Rockwell Automation 1790D-NOV2, 1790DTNOV2 User Manual

CompactBlock LDX Analog Modules

1790D-N4CO/TN4CO,

-N4VO/TN4VO, -NOC2/TNOC2,

-NOV2/TNOV2, 1790P-TN4CO,

-TNOC2

User Manual

Important User Information

Because of the variety of uses for the products described in this publication, those responsible for the application and use of these products must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes and standards. In no event will Allen-Bradley be responsible or liable for indirect or consequential damage resulting from the use or application of these products.

Any illustrations, charts, sample programs, and layout examples shown in this publication are intended solely for purposes of example. Since there are many variables and requirements associated with any particular installation, Allen-Bradley does not assume responsibility or liability (to include intellectual property liability) for actual use based upon the examples shown in this publication.

Allen-Bradley publication SGI-1.1, Safety Guidelines for the

Application, Installation and Maintenance of Solid-State Control

(available from your local Allen-Bradley office), describes some important differences between solid-state equipment and electromechanical devices that should be taken into consideration when applying products such as those described in this publication.

Reproduction of the contents of this copyrighted publication, in whole or part, without written permission of Rockwell Automation, is prohibited.

Throughout this publication, notes may be used to make you aware of safety considerations. The following annotations and their accompanying statements help you to identify a potential hazard, avoid a potential hazard, and recognize the consequences of a potential hazard:

WARNING

Identifies information about practices or circumstances that can cause an explosion in a hazardous environment, which may lead to personal injury or death, property damage, or economic loss.

ATTENTION

Identifies information about practices or circumstances that can lead to personal injury or death, property damage, or economic loss.

IMPORTANT

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

Rockwell Automation Support

Before you contact Rockwell Automation for technical assistance, we suggest you please review the troubleshooting information contained in this publication first.

If the problem persists, call your local distributor or contact Rockwell Automation in one of the following ways:

Phone United

States/Canada

Outside United States/Canada

Internet

⇒

1.440.646.5800

You can access the phone number for your country via the Internet:

1. Go to http://www.ab.com

2. Click on Product Support (http://support.automation.rockwell.com)

3. Under Support Centers, click on Contact

Information

1. Go to http://www.ab.com

2. Click on Product Support (http://support.automation.rockwell.com)

Your Questions or Comments on this Manual

If you find a problem with this manual, please notify us of it on the enclosed How Are We Doing form.

Preface

Read this preface to familiarize yourself with the rest of the manual. This preface covers the following topics:

• who should use this manual

• how to use this manual

• related publications

• conventions used in this manual

• Rockwell Automation support

Who Should Use This Manual

How to Use This Manual

Use this manual if you are responsible for designing, installing, programming, or troubleshooting control systems that use Allen-Bradley CompactBlock LDX modules.

As much as possible, we organized this manual to explain, in a task-by-task manner, how to install, configure, program, operate and troubleshoot a control system using the 1790D analog I/O modules.

Manual Contents

If you want... See

An overview of the analog input and output modules Chapter 1

Installation and wiring guidelines Chapter 2

Input module addressing, configuration and status information Chapter 3

Output module addressing, configuration and status information Chapter 4

Information on module diagnostics and troubleshooting Chapter 5

Specifications for the input and output modules Appendix A

PROFIBUS information Appendix B

Definitions of terms used in this manual Glossary

1 Publication 1790-UM001A-EN-P - March 2002

Preface 2

Conventions Used in This Manual

Publication 1790-UM001A-EN-P - March 2002

The following conventions are used throughout this manual:

• Bulleted lists (like this one) provide information not procedural

steps.

• Numbered lists provide sequential steps or hierarchical

information.

• Italic type is used for emphasis.

• Text in this font indicates words or phrases you should type.

