 ohms (12.5 one-way) will produce 0.3 mV of error. To reduce error, use large gage wire with less resistance for long wire runs.

• Follow system grounding and wiring guidelines found in your

SLC 500 Modular Hardware Style User Manual (publication 1747-UM011).

Publication 1746-UM007C-EN-P - July 2004

Installation and Wiring 3-11

)

Wiring Input Devices to the NT4

After the thermocouple module is properly installed in the chassis, follow the wiring procedure below using the proper thermocouple extension cable, or Belden 8761 for non-thermocouple applications.

Signal Wire

Cable

Foil ShieldDrain Wire

(Twist together, shrink wrap,

and connect to earth ground.)

Signal Wire

(Cut foil shield and drain wire; then insulate at cable end.

Signal Wire

To wire your NT4 module:

1. At each end of the cable, strip some casing to expose the

individual wires.

2. Trim the signal wires to 2-inch lengths. Strip about 3/16 inch

(4.76 mm) of insulation away to expose the end of the wire.

3. At one end of the cable twist the drain wire and foil shield

together, bend them away from the cable, and apply shrink wrap. Then earth ground at the preferred location based on the type of sensor you are using (see Wiring Considerations).

4. At the other end of the cable, cut the drain wire and foil shield

back to the cable and apply shrink wrap.

5. Connect the signal wires to the NT4 terminal block and the

input.

6. Repeat steps 1 through 6 for each channel on the NT4 module.

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3-12 Installation and Wiring

Cold Junction Compensation (CJC)

ATTENTION

Do not remove or loosen the cold junction compensating thermistor assemblies located between the two upper and lower CJC terminals on the terminal block. Both thermistor assemblies are

critical to ensure accurate thermocouple input readings at each channel. The module will not

operate in the thermocouple mode if either assembly is removed.

To obtain accurate readings from each of the channels, the cold junction temperature (temperature at the module’s terminal junction between the thermocouple wire and the input channel) must be compensated for. Two cold junction compensating thermistors have been integrated in the removable terminal block; they must remain installed to retain accuracy.

In case of accidental removal of either or both of the thermistor assemblies, make sure to replace them by connecting each one across the CJC terminals located at the top and bottom left side of the terminal block. When connecting the thermistor assembly at the top of the terminal block (between terminals CJC A+ and CJC A-), the lug containing the thermistor (marked with red epoxy) should attach to the uppermost screw terminal (CJC A+). When connecting the thermistor assembly at the bottom of the terminal block (between terminals CJC B+ and CJC B-), the lug containing the thermistor should attach to the lowermost screw terminal (CJC B+).

Publication 1746-UM007C-EN-P - July 2004

CJC Assembly

Thermistor

(Always attach red lug to the CJC+ terminal.)

Bottom of Terminal Block

Installation and Wiring 3-13

Thermocouple Calibration

The thermocouple module is initially calibrated at the factory. The module also has an auto calibration function. Auto calibration compensates for offset and gain drift of the A/D converter caused by temperature change within the module. An internal, high precision, low drift voltage and system ground reference is used for this purpose. No external, user supplied device is required for autocalibration.

When an auto calibration cycle takes place, the module’s multiplexer is set to system ground potential and an A/D reading is taken. The A/D converter then sets its internal input to the modules precision voltage source, and another reading is taken. The A/D converter uses these numbers to compensate for “system” offset (zero) and gain (span) error.

Autocalibration of a channel occurs whenever a channel is enabled, or when a change is made to its input type or filter frequency. You can also command your module to perform an autocalibration cycle by disabling a channel, waiting for the status bit to change state (1 to 0) and then re-enabling that channel. Several channel cycles are required to perform an autocalibration, and it is important to remember that during autocalibration the module is not converting input data.

To maintain system accuracy we recommend that you periodically perform an autocalibration cycle, for example:

• whenever an event occurs that greatly changes the internal

temperature of the control cabinet, such as opening or closing its door

• at a convenient time when the system is not making product,

such as during a shift change

An autocalibration programming example is provided in chapter 6. Accuracy specifications with and without autocalibration are provided in Appendix A.

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3-14 Installation and Wiring

Publication 1746-UM007C-EN-P - July 2004

Chapter

Preliminary Operating Considerations

This chapter explains how the thermocouple module and the SLC processor communicate through the module’s input and output image. It lists the preliminary setup and operation required before the thermocouple module can function in a 1746 I/O system. Topics include:

• Module ID Code

• Module Addressing

• Channel Filter Frequency Selection

• Update Time

• Channel Turn-On, Turn-Off, and Reconfiguration Times

• Response to Slot Disabling

Module ID Code

The module identification code is a unique number encoded for each 1746 I/O module. The code defines for the processor the type of I/O or specialty module residing in a specific slot in the 1746 chassis.

The module ID code for the thermocouple module is shown below:

Catalog Number ID Code

1746-NT4 3510

No special I/O configuration information is required. The module ID code automatically assigns the correct number of input and output words.

1 Publication 1746-UM007C-EN-P - July 2004

4-2 Preliminary Operating Considerations

Module Addressing

SLC 5/0X Data Files

Slot e

Output Image

Slot e

Input Image

Output

Scan

Input Scan

The following memory map shows you how the output and input image tables are defined for the thermocouple module.

Bit

Thermocouple

Module

Image Table

Output Image

8 W

ords

Input Image

8 W

ords

(Class 1)

Output Image

Input Image

Channel 0 Configuration W Channel 1 Configuration W Channel 2 Configuration W Channel 3 Configuration W

Channel 0 Data W Channel 1 Data W Channel 2 Data W Channel 3 Data W Channel 0 Status W Channel 1 Status W Channel 2 Status W Channel 3 Status W

Bit 15

ords 4 7

(not defined)

ord ord ord ord

Bit 0

W W W W

W W

ord 0 ord 1 ord 2 ord 3

•

ord 7

ord 0 ord 1

ord 2

ord 3 ord 4

ord 5 ord 6

ord 7

Address

O:e.0 O:e.1

O:e.2 O:e.3

•

O:e.7

Address

I:e.0 I:e.1

I:e.2 I:e.3

I:e.4 I:e.5

I:e.6 I:e.7

Output Image-Configuration Words

The 8-word, thermocouple module output image (defined as the output from the CPU to the thermocouple module) contains information that you configure to define the way a specific channel on the thermocouple module will work. These words take the place of configuration DIP switches on the module. Although the thermocouple output image is eight words long, only output words 0-3 are used to define the operation of the module; output words 4-7 are not used. Each output word configures a single channel.

Example - If you want to configure channel 2 on the thermocouple module located in slot 4 in the chassis, your address would be O:4.2.

File Type

Element Delimiter

O : 4 . 2

Slot

Word

Word Delimiter

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Preliminary Operating Considerations 4-3

Chapter 5, Channel Configuration, Data, and Status, gives you detailed bit information about the data content of the configuration word.

Input Image-Data Words and Status Words

The 8-word, thermocouple module input image (defined as the input from the thermocouple module to the CPU) represents data words and status words.

Input words 0-3 (data words) hold the input data that represent the temperature value of thermocouple analog inputs for channels 0-3. This data word is valid only when the channel is enabled and there are no channel errors.

Input words 4-7 (status words) contain the status of channels 0-3 respectively. The status bits for a particular channel reflect the configuration settings that you have entered into the output image configuration word for that channel and provide information about the channel’s operational state. To receive valid status information the channel must be enabled, and the channel must have processed any configuration changes that may have been made to the configuration word.

Example - To obtain the status of channel 2 (input word 6) of the thermocouple module located in slot 4 in the SLC chassis, use address I:4.6.

File Type

Slot

Word

I : 4 . 6

Element Delimiter

Chapter 5, Channel Configuration, Data, and Status, gives you detailed bit information about the content of the data word and the status word.

Word Delimiter

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4-4 Preliminary Operating Considerations

Channel Filter Frequency Selection

The thermocouple module uses a digital filter that provides high frequency noise rejection for the input signals. The digital filter is programmable, allowing you to select from four filter frequencies for each channel. The digital filter provides the highest noise rejection at the selected filter frequency.

Selecting a low value (i.e. 10 Hz) for the channel filter frequency provides the best noise rejection for a channel, but it also increases the channel update time. Selecting a high value for the channel filter frequency provides lower noise rejection, but decreases the channel update time.

The following table shows the available filter frequencies, associated minimum normal mode rejection (NMR), cut-off frequency, and step response for each filter frequency.

Filter Frequency

10 Hz 100 dB 100 dB 2.62 Hz 300 msec 50 Hz 100 dB - 13.1 Hz 60 msec 60 Hz - 100 dB 15.72 Hz 50 msec

50Hz NMR 60Hz NMR Cut-Off

Frequency

Step Response

250 Hz - - 65.5 Hz 12 msec

Effective Resolution

The effective resolution for an input channel depends upon the filter frequency selected for that channel. Graphs that shows actual bit resolution for the thermocouple types at all filter frequencies are provided in Appendix A.

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Preliminary Operating Considerations 4-5

Channel Cut-Off Frequency

The channel filter frequency selection determines a channel’s cut-off frequency, also called the -3 dB frequency. The cut-off frequency is defined as the point on the input channel frequency response curve where frequency components of the input signal are passed with 3 dB of attenuation. All frequency components at or below the cut-off frequency are passed by the digital filter with less than 3 dB of attenuation. All frequency components above the cut-off frequency are increasingly attenuated, as show in the graphs starting below.