Overview

Installation and Wiring

Chapter 1

How to Use Analog I/O . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Hardware Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

General Diagnostic Features . . . . . . . . . . . . . . . . . . . . . 1-4

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

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

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

Chapter 2

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Module Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Prevent Electrostatic Discharge . . . . . . . . . . . . . . . . . . . 2-2

Environmnet and Enclosure . . . . . . . . . . . . . . . . . . . . . 2-2

Remove Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Reducing Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Protecting the Circuit Board from Contamination. . . . . . 2-3

Installing CompactBlock LDX I/O . . . . . . . . . . . . . . . . . . . 2-4

Set the Node Address on the Base Block . . . . . . . . . . . 2-4

Mount the Base Block . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Mount the Optional Expansion Blocks . . . . . . . . . . . . . 2-6

Connect the DeviceNet Cable . . . . . . . . . . . . . . . . . . . . 2-7

I/O System Wiring Guidelines . . . . . . . . . . . . . . . . . . . . . . 2-8

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Input Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Output Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Effect of Transducer/Sensor and Cable Length

Impedance on Voltage Input Accuracy . . . . . . . . . . . . . 2-9

Effect of Device and Cable Output Impedance

on Output Module Accuracy. . . . . . . . . . . . . . . . . . . . . 2-11

Wiring the Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

1790D-N4C0, 1790D-N4V0 Analog 4 Input Base D-Shell

Modules Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

1790D-TN4C0, 1790D-TN4V0 Analog 4 Input Base Modules

Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

1790D-N0C2, 1790D-N0V2 Analog 2 Output Base D-Shell

Modules Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

1790D-TN0C2, 1790D-TN0V2 Analog 4 Input Base Modules

Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18

i Publication 1790-UM001A-EN-P - March 2002

Table of Contents ii

Module Data, Status, and Channel Configuration for Analog Input Modules

Module Data, Status, and Channel Configuration for Analog Output Modules

Chapter 3

Analog Input Image . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Analog Input Data File . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Analog Input Data File With Discrete Input Expansion

Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Analog Input Data Format . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Configuring Analog Input Module . . . . . . . . . . . . . . . . . . . 3-7

Configuring Analog Modules With RSNetWorx . . . . . . . . . . 3-8

Chapter 4

Analog Output Image. . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Analog Output Data File . . . . . . . . . . . . . . . . . . . . . . . 4-2

Analog Output Data File With Discrete Output Expansion

Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Analog Output Data Format. . . . . . . . . . . . . . . . . . . . . . . . 4-7

Output Fault and Idle States . . . . . . . . . . . . . . . . . . . . . . . 4-7

Configuring Analog Output Module . . . . . . . . . . . . . . . . . . 4-8

Using RSNetWorx for DeviceNet. . . . . . . . . . . . . . . . . . 4-8

Module Diagnostics and Troubleshooting

Specifications

Chapter 5

Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Indicator Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Activating Devices When Troubleshooting . . . . . . . . . . 5-2

Stand Clear of the Machine. . . . . . . . . . . . . . . . . . . . . . 5-2

Program Alteration. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Safety Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Module Operation vs. Channel Operation . . . . . . . . . . . . . 5-3

Power-up Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Module Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Network Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Channel Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Out-of-Range Detection (Input Modules Only) . . . . . . . 5-4

Open-Circuit Detection (Input Module Only) . . . . . . . . 5-4

Analog Input Module Error Definition Table. . . . . . . . . . . . 5-5

Module Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

Channel LED Indicator Operation . . . . . . . . . . . . . . . . . . . 5-6

Contacting Rockwell Automation . . . . . . . . . . . . . . . . . . . . 5-7

Appendix A

DeviceNet Analog Base Terminal Block . . . . . . . . . . . . A-1

4-Channel Analog Current Input Module. . . . . . . . . . . . A-3

2-Channel Analog Current Output Module . . . . . . . . . . A-4

4-Channel Analog Voltage Input Module. . . . . . . . . . . . A-5

2-Channel Analog Voltage Output Module . . . . . . . . . . A-6

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PROFIBUS Modules Installation, Wiring, Module Data, Status and Channel Configuration

Glossary

Table of Contents iii

Appendix B

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Module Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

Prevent Electrostatic Discharge . . . . . . . . . . . . . . . . . . . B-2

Environment and Enclosure . . . . . . . . . . . . . . . . . . . . . B-3

Remove Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Reducing Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Protecting the Circuit Board from Contamination. . . . . . B-4