The cut-off frequency for each input channel is defined by its filter frequency selection. The table on the previous page lists the input channel cut-off frequency for each filter frequency. Choose a filter frequency so that your fastest changing signal is below that of the filter’s cut-off frequency. The cut-off frequency should not be confused with update time. The cut-off frequency relates how the digital filter attenuates frequency components of the input signal. The update time defines the rate at which an input channel is scanned and its channel data word updated.

60 Hz Filter Notch Frequency

Frequency Response

Amplitude

-3 dB

(in dB)

100

120

140

160

180

200

0 60 120 180 240 300

15.72 Hz

Frequency

Publication 1746-UM007C-EN-P - July 2004

4-6 Preliminary Operating Considerations

250 Hz Filter Notch Fre quency Frequency Response

Amplitude

-3 dB

(in dB)

100

120

140

160

180

200

0 250 500 750 1000 1250 1500

65.5 Hz

Channel Step Response

Frequency

The channel filter frequency determines the channel’s step response. The step response is time required for the analog input signal to reach 100% of its expected final value. This means that if an input signal changes faster than the channel step response, a portion of that signal will be attenuated by the channel filter. The table on page 4-4 shows the step response for each filter frequency.

Publication 1746-UM007C-EN-P - July 2004

Preliminary Operating Considerations 4-7

Update Time

The thermocouple module update time is defined as the time required for the module to sample and convert the input signals of all enabled input channels and make the resulting data values available to the SLC processor. It can be calculated by adding the the sum of all enabled channel sample times, plus a CJC update time.

The NT4 module sequentially samples the channels in a continuous loop.

Channel

0 Disabled

Enabled Enabled Enabled Enabled

Sample Channel 0

Update

CJC

Channel 1 Disabled Channel 2 Disabled Channel 3 Disabled

Sample Channel 1

Calculate Previous

Sample Channel 2

Calculate Previous Calculate Previous Calculate Previous

The following table shows the channel sampling times for each filter frequency. It also gives the CJC update time.

Sample Channel 3

Sample CJC Channels

CJC Update

Channel Sampling Time

Tim e

250 Hz Filter 60 Hz Filter 50 Hz Filter 10 Hz Filter

14 msec 12 msec 50 msec 60 msec 300 msec

The fastest module update time occurs when only one channel with a 250 Hz filter frequency is enabled.

Module update time = 12 ms + 14 ms = 26 ms

The slowest module update time occurs when four channels, each using a 10 Hz filter frequency (4 * 300 = 1200), are enabled.

Module update time = 1200 ms + 14 ms = 1.214 seconds

Publication 1746-UM007C-EN-P - July 2004

4-8 Preliminary Operating Considerations

Update Time Calculation Example

The following example shows how to calculate the module update time for the given configuration:

• channel 0 configured for 250 Hz filter frequency, enabled

• channel 1 configured for 250 Hz filter frequency, enabled

• channel 2 configured for 50 Hz filter frequency, enabled

• channel 3 disabled

Using the values from the table above, add the the sum of all enabled channel sample times, plus one CJC update time.

• channel 0 sampling time = 12 ms

• channel 1 sampling time = 12 ms

• channel 2 sampling time = 60 ms

• CJC update time = 14 ms

Module update time = 12 + 12 + 60 + 14 = 98 ms

Publication 1746-UM007C-EN-P - July 2004

Preliminary Operating Considerations 4-9

Channel Turn-On, Turn-Off, and Reconfiguration Times

The table below gives you the turn-on, turn-off, and reconfiguration times for enabling or disabling a channel.

Description Duration

Turn-On Time The time it takes to set the

status bit (transition from 0 to

1) in the status word, after setting the enable bit in the configuration word.

Turn-Off Time The time it takes to reset the

status bit (transition from 1 to

0) in the status word, after resetting the enable bit in the configuration word.

Reconfiguration Time

The time it takes to change a channel configuration if the device type, filter frequency, or configuration error bits are different from the current setting. The enable bit remains in a steady state of 1. (Changing temperature/mV units or data format does not require reconfiguration time.)

Requires up to one module update time plus one of the following:

• 250 Hz Filter = 82 ms

• 60 Hz Filter = 196 ms

• 50 Hz Filter = 226 ms

• 10 Hz Filter = 946 ms

Requires up to one module update time.

Requires up to one module update time plus one of the following:

• 250 Hz Filter = 82 ms

• 60 Hz Filter = 196 ms

• 50 Hz Filter = 226 ms

• 10 Hz Filter = 946 ms

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4-10 Preliminary Operating Considerations

Response to Slot Disabling

By writing to the status file in your modular SLC processor you can disable any chassis slot. Refer to your programming device‘s manual for the slot disable/enable procedure.

ATTENTION

Always understand the implications of disabling a thermocouple module before using the slot disable feature.

Input Response

When a thermocouple slot is disabled, the thermocouple module continues to update its input image table. However, the SLC processor does not read inputs from a module that is disabled. Therefore, when the processor disables the thermocouple module slot, the module inputs appearing in the processor image table remain in their last state, and the module’s updated image table is not read. When the processor re-enables the module slot, the current state of the module inputs are read by the processor during the subsequent scan.

Output Response

The SLC processor may change the thermocouple module output data (configuration) as it appears in the processor output image. However, this data is not transferred to the thermocouple module. The outputs are held in their last state. When the slot is re-enabled, the current data in the processor image is transferred to the thermocouple module.

Publication 1746-UM007C-EN-P - July 2004

Chapter

Channel Configuration, Data, and Status

This chapter examines the channel configuration word and the channel status word bit by bit, and explains how the module uses configuration data and generates status during operation. This chapter includes:

• Channel Configuration

• Channel Configuration Procedure

• Channel Data Word

• Channel Status Checking

• Status Conditions

Channel Configuration

Module Output Image (Configuration Word)

O:e.0

O:e.1

O:e.2

O:e.3

The channel configuration word is a part of the thermocouple module’s output image as shown below. Output words 0-3 correspond to channels 0-3 on the module. Output words 4-7 are not used.

After module installation each channel must be configured to establish the way the channel operates (e.g., thermocouple type J, reading in °C, etc.). You configure the channel by entering bit values into the configuration word using your programming software. Programming is discussed in chapter 6. Addressing is explained in chapter 4.

CH 0 Configuration Word

0123456789101112131415

CH 1 Configuration Word

0123456789101112131415

CH 2 Configuration Word

0123456789101112131415

CH 3 Configuration Word

0123456789101112131415

O:e.4 . . O:e.7

Not Used

The configuration word default setting is all zeros.

1 Publication 1746-UM007C-EN-P - July 2004

5-2 Channel Configuration, Data, and Status

Channel Configuration Procedure

The channel configuration word consists of bit fields, the settings of which determine how the channel will operate. This procedure looks at each bit field separately and helps you configure a channel for operation. Refer to the chart on page 5-4 and the bit field descriptions that follow for complete configuration information. Appendix B contains a configuration worksheet that can assist your channel configuration.

TIP

1. Determine the input device type (J, K, etc. thermocouple) (or

mV) for a channel and enter its respective 4-digit binary code in bit field 0-3 of the channel configuration word.

2. Select a data format for the data word value. Your selection

determines how the analog input value from the A/D converter will be expressed in the data word. Enter your 2-digit binary code in bit field 4-5 of the channel configuration word.

When using RSLogix 500 version 6.10 or higher, you can use the software’s I/O wizard to configure the NT4 channels. Refer to Appendix E for more information.

3. Determine the desired state for the channel data word if an open

circuit condition is detected for that channel. Enter the 2-digit binary code in bit field 6-7 of the channel configuration word.

4. If the channel is configured for thermocouple inputs or the CJC

sensor, determine if you want the channel data word to read in degrees Fahrenheit or degrees Celsius and enter a one or a zero in bit 8 of the configuration word. If the channel is configured for a mV analog sensor, enter a zero in bit 8.

5. Determine the desired input filter frequency for the channel and

enter the 2-digit binary code in bit field 9-10 of the channel configuration word. A lower filter frequency increases the channel update time, but also increases the noise rejection and channel resolution. A higher filter frequency decreases the channel update time, but also decreases the noise rejection and effective resolution.

6. Determine which channels are used in your program and enable

them. Place a one in bit 11 if the channel is to be enabled. Place a zero in bit 11 if the channel is to be disabled.

7. Ensure that bits 12-15 contain zeros.

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Channel Configuration, Data, and Status 5-3

8. Build the channel configuration word for every channel on each

thermocouple/mV module repeating the procedures given in steps 1-7.

9. Following the steps outlined in chapter 2, Quick Start for

Experienced Users, or in chapter 6, Ladder Programming Examples, enter this configuration data into your ladder program

and copy it to the thermocouple module.

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5-4 Channel Configuration, Data, and Status

Bit(s) Define To Select Make these bit settings in the Channel Configuration Word

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0-3 Input type Thermocouple Type J 0 0 0 0

Thermocouple Type K 0 0 0 1 Thermocouple Type T 0 0 1 0 Thermocouple Type E 0 0 1 1 Thermocouple Type R 0 1 0 0 Thermocouple Type S 0 1 0 1 Thermocouple Type B 0 1 1 0 Thermocouple Type N 0 1 1 1 50mV 1000 100mV 1001 Invalid 1010 Invalid 1011 Invalid 1100 Invalid 1101 Invalid 1110 CJC temperature 1 1 1 1

4 and 5 Data format

Engineering units x 1

Engineering units x 10

(2)

Scaled–for–PID 1 0 Proportional Counts 1 1

6 and 7 Open circuit Zero 0 0

Upscale 0 1 Downscale 1 0

Invalid 1 1

Tem p

(1)

9 and 10 Channel filter

frequency

11 Channel

enable

12-15 Unused Unused 0 0 0 0

Degrees C 0 Degrees F 1 10 Hz 0 0 50 Hz 0 1 60 Hz 1 0 250 Hz 1 1 Channel Disabled 0 Channel Enabled 1

(1) When millivolt input type is selected, the bit setting for temperature units is ignored.

(2) For engineering units x1, values are expressed in 0.1 degrees or 0.01 mV. For engineering units x10, values are expressed in 1.0 degrees or 0.1 mV.

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Channel Configuration, Data, and Status 5-5

Select Input Type (Bits 0-3)

The input type bit field lets you configure the channel for the type of input device you have connected to the module. Valid input devices are types J, K, T, E, R, S, B, and N thermocouple sensors and ±50 mV and ±100 mV analog input signals. The channel can also be configured to read the cold-junction temperature calculated for that specific channel. When the cold-junction compensation (CJC) temperature is selected, the channel ignores the physical input signal.

Select Data Format (Bits 4 and 5)

The data format bit field lets you define the expressed format for the channel data word contained in the module input image. The data types are engineering units, scaled-for-PID, and proportional counts.

The engineering units allow you to select from two resolutions, 1 or

10. For engineering units 1, values are expressed in 0.1 degrees or

0.01 mV. For engineering units

10, values are expressed in 1.0 degrees

or 0.1 mV. (Use the 10 setting to produce temperature readings in whole degrees Celsius or Fahrenheit.)

The scaled-for-PID value is the same for millivolt, thermocouple, and CJC input types. The input signal range is proportional to your selected input type and scaled into a 0-16,383 range, which is standard to the SLC PID algorithm.

The proportional counts are scaled to fit the defined temperature or voltage range. The input signal range is proportional to your selected input and scaled into a (-32,768 to 32,767) range.

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5-6 Channel Configuration, Data, and Status

Using Scaled-for-PID and Proportional Counts

The thermocouple module provides eight options for displaying input channel data. These are 0.1°F, 0.1°C, 1°F, 1°C, 0.01 mV, 0.1 mV, Scaled-for-PID, and Proportional Counts. The first six options represent real Engineering Units provided/displayed by the 1746-NT4, and do not require explanation. The Scaled-for-PID and Proportional Counts selections provide the highest NT4 display resolution, but also require you to manually convert the channel data to real Engineering Units.

The equations on page 5-7 show how to convert from Scaled-for-PID to Engineering Units, Engineering Units to Scaled-for-PID, Proportional Counts to Engineering Units, and Engineering Units to Proportional Counts. To perform the conversions, you must know the defined temperature or millivolt range for the channel’s input type. Refer to the Channel Data Word Format table on page 5-9. The lowest possible value for an input type is S

value is S

HIGH

, and the highest possible

LOW

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Scaling Examples

Scaled-for-PID to Engineering Units

Channel Configuration, Data, and Status 5-7

Equation: Engr Units Equivalent = S (Scaled-for-PID value displayed / 16384) ]

• Assume type J input type, scaled-for-PID display type, channel

data = 3421.

• Want to calculate °C equivalent.

• From Channel Data Word Format table, S

HIGH

Solution:

(3421 / 16384) ] = -7.46°C.

= 760°C.

Engr Units Equivalent = -210°C + [ (760°C - (-210°C) ) x

LOW

+ [ (S

- S

HIGH

= -210°C and

LOW

) x

Engineering Units to Scaled-for-PID

Equation: Scaled-for-PID Equivalent = 16384 x [ (Engineering Units desired - S

• Assume type J input type, scaled-for-PID display type, desired

channel temp. = 344°C.

• Want to calculate Scaled-for-PID equivalent.

• From Channel Data Word Format table, S

HIGH

LOW

= 760°C.

) / ( S

HIGH

- S

LOW

) ]

= -210°C and

LOW

Solution:

/ ( 760°C - (-210°C ) ) ] = 9357.

Scaled-for-PID Equivalent = 16384 x [ (344°C - (-210°C) )

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5-8 Channel Configuration, Data, and Status

Proportional Counts to Engineering Units

Equation: Engr Units Equivalent = S

LOW

+ { (S

HIGH

- S

LOW

)

x [ ( Proportional Counts value displayed + 32768) / 65536 ] }

• Assume type E input type, proportional counts display type,

channel data = 21567.

• Want to calculate °F equivalent.

• From Channel Data Word Format table, S

HIGH

Solution:

= 1832°F.

Engr Units Equivalent = -454°F + { [1832°F - (-454°F) ]

= -454°F and

LOW

x [ ( 21567 + 32768) / 65536 ] } = 1441.3°F

Engineering Units to Proportional Counts

Equation: Proportional Counts Equivalent = { 65536 x [ ( Engineering Units desired - S

LOW )

• Assume type E input type, proportional counts display type,

desired channel temp. = 1000°F.

• Want to calculate Proportional Counts equivalent.

• From Channel Data Word Format table, S

HIGH

= 1832°F.

/ ( S

HIGH

- S

LOW

) ] } - 32768

= -454°F and

LOW

Solution:

Proportional Counts Equivalent = { 65536 x [ ( 1000°F -

(-454°F) ) / (1832°F - (-454°F ) ) ] } - 32768 = 8916.

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Input Type Data Format

Channel Configuration, Data, and Status 5-9

1746-NT4 Thermocouple Module – Channel Data Word Format

Engineering Units x 10 Engineering Units x 1 Scaled–for–

PID

Proportional Counts

° Celsius ° Fahrenheit ° Celsius ° Fahrenheit

J -210 to 760 -346 to 1400 -2100 to 7600 -3460 to 14000 0 to 16383 -32768 to 32767 K -270 to 1370 -454 to 2498 -2700 to 13700 -4540 to 24980 0 to 16383 -32768 to 32767 T -270 to 400 -454 to 752 -2700 to 4000 -4540 to 7520 0 to 16383 -32768 to 32767 E -270 to 1000 -454 to 1832 -2700 to 10000 -4540 to 18320 0 to 16383 -32768 to 32767 R 0 to 1768 32 to 3214 0 to 17680 320 to 32140 0 to 16383 -32768 to 32767 S 0 to 1768 32 to 3214 0 to 17680 320 to 32140 0 to 16383 -32768 to 32767 B 300 to 1820 572 to 3308 3000 to 18200

5720 to 32767

(2)

0 to 16383 -32768 to 32767

N 0 to 1300 32 to 2372 0 to 13000 320 to 23720 0 to 16383 -32768 to 32767 ±50 mV

±100 mV

-500 to 500

(1)

-1000 to 1000

(1)

-500 to 500

-1000 to 1000

(1)

-5000 to 5000

(1)

-10000 to 10000

(1)

-5000 to 5000

(1)

-10000 to 10000

0 to 16383 -32768 to 32767

(1)

0 to 16383 -32768 to 32767

CJC Sensor 0 to 85 32 to 185 0 to 850 32 to 1850 0 to 16383 -32768 to 32767

(1) When millivolts are selected, the temperature setting is ignored. Analog input data is the same for either ° Celsius or ° Fahrenheit.

(2) Type B thermocouple cannot be represented in engineering units x 1 (° Fahrenheit) above 3276.7° Fahrenheit. Software treats it as an over range error.

1746-NT4 Thermocouple Module – Channel Data Word Resolution

Input

Data Format

Ty pe

Engineering Units x 10 Engineering Units x 1 Scaled–for–PID Proportional Counts

° Celsius ° Fahrenheit ° Celsius ° Fahrenheit ° Celsius ° Fahrenheit ° Celsius ° Fahrenheit

J 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.0592°C/step 0.1066°F/step 0.0148°C/step 0.0266°F/step K 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.1001°C/step 0.1802°F/step 0.0250°C/step 0.0450°F/step T 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.0409°C/step 0.0736°F/step 0.0102 °C/step 0.0184°F/step E 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.0775°C/step 0.1395°F/step 0.0194°C/step 0.0349°F/step R 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.1079°C/step 0.1942°F/step 0.0270°C/step 0.0486°F/step S 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.1079°C/step 0.1942°F/step 0.0270°C/step 0.0486°F/step B 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.0928°C/step 0.1670°F/step 0.0232°C/step 0.0417°F/step N 1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.0793°C/step 0.1428°F/step 0.0198°C/step 0.0357°F/step

±50 mV 0.1mV/step ±100 mV0.1mV/step

CJC Sensor

1°C/step 1°F/step 0.1°C/step 0.1°F/step 0.0052°C/step 0.0093°F/step 0.0013°C/step 0.0023°F/step

0.1mV/step

0.01mV/step

0.01mV/step 6.104 mV/step 6.104 mV/step 1.526 mV/step 1.526 mV/step

0.01mV/step 12.21 mV/step 12.21 mV/step 3.052 mV/step 3.052 mV/step

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5-10 Channel Configuration, Data, and Status

Select Open Circuit State (Bits 6 and 7)

The open-circuit bit field lets you define the state of the channel data word when an open-circuit condition is detected for that channel. This feature is active for thermocouple input types, millivolt input types, and CJC device input.

An open-circuit condition occurs when the thermocouple itself or its extension wire is physically separated or open. This can happen if the wire gets cut or disconnected from the terminal block.

If either of the two CJC devices (thermistors) are removed from the module wiring terminal, any input channel configured for either a thermocouple or CJC temperature input will be placed in an open circuit condition. An input channel configured for millivolt input is not affected.