Installing CompactBlock LDX I/O . . . . . . . . . . . . . . . . . . . B-5

Set the Station Address on the Base Block . . . . . . . . . . B-5

Mount the Base Block . . . . . . . . . . . . . . . . . . . . . . . . . B-5

Connect the PROFIBUS DP Terminal Connector . . . . . . B-8

Connect Power to the Block. . . . . . . . . . . . . . . . . . . . . B-9

Connecting I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . B-10

General Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . B-10

Guidelines for Input Modules . . . . . . . . . . . . . . . . . . . B-10

Guidelines for Output Modules . . . . . . . . . . . . . . . . . B-10

Wiring the Modules . . . . . . . . . . . . . . . . . . . . . . . . . . B-11

1790P-TN4C0 Data Structure . . . . . . . . . . . . . . . . . . . . . . B-15

Analog Input Image . . . . . . . . . . . . . . . . . . . . . . . . . . B-15

1790P-TNOC2 Data Structure. . . . . . . . . . . . . . . . . . . . . . B-16

Analog Output Image. . . . . . . . . . . . . . . . . . . . . . . . . B-16

Output Fault and Idle States . . . . . . . . . . . . . . . . . . . . . . B-16

Configuring PROFIBUS Analog Modules . . . . . . . . . . . . . B-16

Configuring Analog Modules with the SST PROFIBUS

Configuration Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-17

Downloading Configuration. . . . . . . . . . . . . . . . . . . . . . . B-21

PROFIBUS DP Specifications . . . . . . . . . . . . . . . . . . . . . . B-24

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-25

Index

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Table of Contents iv

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Chapter

Overview

This chapter explains how analog data is used, and describes CompactBlock LDX analog input and output modules. Included is information about:

• the use of analog I/O

• the modules’ hardware and diagnostic features

• an overview of the analog input system operation

• an overview of the analog output system operation

How to Use Analog I/O

Analog refers to the representation of numerical quantities by the measurement of continuous physical variables. Analog applications are present in many forms. The following application shows a typical use of analog data.

In this application, the processor controls the amount of fluid in a holding tank by adjusting the valve opening. The valve is initially open 100%. As the fluid level in the tank approaches the preset point, the processor modifies the output to close the valve 90%, 80%, and so on, continuously adjusting the valve to maintain the fluid level.

Analog output wired to valve

Valve

Controller

Level Sensor

Analog input wired

to tank

Analog I/O

Module

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1-2 Overview

General Description

The analog input module converts and digitally stores analog data for retrieval by controllers, such as the SLC-500 programmable controller. The module supports connections from any combination of up to four voltage or current analog sensors. The four high-impedance input channels can be wired as single-ended inputs.

The output module provides two single-ended analog output channels, either voltage or current, depending on the module selected.

Table 1.1 lists the CompactBlock LDX module types and corresponding operating ranges:

Table 1.1 CompactBlock LDX Module Types and Operating Ranges

CompactBlock LDX

Module

1790D-N4CO

1790D-TN4CO

1790D-NOC2

1790D-TNOC2

Type: Operating Range:

Current Input 4-20mA

0-20mA

Current Output 0-20mA

1790D-N4VO

1790D-TN4VO

1790D-NOV2

1790D-TNOV2

Voltage Input 0-10V dc

Voltage Output 0-10V dc

Each analog base module supports up to two CompactBlock LDX discrete expansion modules.

Publication 1790-UM001A-EN-P - March 2002

DIN rail slot

DeviceNet network connector

Overview 1-3

Hardware Features

The modules contain either removable D-shell connectors or fixed terminal blocks. The CompactBlock LDX four input channels are single-ended. The CompactBlock LDX two output channels are also single-ended. Module configuration is normally done via the

controller’s programming software. In addition, some controllers support configuration via the user program.

Figure 1.1 shows the CompactBlock LDX analog modules’ hardware features.

Figure 1.1

Node address switches

Panel mount hole

Expansion connector under cover

Module indicators

Panel mount hole

Analog I/O connections (D-shell shown)

43218

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1-4 Overview

General Diagnostic Features

The CompactBlock LDX modules contain 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 5, Module Diagnostics and Troubleshooting.

System Overview

The modules communicate to the controller through the DeviceNet network. Module power is derived from DeviceNet. Additionally, the analog I/O requires 24V dc field power separate from DeviceNet. CompactBlock LDX analog bases support up to two discrete LDX expansion modules.

System Operation

At power-up, the analog base 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 power-up diagnostics, the module status LED is turned on.

After power-up checks are complete, the module waits for valid channel configuration data. If an invalid configuration is detected, the module generates a configuration error. Once a channel is properly configured and enabled, it begins the analog-to-digital or digital-to-analog conversion process.

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Overview 1-5

Module Operation

Input Module

The input module’s input circuitry consists of four analog inputs multiplexed into a single analog-to-digital (A/D) converter. The A/D converter reads the selected input signal and converts it to a digital value that is presented to the network. The multiplexer sequentially switches each input channel to the module’s A/D converter. Figure 1.2 on page 1-5 shows a block diagram of the circuitry.

Figure 1.2

Isolation

Input 0

Input 1

Input 2 Input 3

24V dc Field Power

Data

Signal

A/D

Control

Multiplexer

Select

Analog power supply

Analog power

Optocouplers

Microcontroller

DeviceNetXCVR

43219

Each time the input module reads a channel, the module tests that analog data value for an overrange or underrange condition. If such a condition is detected, a unique bit is set in the channel status word. The channel status word is described in Chapter 4, Module Data, Status, and Channel Configuration for Analog Output Modules.

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1-6 Overview

Output 0

Analog output

Output Module

The output module uses a digital-to-analog (D/A) converter to read the digital output data from the network and convert it to an analog output signal. Figure 1.3 below shows a block diagram of the circuitry.

Figure 1.3

Isolation

Optocouplers

Data

Output 1

24V dc Field Power

Analog output

Analog power supply

D/A

Control

Analog power

Microcontroller

DeviceNetXCVR

43220

Publication 1790-UM001A-EN-P - March 2002

Installation and Wiring

This chapter tells you how to:

• determine the power requirements for the modules

• avoid electrostatic damage

• install the module

• wire the module’s terminal block

• wire input devices

• wire output devices

Chapter

Power Requirements

Module Installation

The modules receive power through the DeviceNet network and from an auxilary 24V dc field supply. The maximum power drawn by the modules is shown in Table 2.1.

Table 2.1 CompactBlock LDX Module Power Requirements

Voltage Range: Power:

DeviceNet Power: 11-28.8 V dc 1.2W @ 28.8V dc

Auxilary 24V dc Field Power: 21.6-26.4V dc 1.5W @ 26.4V dc

CompactBlock LDX is suitable for use in an industrial environment when installed in accordance with these instructions. Specifically, this equipment is intended for use in clean, dry environments (Pollution

(1)

degree 2

) and to circuits not exceeding Over Voltage Category II

(IEC 60664-1).

(3)

(2)

(1)

Pollution Degree 2 is an environment where, normally, only non-conductive pollution occurs except that occasionally a temporary conductivity caused by condensation shall be expected.

(2)

Over Voltage Category II is the load level section of the electrical distribution system. At this level transient voltages are controlled and do not exceed the impulse voltage capability of the product’s insulation.

(3)

Pollution Degree 2 and Over Voltage Category II are International Electrotechnical Commission (IEC) designations.

1 Publication 1790-UM001A-EN-P - March 2002

2-2 Installation and Wiring

Prevent Electrostatic Discharge

ATTENTION

Electrostatic discharge can damage integrated circuits or semiconductors if you touch analog I/O module bus connector pins or the terminal block on the input module. Follow these guidelines when you handle the module:

• Touch a grounded object to discharge static potential.

• Wear an approved wrist-strap grounding device.

• Do not touch the bus connector or connector pins.

• Do not touch circuit components inside the module.

• If available, use a static-safe work station.

• When it is not in use, keep the module in its box.

Environmnet and Enclosure

ATTENTION

This equipment is intended for use in a Pollution Degree 2 industrial environment, in overvoltage Category II applications (as defined in IEC publication 60664-1), at altitudes up to 2000 meters without derating.

This equipment is considered Group 1, Class A industrial equipment according to IEC/CISPR Publication 11. Without appropriate precautions, there may be potential difficulties ensuring electromagnetic compatibility in other environments due to conducted as well as radiated disturbance.

This equipment is supplied as "open type" equipment. It must be mounted within an enclosure that is suitably designed for those specific environmental conditions that will be present and appropriately designed to prevent personal injury resulting from accessibility to live parts. The interior of the enclosure must be accessible only by the use of a tool. Subsequent sections of this publication may contain additional information regarding specific enclosure type ratings that are required to comply with certain product safety certifications.

Publication 1790-UM001A-EN-P - March 2002

See NEMA Standards publication 250 and IEC publication 60529, as applicable, for explanations of the degrees of protection provided by different types of enclosure. Also, see the appropriate sections in this publication, as well as the Allen-Bradley publication 1770-4.1 ("Industrial Automation Wiring and Grounding Guidelines"), for additional installation requirements pertaining to this equipment.