If zero is selected, the channel data word is forced to 0 during an open-circuit condition.

Selecting upscale forces the channel data word value to its full scale value during an open-circuit condition. The full scale value is determined by the selected input type and data format.

Selecting downscale forces the channel data word value to its low scale value during an open-circuit condition. The low scale value is determined by the selected input type and data format.

IMPORTANT

You may receive up-ramping data values from the time the open circuit condition occurs until the condition is flagged. The NT4 requires 500 msec or one module update time, whichever is longer, to indicate the error. Depending on your program scan rate, ramping data may be written for several program scans after the open circuit occurs.

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Channel Configuration, Data, and Status 5-11

Select Temperature Units (Bit 8)

The temperature units bit lets you select temperature engineering units for thermocouple and CJC input types. Units are either degrees Celsius (°C) or degrees Fahrenheit (°F). This bit field is only active for thermocouple and CJC input types. It is ignored when millivolt inputs types are selected.

IMPORTANT

If you use engineering units (1 mode) and Fahrenheit temperature units (i.e. 0.1°F), the full scale temperature for thermocouple type B is not achievable with 15-bit numerical representation. An over range error will occur for that channel if it tries to represent the full scale value. The maximum representable temperature is 3276.7°F (instead of 3308°F).

Select Channel Filter Frequency (Bits 9 and 10)

The channel filter frequency bit field lets you select one of four filters available for a channel. The filter frequency affects the channel update time and noise rejection characteristics. A smaller filter frequency increases the channel update time, but also increases the noise rejection and channel resolution. A larger filter frequency decreases the noise rejection, but also decreases the channel update time and channel resolution.

• 250 Hz setting provides minimal noise filtering.

• 60 Hz setting provides 60 Hz AC line noise filtering.

• 50 Hz setting provides 50 Hz AC line noise filtering.

• 10 Hz setting provides both 50 Hz and 60 Hz AC line noise

filtering.

When a CJC input type is selected, this field is ignored.

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5-12 Channel Configuration, Data, and Status

Select Channel Enable (Bit 11)

You use the channel enable bit to enable a channel. The thermocouple module only scans those channels that are enabled. To optimize module operation and minimize throughput times, unused channels should be disabled by setting the channel enable bit to zero.

When set (1) the channel enable bit is used by the module to read the configuration word information you have selected. While the enable bit is set, modification of the configuration word may lengthen the module update time for one cycle. If any change is made to the configuration word, the change must be reflected in the status word before new data is valid. (Refer to Channel Status on page 5-13.)

While the channel enable bit is cleared (0), the channel data word and status word values are cleared. After the channel enable bit is set, the channel data word and status word remain cleared until the thermocouple module sets the channel status bit (bit 11) in the channel status word.

Channel Data Word

Module Input Image (Data Word)

I:e.0

I:e.1

I:e.2

I:e.3

Unused Bits (Bits 12-15)

Bits 12-15 are not defined. Ensure these bits are always cleared (0).

The actual thermocouple or millivolt input data values reside in I:e.0 through I:e.3 of the thermocouple module input image file. The values present will depend on the input type and data formats you have selected. When an input channel is disabled, its data word is reset (0).

Channel Data Word

CH 0

0123456789101112131415

Channel Data Word

CH 1

0123456789101112131415

CH 2 Channel Data Word

0123456789101112131415

Channel Data Word

CH 3

0123456789101112131415

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Channel Configuration, Data, and Status 5-13

Channel Status Checking

Module Input Image (Status Word)

I:e.4

I:e.5

I:e.6

I:e.7

The channel status word is a part of the thermocouple module’s input image. Input words 4-7 correspond to and contain the configuration status of thermocouple channels 0, 1, 2, and 3 respectively. You can use the data provided in the status word to determine if the input configuration data for any channel is valid per your configuration in O:e.0 through O:e.3.

For example, whenever a channel is disabled (O:e.x/11 = 0), its corresponding status word shows all zeros. This condition tells you that input data contained in the data word for that channel is not valid and should be ignored.

CH 0 Channel Status Word

0123456789101112131415

CH 1 Channel Status Word

0123456789101112131415

CH 2 Channel Status Word

0123456789101112131415

CH 3 Channel Status Word

0123456789101112131415

The channel status word can be analyzed bit by bit. In addition to providing information about an enabled or disabled channel, each bit’s status (0 or 1) tells you how the input data from the thermocouple or millivolt analog sensor connected to a specific channel will be translated for your application. The bit status also informs you of any error condition and can tell you what type error occurred.

A bit-by-bit examination of the status word is provided in the chart on the following page.

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5-14 Channel Configuration, Data, and Status

Bit(s) Define These bit settings Indicate this

1514131211109876543210

0–3 Input type 0 0 0 0 Thermocouple Type J

0 0 0 1 Thermocouple Type K

0 0 1 0 Thermocouple Type T

0 0 1 1 Thermocouple Type E

0 1 0 0 Thermocouple Type R

0 1 0 1 Thermocouple Type S

0 1 1 0 Thermocouple Type B

0 1 1 1 Thermocouple Type N

100050 mV

1 0 0 1 100 mV

1 0 1 0 Invalid

1 0 1 1 Invalid

1 1 0 0 Invalid

1 1 0 1 Invalid

1 1 1 0 Invalid

1 1 1 1 CJC temperature

4 and 5

Data type 1

6 and 7 Open circuit type 0 0 Zero

0 1 Upscale

10 Downscale

1 1 Invalid

8 Temperature units

9 and 10 Channel filter

(1)

type

frequency

0 0 10 Hz

0 1 50 Hz

0 Degrees C

1 Degrees F

1 0 60 Hz

1 1 250 Hz

11 Channel status 0 Channel Disabled

1 Channel Enabled

12 Open–circuit error 0 No error

1 Open circuit detected

13 Under–range error 0 No error

1 Under–range condition

14 Over–range error 0 No error

1 Over–range condition

15 Configuration error 0 No error

1 Configuration error

(1) When millivolt input type is selected, the bit setting for temperature units is ignored.

(2) For engineering units x1, values are expressed in 0.1 degrees or 0.01 mV. For engineering units x10, values are expressed in 1.0 degrees or 0.1 mV.

Engineering units x 1

Engineering units x 10

1 0 Scaled–for–PID

1 1 Proportional Counts

(2)

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Channel Configuration, Data, and Status 5-15

Status Conditions

IMPORTANT

If the channel for which you are seeking status is disabled (bit O:e.x/11 = 0), all bit fields are cleared. The status word for any disabled channel is always 0000 0000 0000 0000 regardless of any previous setting that may have been made to the configuration word.

Input Type Status (Bits 0-3)

The input type bit field indicates what type of input signal you have configured for the channel. This field reflects the input type defined in the channel configuration word.

Data Format Type Status (Bits 4 and 5)

The data format bit field indicates the data format you have defined for the channel. This field reflects the data type selected in bits 4 and 5 of the channel configuration word.

Open Circuit Type Status (Bits 6 and 7)

The open-circuit bit field indicates how you have defined the configuration word and, therefore, the response of the thermocouple module to an open-circuit condition. This feature is active for all input types, including CJC temperature input.

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5-16 Channel Configuration, Data, and Status

Temperature Units Type Status (Bit 8)

The temperature units field indicates the state of the temperature units bit in the configuration word (bit 8).

Channel Filter Frequency (Bits 9 and 10)

The channel filter frequency bit field reflects the filter frequency you selected in the configuration word.

Channel Status (Bit 11)

The channel status bit indicates the operational state of the channel. When the channel enable bit is set in the configuration word (bit 11), the thermocouple module configures the selected channel and takes a data sample for the channel data word before setting this bit in the status word.

Open-Circuit Error (Bit 12)

This bit is set (1) whenever a configured channel detects an open– circuit condition at its input. An open circuit at the CJC sensor will also flag this error if the channel input type is either thermocouple or CJC temperature.

Under-Range Error (Bit 13)

This bit is set (1) whenever a configured channel detects an under– range condition for the channel data. An under-range condition exists when the input value is below the specified lower limit of the particular sensor connected to that channel. An under-range temperature at the CJC sensor will also flag this error if the channel input type is either thermocouple or CJC temperature.

Publication 1746-UM007C-EN-P - July 2004

Channel Configuration, Data, and Status 5-17

Over-Range Error (Bit 14)

This bit is set (1) whenever a configured channel detects an over-range condition for the channel data. An over-range condition exists when the input value is above the specified upper limit of the particular sensor connected to that channel. An over-range temperature at the CJC sensor will also flag this error if the channel input type is either thermocouple or CJC temperature.

Configuration Error (Bit 15)

This bit is set (1) whenever a configured channel detects that the channel configuration word is not valid. All other status bits reflect the settings from the configuration word (even those settings that may be in error).

Publication 1746-UM007C-EN-P - July 2004

5-18 Channel Configuration, Data, and Status

Publication 1746-UM007C-EN-P - July 2004

Chapter

Ladder Programming Examples

Earlier chapters explained how the configuration word defines the way a channel operates. This chapter shows the programming required to enter the configuration word into the processor memory. It also provides you with segments of ladder logic specific to unique situations that might apply to your programming requirements. This chapter includes:

• Initial Programming

• Dynamic Programming

• Verifying Channel Configuration Changes

• Interfacing to the PID Instruction

• Monitoring Channel Status Bits

• Invoking Auto calibration

Initial Programming

To enter data into the channel configuration word (O:e.0 through O:e.3) when the channel is disabled (bit 11 = 0), follow the steps on page 6-2 for specific configuration details.

TIP

When using RSLogix 500 version 6.10 or higher, you can use the software’s I/O wizard to configure the NT4 channels.

1 Publication 1746-UM007C-EN-P - July 2004

6-2 Ladder Programming Examples

Example - Configure four channels of a thermocouple module residing in slot 3 of a 1746 chassis. Configure each channel with the same parameters.

0000

This example transfers configuration data and sets the channel enable bits of all four channels with a single File Copy instruction.

Procedure

001

910 8

16700 01450001

Bit Number

012315 14 13 12

Bit Setting

Configures Channel For:

•

Type K Thermocouple Input

•

Engineering Units 10

•

Zero If Open Circuit

•

Fahrenheit 10 Hz Filter Frequency

•

Channel Enable Bit

•

Not Used

•

1. Create integer file N10. Integer file N10 should contain four

elements (N10:0 through N10:3).

2. Enter the configuration parameters for all four thermocouple channels into a source integer data file N10. See Appendix B for a channel configuration worksheet.

3. Program a rung in your ladder logic to copy the contents of integer file N10 to the four consecutive output words of the thermocouple module beginning with O:3.0.

First Pass Bit

S:1

] [

On power up, bit S:1/15 is set for the first program scan, and integer file N10 is sent to the NT4 channel configuration words.

Initialize NT4

COP

COPY

FILE Source #N10:0 Dest #O:3.0 Length 4

Publication 1746-UM007C-EN-P - July 2004

Ladder Programming Examples 6-3

Dynamic Programming

Rung 2:1

The following example explains how to change data in the channel configuration word when the channel is currently enabled.

Example - Execute a dynamic configuration change to channel 2 of the thermocouple module located in slot 3 of a 1746 chassis. Change from monitoring an external type K thermocouple to monitoring the CJC sensors mounted on the terminal block. This gives a good indication of what the temperature is inside the control cabinet. Finally, set channel 2 back to type K thermocouple.

Program Listing

Set up all four channelsRung 2:0

S:1

] [

Set channel 2 to CJC

I:1.0

] [

[OSR]

COP

COPY

FILE Source #N10:0 Dest #O:3.0 Length 4

MOV MOVE Source N10:4

Dest O:3.2

Rung 2:2

Rung 2:3

address 15 data 0 address 15 data 0 N10:0 0000 1001 0001 0001 N10:3 0000 1001 0001 0001 N10:1 0000 1001 0001 0001 N10:4 0000 1001 0001 1111 N10:2 0000 1001 0001 0001

Set channel 2 back to type K

I:1.0

]/[

Data Table

[OSR]

MOV MOVE

END

Source N10:2

Dest O:3.2

IMPORTANT

While the module performs the configuration alteration, it does not monitor input device data change at any channel. Refer to page 4-9, Channel

Turn-On, Turn-Off, and Reconfiguration Times.

Publication 1746-UM007C-EN-P - July 2004

6-4 Ladder Programming Examples

Verifying Channel Configuration Changes

When executing a dynamic channel configuration change, there will always be a delay from the time the ladder program makes the change to the time the NT4 gives you a data word using that new configuration information. Therefore, it is very important to verify that a dynamic channel configuration change took effect in the NT4 module, particularly if the channel being dynamically configured is used for control. The following example explains how to verify that channel configuration changes have taken effect.

Example - Execute a dynamic configuration change to channel 2 of the thermocouple module located in slot 3 of a 1746 chassis, and set an internal “data valid” bit when the new configuration has taken effect.

Program Listing

Set up all four channels.Rung 2:0

COP

COPY

FILE Source #N10:0 Dest #O:3.0 Length 4

MOV MOVE Source N10:4

Dest O:3.2

Rung 2:1

S:1

] [

Set channel 2 to CJC.

I:1.0

] [

[OSR]

Rung 2:2

Rung 2:3

Rung 2:4

address 15 data 0 address 15 data 0 N10:0 0000 1001 0001 0001 N10:3 0000 1001 0001 0001 N10:1 0000 1001 0001 0001 N10:4 0000 1001 0001 1111 N10:2 0000 1001 0001 0001

Set channel 2 back to type K.

I:1.0

Check that the configuration written to channel 2 is being echoed back in channel 2's status word.

EQUAL Source

Source B

Data Table

]/[

EQU

[OSR]

I:3.6

O:3.2

END

MOV MOVE Source N10:2

Dest O:3.2

Data valid

( )

Publication 1746-UM007C-EN-P - July 2004

Ladder Programming Examples 6-5

Interfacing to the PID Instruction

Rung 2:1

Rung 2:2

Rung 2:3

The thermocouple module was designed to interface directly to the SLC 5/02 or later processor PID instruction without the need for an intermediate scale operation.

Example - Use NT4 channel data as the process variable in the PID instruction.

1. Select scaled-for-PID as the data type in the channel

configuration word.

2. Specify the thermocouple channel data word as the process

variable for the PID instruction.

Program Listing

First Pass Bit

S:1

] [

Channel 0

Status

I:3.4

] [

The Rate and Offset parameters should be set per your application. The Dest will typically be an analog output channel. Refer to your programming device's user manual or Analog I/O Modules User Manual for specific examples of the SCL instruction.

PID PID Control Process Variable Control Variable Control Block Length

SCALE Source N11:23

Rate

Offset

Dest

END

Initialize NT4

Channel 0Rung 2:0

MOV MOVE Source N10:0

Dest O:3.0

Block

SCL

N11:0

[/10000]

2081

I:3.0 N11:23 23

Data Table

address 15 data 0 address 15 data 0 N10:0 0000 1000 0010 0001

Publication 1746-UM007C-EN-P - July 2004

6-6 Ladder Programming Examples

Monitoring Channel Status Bits

This example shows how you could monitor the open circuit error bits of each channel and set an alarm in the processor if one of the thermocouples opens. An open circuit error can occur if the thermocouple breaks, one of the thermocouple wires gets cut or disconnected from the terminal block, or if the CJC thermistors are not installed or are damaged.

IMPORTANT

If a CJC thermistor is not installed or is damaged, all four alarms are set, and all four channel LEDs blink.

Program Listing

Rung 2:0

Rung 2:1 Channel 0

First Pass Bit

S:1

Status

I:3.4

] [

Channel 0 Open

I:3.4

] [

Initialize NT4

COP

COPY

FILE Source #N10:0 Dest #O:3.0 Length 4

Channel 0 Alarm

O:2.0

( )

Rung 2:2 Channel 1

Rung 2:3 Channel 2

Rung 2:4 Channel 3

Rung 2:5

address 15 data 0 address 15 data 0 N10:0 0000 1001 0001 0001 N10:3 0000 1001 0001 0001 N10:1 0000 1001 0001 0001 N10:2 0000 1001 0001 0001

Data Table

Status

I:3.5

] [ ] [

Status

I:3.6

Status

I:3.7

] [

Channel 1 Open

I:3.5

Channel 2 Open

I:3.6

Channel 3 Open

I:3.7

] [] [

] [

END

Channel 1 Alarm

O:2.0

Channel 2 Alarm

O:2.0

Channel 3 Alarm

O:2.0

( )

Publication 1746-UM007C-EN-P - July 2004

Ladder Programming Examples 6-7

Invoking Autocalibration

IMPORTANT

To maintain system accuracy we recommend that you periodically perform an autocalibration cycle, for example:

• whenever an event occurs that greatly changes the internal

temperature of the control cabinet, such as opening or closing its door

• at a convenient time when the system is not making product,

such as during a shift change

During autocalibration the module is not converting input data.

Several channel cycles are required to perform an autocalibration, and it is important to remember that during autocalibration the module is not converting input data.

Publication 1746-UM007C-EN-P - July 2004

6-8 Ladder Programming Examples

Example - Command the NT4 to perform an autocalibration of channel 0. The NT4 is in slot 3.

Program Listing

Rung 2:0 Channel 0 Enable

Condition for Autocalibration

I:1

] [

Channel 0 Status

I:3.4

]/[

IMPORTANT

[OSR]

Channel 0 Flag

] [

O:3.0

(U)

Channel 0 Flag

(L)

O:3.0

(L)

Channel 0 Flag

(U)

The NT4 responds to processor commands much more frequently than it updates its own LEDs. Therefore, it is normal to execute these two rungs and have the NT4 perform an autocalibraion of channel 0 without the channel 0 LED ever changing state.

Publication 1746-UM007C-EN-P - July 2004

Chapter

Module Diagnostics and Troubleshooting

This chapter describes troubleshooting using the channel status LEDs as well as the module status LED. It explains the types of conditions that might cause an error to be reported and gives suggestions on how to resolve the problem. This chapter includes:

• Module Operation vs. Channel Operation

• Power-up Diagnostics

• Channel Diagnostics

• LED Indicators

• Troubleshooting Flowchart

• Replacement Parts

• Contacting Rockwell Automation

Module Operation vs Channel Operation

Power-up Diagnostics

The thermocouple module performs operations at two levels:

• module level operations

• channel level operations

Module level operations include functions such as power–up configuration and communication with the SLC processor.

Channel level operations describe channel-related functions, such as data conversion and open-circuit detection.

Internal diagnostics are performed at both levels of operation and any error conditions detected are immediately indicated by the module’s LEDs.

At module powerup, a series of internal diagnostic tests is performed. These diagnostic tests must be successfully completed or a module error results and the module status LED remains off.