Remove Power

Installation and Wiring 2-3

General Considerations

ATTENTION

Remove power before removing or inserting this module or an expansion module. When you remove or insert a module with power applied, an electrical arc may occur. An electrical arc can cause personal injury or property damage by:

• sending an erroneous signal to your system’s field

devices, causing unintended machine motion

• causing an explosion in a hazardous environment

Electrical arcing causes excessive wear to contacts on both the module and its mating connector and may lead to premature failure.

Reducing Noise

Most applications require installation in an industrial enclosure to reduce the effects of electrical interference. Analog inputs and outputs are highly susceptible to electrical noise. Electrical noise coupled to the analog inputs will reduce the performance (accuracy) of the module.

Group your modules in the enclosure to minimize adverse effects from radiated electrical noise and heat. Consider the following conditions when selecting a location for the analog module. Position the module:

• away from sources of electrical noise such as hard-contact

switches, relays, and AC motor drives

• away from modules which generate significant radiated heat.

In addition, route shielded, twisted-pair analog input and output wiring away from any high voltage I/O wiring.

Protecting the Circuit Board from Contamination

The printed circuit boards of the analog modules must be protected from dirt, oil, moisture, and other airborne contaminants. To protect these boards, the system must be installed in an enclosure suitable for the environment. The interior of the enclosure should be kept clean and the enclosure door should be kept closed whenever possible.

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2-4 Installation and Wiring

Installing CompactBlock LDX I/O

Follow these steps to install the block:

1. Set the Node Address on the Base Block

2. Mount the Base Block

3. Mount the Optional Expansion Blocks

4. Connect the DeviceNet Cable

Set the Node Address on the Base Block

Each base block comes with its internal program set for node address

63. To reset the node address, adjust the switches on the front of the block. The two switches are most significant digit (MSD) and least significant digit (LSD). The switches can be set between 00 and 63.

The rotary switches are read at block power up only. Switch settings between 64 and 99 cause the block to use the last valid node address stored internally

Node Address is set to 11

Figure 2.1

NODE ADDRESS

MOD NET

STATUS

LSDMSD

43216

The node address may also be set through RSNetWorx for DeviceNet or a similar configuration tool. When software configuration is used for the node address, the switches must be set between 64 and 99.

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Installation and Wiring 2-5

Mount the Base Block

You can mount the base block to a panel or DIN rail. We recommend that you ground the panel or DIN rail before mounting the block.

IMPORTANT

WARNING

The analog base module can accommodate a maximum of two discrete expansion modules.

When used in a Class I, Division 2, hazardous location, this equipment must be mounted in a suitable enclosure with proper wiring method that complies with the governing electrical codes.

Panel Mounting

1. Place the block against the panel where you want to mount it.

2. Gently pull and position the expansion cover to the left.

3. Place a center punch, nail or similar device through the

mounting holes in the block and make two marks on the panel (lower left and upper right corners of the module).

4. Remove the block and drill two holes in the panel to

accommodate each of the mounting screws.

5. Replace the block on the panel and place a screw through each of the

two mounting holes. Tighten the screws until the block is firmly in place.

95 mm

3.74 in

CompactB

1790-16BVOX

41 mm

1.6 in

EXPANSION UNIT

16 INPUTS-DCPOWER

Expansion Cover

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2-6 Installation and Wiring

Compact

PULL

Compact

PULL

Compact

PULL

Compact

Block LDX

PULL

Compact

PULL

Compact

PULL

Compact

PULL

DIN Rail Mounting

1. Hook the top of slot of the block over the DIN Rail.

Pull down on the locking lever while pressing the block against the rail.

Locking Lever

3. Push up on the locking lever to secure the block to the rail

when block is flush against the rail.

Mount the Optional Expansion Blocks

Mount the expansion block by connecting it to a previously-installed CompactBlock LDX I/O base or expansion block.

Beginning with the base block, you can mount your expansion blocks horizontally or vertically:

• horizontally (left to right) - add expansion blocks in a

end-to-end configuration

• vertically (up or down) - add expansion blocks either up or

down in a back-to-back configuration. In this configuration, you must use the optional 15cm ribbon cable (1790-15CMCBL) and alternately position the blocks in a right-side up, upside-down fashion.