1 Publication 1746-UM007C-EN-P - July 2004

7-2 Module Diagnostics and Troubleshooting

Channel Diagnostics

When a channel is enabled (bit 11 = 1), a diagnostic check is performed to see that the channel has been properly configured. In addition the channel is tested for out-of-range and open-circuit faults on every scan. If the channel is configured for thermocouple input or CJC input, the CJC sensors are also checked for out-of-range and open circuits.

A failure of any channel diagnostic test causes the faulted channel status LED to blink. All channel faults are indicated in bits 12-15 of the channel’s status word. Channel faults are self-clearing, and the channel LED will stop blinking and resume steady illumination when the fault conditions are corrected.

IMPORTANT

If you clear (0) a channel enable bit (11) all channel status information is reset.

Publication 1746-UM007C-EN-P - July 2004

Module Diagnostics and Troubleshooting 7-3

LED Indicators

The thermocouple module has five LEDs. Four of these are channel status LEDs numbered to correspond to each of the thermocouple’s input channels, and one is a module status LED.

INPUT

CHANNEL STATUS

MODULE STATUS

THERMOCOUPLE/mV

If Module Status LED is:

And Channel Status LED is:

Indicated Condition: Corrective action:

On On Channel Enabled No action required.

Blinking Open Circuit Condition To determine the exact error, check the

Out-of-Range Condition

Channel Configuration Error

Off Power-Up No action required.

012

Channel LEDs

Module Status LED

error bits in the input image. Check the channel configuration word for valid data. Make sure that the input type is indicated correctly in bits 0-3, and that the open circuit selection state (bits 6 and 7) is valid. Refer to the troubleshooting flowchart on page 7-6 and chapter 5 for more information.

Channel Not Enabled No action required. For an example of how

to enable a channel refer to chapter 2, Quick Start for Experienced Users, or chapter 6, Programming Examples.

If Module

Indicated condition: Corrective action: Status LED is:

On Proper Operation No action required. Off Module Fault Cycle power. If condition persists, call your local

distributor or Rockwell Automation for assistance.

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7-4 Module Diagnostics and Troubleshooting

Channel Status LEDs (Green)

The channel LED is used to indicate channel status and related error information contained in the channel status word. This includes conditions such as:

• normal operation

• channel-related configuration errors

• open circuit errors

• out-of-range errors

All channel errors are recoverable errors and after corrective action, normal operation resumes.

Invalid Channel Configuration

Whenever a channel’s configuration word is improperly defined, the channel LED blinks and bit 15 of the channel status word is set. Configuration errors occur when the input type (bits 0-3 in the channel configuration word) is invalid, or when the open circuit state selection (bits 6 and 7) is invalid.

Open Circuit Detection

An open-circuit test is performed on all enabled channels. Whenever an open circuit condition occurs (see possible causes listed below), the channel LED blinks and bit 12 of the channel status word is set.

Possible causes of an open circuit include:

• The thermocouple may be broken.

• A thermocouple wire may be loose or cut.

• The thermocouple may not have been installed on the

configured channel.

• The CJC may be damaged.

Publication 1746-UM007C-EN-P - July 2004

If a damaged CJC termination is the cause of the detected open circuit condition, the status LED for each channel configured for thermocouple or CJC input blinks.

If an open-circuit is detected, the channel data word reflects input data as defined by the open-circuit bits (6 and 7) in the channel configuration word.

Module Diagnostics and Troubleshooting 7-5

Out-Of-Range Detection

Whenever the data received at the channel data word is out of the defined operating range, an over-range or under-range error is indicated and bit 13 (under-range) or 14 (over-range) of the channel status word is set. Refer to the temperature ranges provided in the table on page 5-9 for a review of the temperature range limitations for your input device.

Possible causes of an out-of-range condition include:

• The temperature is too hot or too cold for the thermocouple

being used.

• A type B thermocouple may be registering a °F value in

engineering units x 1 that cannot be expressed by the data bits. Refer to page 5-11 for more information.

• A CJC may be damaged or the temperature within the cabinet

containing the module may be outside the CJC range limits.

Module Status LED (Green)

The module status LED is used to indicate module-related diagnostic or operating errors. These non-recoverable errors may be detected at power-up or during module operation. Once in a module error state, the thermocouple module no longer communicates with the SLC processor. Channel states are disabled, and data words are cleared (0).

Failure of any diagnostic test results in a non-recoverable error and requires the assistance of your local distributor or Rockwell Automation.

Publication 1746-UM007C-EN-P - July 2004

7-6 Module Diagnostics and Troubleshooting

Troubleshooting Flowchart

Check LEDs

on module.

Module

Status LED of

Module fault

condition

Check to see

that module is

seated properly

in chassis.

Cycle power.

Module

Status LED on

Normal module

operation

End

Fault

condition

Are

faulted channel(s)

configured for mV or

thermocouple

input?

thermocouple

Is more than one

LED blinking?

Ye s

CJC fault

has occurred

Check

that wiring is secure at

both CJC assemblies and that

the temperature within the

enclosure is in the range limits

of the CJC sensor

. Retry.

Channel

Status LED(s)

blinking

Check channel

status word bits 12 15.

Channel

Status LED

off.

Channel is

not enabled.

Enable channel if

desired by setting

channel config.

word (bit 1

1 = 1).

Retry.

Channel

Status LED

on.

Channel enabled

and working

properly

End

Bit 15 set (1)

Configuration error configuration word bits 0-3

for valid input type

configuration as well as bits

6 and 7 for valid

configuration setting.

. Check

Retry.

Is problem corrected?

Contact your local

distributor or

Rockwell

Automation.

Yes

End

Publication 1746-UM007C-EN-P - July 2004

Yes

Contact your local

Is problem

corrected?

distributor or

Rockwell

Automation.

Bit 14

set (1)

Bit 13 set (1)

Bit 12

set (1)

Over-range condition

exists. The input signal is

greater than the high scale

limit for the channel or the

CJC connections. Correct

Under-range condition

exists. The input signal is

less than the low scale limit

for the channel or the CJC

connections. Correct and

An open-circuit condition is present. Check channel and CJC wiring for open or loose

connections. Retry.

and Retry

Retry.

Yes

Is problem corrected?

Contact your local

distributor or

Rockwell

Automation.

Module Diagnostics and Troubleshooting 7-7

Replacement Parts

Contacting Rockwell Automation

The NT4 module has the following replaceable parts:

Part Catalog Number

Replacement Terminal Block 1746-RT32 Replacement Terminal Cover 1746-R13 Series B 1746-NT4 Installation Instructions 1746-IN010

If you need to contact Rockwell Automation for assistance, please have the following information available when you call:

• a clear statement of the problem including a description of what

the system is actually doing. Note and record the LED states; also, note input and output image words for the NT4 module.

• a list of things you have already tried to remedy the problem

• processor type, 1747-NT4 series letter, and firmware (FRN)

number. See label on left side of processor.

• hardware types in the system including I/O modules and chassis

• fault code if the SLC processor is faulted

Publication 1746-UM007C-EN-P - July 2004

7-8 Module Diagnostics and Troubleshooting

Publication 1746-UM007C-EN-P - July 2004

Chapter

Application Examples

This chapter provides two application examples to help you use the thermocouple input module. They are defined as a:

• basic example

• supplementary example

The basic example builds on the configuration word programming provided in chapter 6 to set up one channel for operation. This setup is then used in a typical application to display temperature.

The supplementary example demonstrates how to perform a dynamic configuration of all four channels. The example sets up an application that allows you to manually select whether the displayed thermocouple input data for any channel is expressed in °C or °F.

Basic Example

SLC 5/02

Application Setup (Display a Temperature)

This example indicates the temperature of a bath on an LED display. The display requires BCD data, so the program must convert the temperature reading from the thermocouple module to BCD before sending it to the display. This application will display the temperature in °F.

Device Configuration

1746-OB16

1746-NT4

Thermocouple Type J

Bath

LED Display (DC sinking inputs, BCD format)

1 Publication 1746-UM007C-EN-P - July 2004

8-2 Application Examples

Channel Configuration

Configure the thermocouple channel with the following setup:

• type J thermocouple

• °F - display to whole degree

• zero data word in the event of an open circuit

• 10 Hz input filter to reject high frequency noise and give good

rejection of 60 Hz line noise

Channel Configuration Worksheet (With Settings Established for Channel 0)

12131415

0000

Bits:

0-3 Input Type Select 0000 = J

0001 = K 0010 = T 0011 = E

0010000

910 8

0100 = R 0101 = S 0110 = B 0111 = N

00 01450000

1000 = ±50 mV 1001 = ±100 mV 1111 = CJC temperature

0123

Bit Number

Channel

Channel 1

Channel 2

Channel 3

•

Input Type Select Data Format Select

•

Open Circuit Select

•

Temperature Units Select Filter Frequency Select

•

Channel Enable

•

Not Used

4 and 5 Data Format Select 00 = engineering units, x1 (0.1°/step,

0.01 mV/step)

10 = scaled-for-PID (0 to 16383) 11 = proportional counts (-32768 to +32767)

01 = engineering units, x10 (1°/step,

0.1 mV/step) 6 and 7 Open Circuit Select 00 = zero 01 = upscale 10 = downscale 8 Temperature Units

0 = degrees Celsius 1 = degrees Fahrenheit

Select 9 and 10 Filter Frequency Select 00 = 10 Hz 01 = 50 Hz 10 = 60 Hz 11 = 250 Hz 11 Channel Enable 0 = channel disabled 1 = channel enabled 12-15 Not Used 0000 = always make this setting

Publication 1746-UM007C-EN-P - July 2004

Program Listing

Application Examples 8-3

Rung 2.0

First Pass Bit

S:1

] [

Rung 2.1 Convert the channel 0 data word (degrees F) to BCD and write this to the LED display.

If channel 0 is ever disabled, a zero is written to the display..

Initialize Channel 0 of NT4

MOV MOVE Source N10:0

Dest O:3.0

TOD TO

BCD

Source I:3.0

Dest N7:0

MVM MASKED MOVE

Source N7:0 Mask 0FFF Dest O:2.0

Rung 2.2

END

The use of the masked move instruction with the 0FFF mask allows you to use outputs 12, 13, 14, and 15 for other output devices in your system. The 7-segment display uses outputs 0-11.

Data Table

address 15 data 0 address 15 data 0 N10:0 0000 1001 0001 0000

Publication 1746-UM007C-EN-P - July 2004

8-4 Application Examples

Supplementary Example

1746-NT4

SLC 5/02

Application Setup (Four Channels °C - °F)

This example shows how to display the temperature of several different thermocouples at one annunciator panel. A selector switch (I:2/0) allows the operator to choose between displaying data in °C and °F. A second selector switch (I:2/1) allows the operator to switch one of the displays between the ambient temperature near the bath and the temperature inside of the control cabinet that houses the SLC

500. Each of the displays is a 4-digit, 7-segment LED display with the last digit representing tenths of a degree. The displays have DC-sinking inputs and use a BCD data format.

Device Configuration

1746-IB8

(5).1746-OB16

Ambient Temperature Thermocouple Type T

Display Panel

Cabinet

Ambient

BathAmbient

. .

Selector Switches (I:2/1) and (I:2/0)

. .

Chilled H2OSteam

Bath Thermocouple Type J

Chilled H2O Pipe

Type J

Chilled Thermocouple

Type K

Steam Thermocouple

Steam Pipe

Publication 1746-UM007C-EN-P - July 2004

Application Examples 8-5

Channel Configuration

Configuration setup for ambient thermocouple:

• channel 0

• type T thermocouple

• display temperature to tenths of a degree

• zero data word in the event of an open circuit

• 60 Hz input filter to provide 60 Hz line noise rejection

Configuration setup for bath thermocouple:

• channel 1

• type J thermocouple

• display temperature to tenths of a degree

• zero data word in the event of an open circuit

• 60 Hz input filter to provide 60 Hz line noise rejection

Configuration setup for steam thermocouple:

• channel 2

• type K thermocouple

• display temperature to tenths of a degree

• zero data word in the event of an open circuit

• 60 Hz input filter to provide 60 Hz line noise rejection

Configuration setup for chilled H2O thermocouple:

• channel 3

• type J thermocouple

• display temperature to tenths of a degree

• zero data word in the event of an open circuit

• 60 Hz input filter to provide 60 Hz line noise rejection

Configuration setup for cabinet temperature:

• channel 0

• CJC temperature

• display temperature to tenths of a degree

• zero data word in the event of an open circuit

• 60 Hz input filter to provide 60 Hz line noise rejection

Publication 1746-UM007C-EN-P - July 2004

8-6 Application Examples

Channel Configuration Worksheet (With Settings Established)

12131415

0000

Bits:

0-3 Input Type Select 0000 = J

0001 = K 0010 = T 0011 = E

1010000

101

910 8

x6700 00450010

0100 = R 0101 = S 0110 = B

0000

0001

0000

1000 = ±50 mV 1001 = ±100 mV 1111 = CJC temperature

0111 = N

0123

Bit Number

Channel 0

Channel 1

Channel 2

Channel 3

•

Input Type Select

•

Data Format Select Open Circuit Select

•

Temperature Units Select

•

Filter Frequency Select

•

Channel Enable

•

Not Used

(Ambient)

(Bath)

(Steam)

(Chilled H2O)

4 and 5 Data Format Select 00 = engineering units, x1 (0.1°/step,

0.01 mV/step)

10 = scaled-for-PID (0 to 16383) 11 = proportional counts (-32768 to +32767)

01 = engineering units, x10 (1°/step,

0.1 mV/step) 6 and 7 Open Circuit Select 00 = zero 01 = upscale 10 = downscale 8 Temperature Units

0 = degrees Celsius 1 = degrees Fahrenheit

Select 9 and 10 Filter Frequency Select 00 = 10 Hz 01 = 50 Hz 10 = 60 Hz 11 = 250 Hz 11 Channel Enable 0 = channel disabled 1 = channel enabled 12-15 Not Used 0000 = always make this setting

Publication 1746-UM007C-EN-P - July 2004

Application Examples 8-7

Program Setup and Operation Summary

1. Set up two configuration words in memory for each channel,

one for °C and the other for °F. In addition, set up two configuration words to monitor the thermocouple’s CJC temperature. Monitoring the CJC temperature gives a good indication of the temperature inside of the control cabinet the SLC is mounted in. The table below shows the configuration word allocation summary.

Channel Configuration Word Allocation

°F °C

1 N10:0 N10:4 2 N10:1 N10:5 3 N10:2 N10:6 4 N10:3 N10:7 CJC N10:8 N10:9

2. When the positions of the degrees selector switch or

ambient/cabinet selector switch change, write the appropriate channel configurations to the NT4 module. Note that the use of the OSR instruction (one-shot rising) makes these configuration changes edge-triggered, i.e. the NT4 is reconfigured only when a selector switch changes position.

Cabinet

Selector Switches:

Ambient

3. Monitor the channel 0 status word to determine which

temperature is being displayed (ambient or cabinet) and energize the appropriate pilot light.

4. Convert the individual thermocouple data words to BCD and

send the data to the respective LED displays.

Program Listing

The first six rungs of the program starting on the next page send the correct channel setup information to the NT4 module based on the position of the two selector switches.

Publication 1746-UM007C-EN-P - July 2004

8-8 Application Examples

Rung 2.0

If the degrees selector switch is turned to the Fahrenheit position, set up all four channels to read in degrees Fahrenheit. The default for channel 0 is to read the ambient temperature thermocouple.

Degrees Selector Switch Fahrenheit

I:2.0

] [

OSR

Configure NT4 Channels

COP

COPY

FILE Source #N10:0 Dest #O:1.0 Length 4

Rung 2.1 If the ambient/cabinet selector switch is turned to the ambient position and the degrees selector

switch is in the Farenheit position, configure channel 0 to read the ambient temperature thermocouple in degrees Fahrenheit.

Degrees Selector Switch Fahrenheit

I:2.0

] [

Ambient/Cabinet Selector Switch Ambient

I:2.0

] [

OSR

Configure NT4 Channels

MOV

MOVE

Source N10:0

Dest O:1.0

Rung 2.2

If the ambient/cabinet selector switch is turned to the cabinet position and the degrees selector switch is in the Farenheit position, configure channel 0 to read the CJC sensor on the NT4 module in degrees Fahrenheit.

Degrees Selector Switch Fahrenheit

I:2.0

] [

Rung 2.3

If the degrees selector switch is turned to the Celsius position, set up all four channels to read in degrees Celsius. The default for channel 0 is to read the ambient temperature thermocouple.

Ambient/Cabinet Selector Switch Ambient

I:2.0

]/[

OSR

Configure NT4 Channels

MOV

MOVE

Source N10:8

Dest O:1.0

Degrees Selector Switch Celsius

I:2.0

Publication 1746-UM007C-EN-P - July 2004

]/[

OSR

Configure NT4 Channels

COP

COPY

FILE

Source #N10:4 Dest #O:1.0 Length 4

Application Examples 8-9

Rung 2.4 If the ambient/cabinet selector switch is turned to the ambient position and the degrees selector

switch is in the Celsius position, configure channel 0 to read the ambient temperature thermocouple in degrees Celsius.

Degrees Selector Switch Celsius

I:2.0

]/[

Ambient/Cabinet Selector Switch Ambient

I:2.0

] [

OSR

Configure NT4 Channels

MOV

MOVE

Source N10:4

Dest O:1.0

Rung 2.5

If the ambient/cabinet selector switch is turned to the cabinet position and the degrees selector switch is in the Celsius position, configure channel 0 to read the CJC sensor on the NT4 module in degrees Celsius.

Degrees Selector Switch Celsius

I:2.0

] [

Rung 2.6 If channel 0 is set up for reading the ambient thermocouple, energize the ambient pilot light on

the annunciator panel.

MEQ MASKED Source I:1.4

Mask FEFF

Compare N1 0:4

Ambient/Cabinet Selector Switch Cabinet

I:2.0

EQUAL

]/[

OSR

Configure NT4 Channels

MOV

MOVE

Source N10:9

Dest O:1.0

Ambient Light

O:7.0

( )

Rung 2.7

If channel 0 is set up for reading the CJC sensor on the NT4 module, energize the cabinet pilot light on the annunciator panel.

Cabinet Light

MEQ MASKED

EQUAL

Source I:1.4

O:7.0

( )

Mask FEFF

Compare N10:9

Publication 1746-UM007C-EN-P - July 2004

8-10 Application Examples

Rung 2.8 Convert the NT4 data words to BCD format and send to the LED displays.