Compact

Block LDX

Compact

Block LDX

EXPANSION UNIT

PULL

RIGHT SIDE UP

Horizontal mounting

EXPANSION UNIT

PULL

RIGHT SIDE UP

Vertical mounting

Compact

Block LDX

PULL

Compact

EXPANSION UNIT

RIGHT SIDE UP

UPSIDE DOWN

Compact

Block LDX

Compact

EXPANSION UNIT

PULL

RIGHT SIDE UP

Block LDX

PULL

EXPANSION UNIT

Block LDX

PULL

Compact

Block LDX

The longer expansion cable (1790-15CMCBL) will allow up to 7cm of space in between blocks.

PULL

EXPANSION UNIT

PULL

RIGHT SIDE UP

You can mount your blocks on a panel or DIN rail as described in the previous section.

Publication 1790-UM001A-EN-P - March 2002

Installation and Wiring 2-7

Connect the DeviceNet Cable

Follow these procedures when connecting the DeviceNet cable to the base block.

The required DeviceNet connector is not supplied with the block you must purchase it separately. There are three types of connectors that you can order directly from Rockwell Automation or your local distributor:

• 1799-DNETCON - 5-position open style connector

• 1799-DNETSCON - 5-position open style connector with locking

screws

• 1799-DNC5MMS - 5-position open style to 12mm connector with

locking screws

WARNING

If you connect or disconnect the DeviceNet cable with power applied to this module or any device on the network, an electrical arc can occur. This could cause an explosion in hazardous location

installations.

Be sure that power is removed or the area is nonhazardous before proceeding.

Connect the DeviceNet wiring (drop line) to one of the DeviceNet connectors as shown below. A color-coded wiring diagram is also printed next to the connector on the left side of the module

CompactBlock LDX

Wiring Diagram for 1799-DNETCON

V+ Red

Can_H White

Drain/Shield

V+ Red

V- Black

Wiring Diagram for 1799-DNC5MMS

Can_L Blue

V- Black

Drain/Shield

Can_H White

Can_L Blue

Once you have properly wired the drop line to the connector, attach the connector to the block. If applicable, use the locking screws on the connector to fasten it to the block.

Publication 1790-UM001A-EN-P - March 2002

2-8 Installation and Wiring

I/O System Wiring Guidelines

Consider the following when wiring your system:

General

• All module commons (COM) are connected in the analog

module. The analog common (COM) is not connected to earth ground inside the module.

• Channels are not isolated from each other.

• Do not use the analog module’s NC terminals as connection

points.

• To ensure optimum accuracy, limit overall cable impedance by

keeping your cable as short as possible. Locate the I/O system as close to your sensors or actuators as your application will permit.

• Use Belden™ 8761, or equivalent, shielded wire.

• Keep shield connection to ground as short as possible.

• Under normal conditions, the drain wire and shield junction

must be connected to earth ground via a panel or DIN rail mounting screw at the analog I/O module end.

(1)

Input Modules

• If multiple power supplies are used with analog inputs, the

power supply commons must be connected together.

• The module does not provide loop power for analog inputs. Use

a power supply that matches the input transmitter specifications.

Output Modules

• Voltage outputs (CH0 and CH1) of the 1790D-NOV2/TNOV2

modules are referenced to COM. Load resistance for a voltage output channel must be equal to or greater than 1K

• Current outputs (CH0 and CH1) of the 1790D-NOC2/TNOC2

modules source current that returns to COM. Load resistance for a current output channel must remain between 0 and 600

Ω.

Publication 1790-UM001A-EN-P - March 2002

(1)

In environments where high-frequency noise may be present, it may be necessary to directly ground cable shields to earth at the module end and via a 0.1µF capacitor at the sensor end.

Installation and Wiring 2-9

Effect of Transducer/Sensor and Cable Length Impedance on Voltage Input Accuracy

For voltage inputs, the length of the cable used between the transducer/sensor and the module can affect the accuracy of the data provided by the module.

RcRs

Where:

V in

Rc = DC resistance of the cable (each conductor) depending on cable length

Rs = Source impedance of analog transducer/sensor output

Ri = Impedance of the voltage input (500K

Ω for

1790D-N4VO/TN4VO)

Vs = Voltage source (voltage at the transducer/sensor input device)

Vin = Measured potential at the module input

%Ai = Percent added inaccuracy in a voltage-based system due to source and cable impedance.

Ri Vs

Vin

-------------------------------------------------------

Rs 2 Rc×()Ri++[]

×[]

Publication 1790-UM001A-EN-P - March 2002

2-10 Installation and Wiring

For example, for Belden 8761 two conductor, shielded cable:

Rc = 16

Ω/1000 ft

Rs = 0 (ideal source)

Vin



%Ai 1

Table 2.2 Effect of Cable Length on Input Accuracy

Length of Cable (m) dc resistance of the

cable, Rc (

50 2.625 0.00105%

100 5.25 0.00210%

200 10.50 0.00420%

300 15.75 0.00630%

---------

–



100×=

Ω)

Accuracy impact at the

input module

As input source impedance (Rs) and/or resistance (dc) of the cable (Rc) get larger, system accuracy decreases. If you determine that the inaccuracy error is significant, implementing the following equation in the control program can compensate for the added inaccuracy error due to the impedance of the source and cable.

Vs Vin

Rs 2 Rc

-------------------------------------------------------

×=

×()Ri++[]

Publication 1790-UM001A-EN-P - March 2002

TIP

In a current loop system, source and cable impedance do not impact system accuracy.

Installation and Wiring 2-11

Effect of Device and Cable Output Impedance on Output Module Accuracy

The maximum value of the output impedance is shown in the example below, because it creates the largest deviation from an ideal voltage source.

Rs Rc

–

Where:

Vload Rload

43266

Rc = DC resistance of the cable (each conductor) depending on cable length

Rs = Source impedance of 1790D-NOV2/TNOV2 (0.5

= Impedance of the load device

load

Ω)

Vs = Voltage at the output of 1790D-NOV2/TNOV2

= Measured potential at the load device

load

%Ai = Percent added inaccuracy in a voltage-based system due

to source and cable impedance.

x Vs]

load

[Rs + (2 x Rc) + R

load

]

For example, for Belden 8761 two conductor, shielded cable and a 1790D-NOV2/TNOV2 module:

Rc = 16

Ω/1000 ft

Rs = 0.5

%AV

load

Ω

= (1 - ) x 100

load

Publication 1790-UM001A-EN-P - March 2002

2-12 Installation and Wiring

Table 2.3 Effect of Output Impedance and Cable Length on Accuracy

Length of Cable

(m)

dc resistance of

the cable, Rc (

Ω)

Accuracy impact at the load

Ω 10,000Ω 100,000Ω

1,000

1 0.0525 0.0605% 0.00605% 0.000605%

10 0.525 0.155% 0.0155% 0.00155%

50 2.625 0.575% 0.0575% 0.00575%

100 5.25 1.1% 0.11% 0.011%

As output impedance (Rs) and/or resistance (dc) of the cable (Rc) get larger, system accuracy decreases. If you determine that the inaccuracy error is significant, implementing the following equation in the control program can compensate for the added inaccuracy error due to the impedance of the output module and cable.

+ (2 x Rc) + R

Vs = V

TIP

load

In a current loop system, source and cable impedance do not impact system accuracy.

load

]

Publication 1790-UM001A-EN-P - March 2002

Wiring the Modules

Installation and Wiring 2-13

ATTENTION

To prevent shock hazard, care should be taken when wiring the module to analog signal sources. Before wiring any analog module, disconnect power from the system power supply and from any other source to the analog module.

After the analog module is properly installed, follow the wiring procedure below. To ensure proper operation and high immunity to electrical noise, always use Belden™ 8761 (shielded, twisted-pair) or

equivalent wire.

ATTENTION

Never connect a voltage or current source to an analog output channel.

signal wire

drain wire

cable

foil shield

signal wire

Cut foil shield and drain wire

signal wire

Publication 1790-UM001A-EN-P - March 2002

2-14 Installation and Wiring

To wire your module follow these steps.

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 (5

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

ATTENTION

Be careful when stripping wires. Wire fragments that fall into a module could cause damage at power up.

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

together.

Under normal conditions, this drain wire and shield junction must be connected to earth ground, via a panel or DIN rail mounting screw at the analog I/O module end. Keep the length of the drain wire as short as possible.

In environments where high frequency noise may be present, it may be necessary to ground the cable shields to earth at the module and via a 0.1µF capacitor at the sensor end for analog inputs and at the load end for analog outputs.

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

back to the cable.

Publication 1790-UM001A-EN-P - March 2002

5. Connect the signal wires to the terminal block as shown in

analog input wiring on page 2-15 and page 2-16 and analog output wiring on page 2-17 and page 2-18.

6. Connect the other end of the cable to the analog input or output

device.

7. Repeat steps 1 through 5 for each channel on the module.

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