Rung 2.9

Rung 2.10

Rung 2.11

Write NT4

Ambient or Cabinet

Temperature to Display

TOD

BCD

Source I:1.0

Dest O:3.0

Write NT4

Bath

Temperature to Display

TOD

BCD

Source I:1.1

Dest O:4.0

Write NT4

Steam

Temperature to Display

TOD

BCD

Source I:1.2

Dest O:5.0

Write NT4 Chilled

Temperature to Display

TOD

BCD

Source I:1.3

address 15 data 0 address 15 data 0 N10:0 0000 1101 0000 0010 N10:5 0000 1100 0000 0000 N10:1 0000 1101 0000 0000 N10:6 0000 1100 0000 0001 N10:2 0000 1101 0000 0001 N10:7 0000 1100 0000 0000 N10:3 0000 1101 0000 0000 N10:8 0000 1101 0000 1111 N10:4 0000 1100 0000 0010 N10:9 0000 1100 0000 1111

Publication 1746-UM007C-EN-P - July 2004

Dest O:6.0

Rung 2.12

END

Data Table

Electrical Specifications

Appendix

Specifications

This appendix lists the specifications and input resolution curves for the 1746-NT4 4-Channel Thermocouple/mV Input Module.

Specification Value

Backplane Current Consumption

Backplane Power Consumption

Number of Channels 4 (backplane isolated) I/O Chassis Location Any I/O module slot except slot 0 A/D Conversion Method Sigma-Delta Modulation Input Filtering Low pass digital filter with programmable notch (filter)

Normal Mode Rejection (between [+] input and [-] input)

Common Mode Rejection (between inputs and chassis ground)

Input Filter Cut-Off Frequencies

Calibration Module autocalibrates at power-up and whenever a channel

Isolation 500V dc continuous between inputs and chassis ground, and

60 mA at 5V dc 40 mA at 24V dc

0.8W maximum (0.3W @ 5V dc, 0.5W @ 24V dc)

frequencies Greater than 100 dB at 50 Hz (10 Hz, 50 Hz filter frequencies)

Greater than 100 dB at 60 Hz (10 Hz, 60 Hz filter frequencies)

Greater than 150 dB at 50 Hz (10 Hz, 50 Hz filter frequencies) Greater than 150 dB at 60 Hz (10 Hz, 60 Hz filter frequencies)

2.62 Hz at 10 Hz filter frequency

13.1 Hz at 50 Hz filter frequency

15.72 Hz at 60 Hz filter frequency

65.5 Hz at 250 Hz filter frequency

is enabled.

between inputs and backplane.

Maximum Channel-to-Channel Common-Mode Separation

1 Publication 1746-UM007C-EN-P - July 2004

Series B or later: 2V maximum between any two channels Series A: 0V separation

A-2 Specifications

Physical Specifications

Specification Value

LED Indicators 5, green status indicators, one for each of 4 channels

and one for module status Module ID Code 3510 Recommended Cable: For Thermocouple inputs Appropriate shielded twisted pair thermocouple

extension wire

(1)

For mV inputs Belden #8761 or equivalent Maximum Wire Size Two 14 AWG wires per terminal

Environmental Specifications

Maximum Cable Impedance 25

ohms maximum loop impedance, for <1LSB error

Terminal Block Removable, Allen-Bradley spare part Catalog Number

1746-RT32

(1) Refer to the thermocouple manufacturer for the correct extension wire.

Specification Value

Operating Temperature

(1)

0°C to 60°C (32°F to 140°F)

Storage Temperature -40°C to +85°C (-40°F to +185°F) Relative Humidity 5% to 95% (without condensation) Certification

C-UL Listed Industrial Control Equipment for use in Class 1, Div 2 Hazardous Locations

Marked for all applicable directives

CSA approved

Publication 1746-UM007C-EN-P - July 2004

(1) When the NT4 module detects 0°C (32°F) [(+/- 3°C) +/- 5.4°F] at the CJC, it will detect an out-of-range condition

and set values to downscale -270°C (-454°F). It is recommended that ambient temperature surrounding the SLC 500 system be maintained above 3°C (37.4°F) in order for the NT4 module to measure temperature correctly without detecting an out-of-range condition.

Input Specifications

Specification Value

Type of Input (Selectable) Thermocouple Type J -210°C to 760°C (-346°F to 1400°F)

Thermocouple Linearization IPTS-68 standard, NBS MN-125, NBS MN-161 Cold Junction Compensation Accuracy ±1.5°C, 0°C to 85°C (32°F to 185°F) Input Impedance Greater than 10MW Temperature Scale (Selectable) °C or °F and 0.1°C or 0.1°F DC Millivolt Scale (Selectable) 0.1 mV or 0.01 mV

Specifications A-3

Thermocouple Type K -270°C to 1370°C (-454°F to 2498°F) Thermocouple Type T -270°C to 400°C (-454°F to 752°F) Thermocouple Type E -270°C to 1000°C (-454°F to 1832°F) Thermocouple Type R 0°C to 1768°C (32°F to 3214°F) Thermocouple Type S 0°C to 1768°C (32°F to 3214°F) Thermocouple Type B 300°C to 1820°C (572°F to 3308°F) Thermocouple Type N (14 AWG) 0°C to 1300°C (32°F to 2372°F)

Millivolt (-50 mV dc to +50 mV dc) Millivolt (-100 mV dc to +100 mV dc)

Open Circuit Detection Leakage Current

Open Circuit Detection Method Upscale Time to Detect Open Circuit 500 msec or 1 module update time, whichever is greater Input Step Response See Channel Step Response, page 4–6. Input Resolution See Input Resolution Graphs on following pages. The graphs show the

Display Resolution See Channel Data Word, page 5-12. Overall Module Accuracy

@ 25°C (77°F) Overall Module Accuracy

(0°C to 60°C, 32°F to 140°F) Overall Module Drift See 1746-NT4 Module Accuracy, page A-4 Module Update Time See Update Time, page 4-7 Channel Turn-On Time,

Reconfiguration Time

12 nA maximum

smallest measurable unit based on the combined hardware and software tolerances.

See 1746-NT4 Module Accuracy, page A-4

Requires up to one module update time plus one of the following:

50 Hz Filter= 82 milliseconds 60 Hz Filter= 196 milliseconds 50 Hz Filter= 226 milliseconds 10 Hz Filter= 946 milliseconds

Channel Turn-Off Time Requires up to one module update time (refer to page 4–7)

Publication 1746-UM007C-EN-P - July 2004

A-4 Specifications

1746-NT4 Module Accuracy

Input Resolution per

Input Type

With Autocalibration Maximum Error

@ 25°C

(1)

Maximum Error @ 77°F

Without Autocalibration Temperature Drift

(0°C-60°C)

J ±1.06°C ±1.91°F ±0.0193°C/°C, °F/°F K ±1.72°C ±3.10°F ±0.0328°C/°C, °F/°F T ±1.43°C ±2.57°F ±0.0202°C/°C, °F/°F E ±0.72°C ±1.3°F ±0.0190°C/°C, °F/°F S ±3.61°C ±6.5°F ±0.0530°C/°C, °F/°F R ±3.59°C ±6.46°F ±0.0530°C/°C, °F/°F B ±3.12°C ±5.62°F ±0.0457°C/°C, °F/°F N ±1.39°C ±2.5°F ±0.0260°C/°C, °F/°F ±50 mV ±50 mV ±50 mV ±1.0 mV/°C, ±1.8 mV/°F ±100 mV ±50 mV ±50 mV ±1.5 mV/°C, ±2.7 mV/°F

(1) Assumes the module terminal block temperature is stable.

(1)

Thermocouple Type at Each Filter Frequency

Resolution

250 Hz 50/60 Hz 10 Hz

12.80

23.04

9.60

17.28

6.40

11.52

3.20

5.76

1.60

2.88

1.20

2.16

0.80

1.44

0.40

0.72

1.44

1.08

0.72

0.36

Type

0.8

0.6

0.4

0.2

0.0

300 150 0 150 300 450 600 750 900 1050 1200

508 238 32 302 572 842 111 2 1382 1652 1922 2192

E Thermocouple

Temperature

(C)

(F)

Publication 1746-UM007C-EN-P - July 2004

Rockwell Automation 1746-NT4 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Important User Information

Summary of Changes

Table of Contents

Preface

Overview

General Description

System Overview

Input Circuit Block Diagram

Quick Start for Experienced Users

Required Tools and Equipment

Installation Procedures

Installation and Wiring

Compliance to European Union Directives

Electrostatic Discharge

NT4 Power Requirements

Module Location in Chassis

Module Installation and Removal

Terminal Wiring

Thermocouple Calibration

Preliminary Operating Considerations

Module ID Code

Module Addressing

Channel Filter Frequency Selection

Update Time

Channel Turn-On, Turn-Off, and Reconfiguration Times

Response to Slot Disabling

Channel Configuration, Data, and Status

Channel Configuration

Channel Configuration Procedure

Scaled-for-PID to Engineering Units

Engineering Units to Scaled-for-PID

Proportional Counts to Engineering Units

Engineering Units to Proportional Counts

Channel Data Word

Channel Status Checking

Status Conditions

Ladder Programming Examples

Initial Programming

Dynamic Programming

Verifying Channel Configuration Changes

Interfacing to the PID Instruction

Monitoring Channel Status Bits

Invoking Autocalibration

Module Diagnostics and Troubleshooting

Module Operation vs Channel Operation

Power-up Diagnostics

Channel Diagnostics

LED Indicators

Troubleshooting Flowchart

Replacement Parts

Contacting Rockwell Automation

Application Examples

Basic Example

Channel Configuration Worksheet (With Settings Established for Channel 0)

Supplementary Example

Channel Configuration Worksheet (With Settings Established)

Electrical Specifications

Specifications

Physical Specifications

Environmental Specifications

Input Specifications