Rockwell Automation 1791-XXXX User Manual

1791 Analog Block I/O Input/Output Modules

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 this control
equipment must satisfy themselves that all necessary steps have been taken
to assure that each application and use meets all performance and safety
requirements, including any applicable laws, regulations, codes and
standards.

The illustrations, charts, sample programs and layout examples shown in
this guide are intended solely for 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
which 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
in part, without written permission of Allen–Bradley Company, Inc. is
prohibited.

Throughout this manual we make notes to alert you to possible injury to
people or damage to equipment under specific circumstances.

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

Attention helps you:

- Identify a hazard

- Avoid the hazard

- recognize the consequences

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

Important: We recommend you frequently backup your application
programs on appropriate storage medium to avoid possible data loss.

Summary of Changes

Summary of Changes

Summary of Changes

This release of the publication contains new and updated information from
the last release.

New Information

This release includes information on new block I/O modules now
available. This information was not included in the previous release of
this publication. The modules are:

1791-NDV – 24V dc Analog Block I/O (voltage outputs)
1791-NDC – 24V dc Analog Block I/O (current outputs)

Updated Information

Generally, change bars (as shown to the right of this paragraph) are used to
show new or significantly revised copy. Certain additions, such as adding
octal numbering or corrected typographical errors, are not shown by
change bars.

S-1

Table of Contents

Summary of Changes S1. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Using This Manual P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Purpose
Audience P1
Vocabulary P1
Manual Organization P1
Block I/O Products Covered by this Publication P2

of Manual

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . .

P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introducing Block I/O 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter
General Description 11
How
Inputs 14
Scaling 16
Outputs 18

Objectives

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Block I/O Fits in a PLC System

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13. . . . . . . . . . . . . . . . . . . . . . .

Installing Block I/O 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter
Preinstallation Considerations 21
Installing
Connecting Wiring 24
Termination Resistor 213
Remote
Extended
Compatibility of 1771 I/O Products with Extended Node Numbers 215
Selecting

Objectives

the Block I/O

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I/O Link

Node Capability

Remote I/O Link Speed

21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . .

23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

213. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

214. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. .

215. . . . . . . . . . . . . . . . . . . . . . . .

Configuring Your Block I/O for PLC Family

Programmable Controllers 31. . . . . . . . . . . . . . . . . . . . .

Chapter
Setting
Module Scan Time 37

Objectives

the Configuration Switches

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31. . . . . . . . . . . . . . . . . . . . . . . .

Analog Block Applications Using Block Transfers 41. . . . . . .

Chapter
Reading Data and Status from the Module 41
Block Transfer Read Data Format 41
Configuring

Objectives

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . .

the Module and Setting Outputs with Block T

Instructions 43

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ransfer Write

41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contentsii

Analog Block Applications Using Discrete Transfers 51. . . . .

Chapter
Discrete Data Transfer 51
Input Data Format 51
Output Data Format 52

Objectives

51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Programming Your Analog Block I/O Module 61. . . . . . . . . . .

Chapter
Block Transfer Programming 61
PLC3 Program Example 62
PLC5 and PLC-5/250 Program Example 63
Sample Programs for Analog Block 64
PLC3 Family Processors 64
PLC5 Family Processors 65

Objectives

61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Module Calibration 71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter
Tools and Equipment 71
Calibrating your Module 71

Objective

71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting 81. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter
Module Indicators 81

Objectives

81. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Specifications A1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Using This Manual

Preface

Purpose

of Manual

Audience

Vocabulary

Manual Organization

This manual shows you how to use your block I/O with an Allen-Bradley
programmable controller. It helps you:

install your module
program your module
troubleshoot your module

You must be able to program and operate an Allen-Bradley programmable
controller (PLC) to make efficient use of block I/O modules.

We assume that you know how to do this in this manual. If you do not,
refer to the appropriate PLC programming and operations manual before
you attempt to program this module.

In this manual, we refer to:

the block I/O module as the “block” or the “module”
the programmable controller as the “controller” or “processor”

This manual is divided into eight chapters. The following chart shows each
chapter with its corresponding title and brief overview of the topics
covered in that chapter.

Chapter Title Topics Covered

1 Introducing Block I/O

2 Installing Block I/O

3

4

5

6

7 Module Calibration How to calibrate analog block I/O

8 Troubleshooting

Appendix A Specifications Specifications for the block I/O modules

Configuring Your Block I/O for PLC
Family Programmable Controllers

Analog Block Applications using Block
Transfers

Analog Block Applications using Discrete
Transfers

Programming Your Analog Block I/O
Module

Description of the modules, including general and
hardware features

Module power requirements, location, and wiring
information

How to set the configuration switches and address
the block I/O

How to use block transfer programming with your
block I/O

How to use discrete transfer with your block I/O

Programming examples for analog block I/O and
PLC family controllers

How to use the indicators to troubleshoot your block
I/O module

P-1

Preface

Using This Manual

Block

I/O Products Covered

by this Publication

Related Publications

This publication covers the following analog block I/O products:

Catalog Number Power Supply Voltage Inputs Outputs Description

1791N4V2 120V ac 4 2 analog - 4 input, 2 voltage output

1791N4C2 120V ac 4 2 analog - 4 input, 2 current output

1791NDV 24V dc 4 2 analog - 4 input, 2 voltage output

1791NDC 24V dc 4 2 analog - 4 input, 2 current output

For a list of publications with information on Allen-Bradley products,
consult our publication index (SD499).

P-2

Introducing Block I/O

y

Chapter

1

Chapter

Objectives

General Description

In this chapter, you will learn what analog block I/O is, its features, and
how it functions.

Block I/O consists of small, self-contained remote I/O devices complete
with power supply, programmable controller interface, input/output
connections and signal conditioning circuitry. Table 1.A is a list of block
I/O modules covered in this publication.

Table 1.A

of Block I/O

Types

Catalog Number Power Supply Voltage Inputs Outputs Description

1791N4V2 120V ac 4 2 analog - 4 input, 2 voltage output

1791N4C2 120V ac 4 2 analog - 4 input, 2 current output

1791NDV 24V dc 4 2 analog - 4 input, 2 voltage output

1791NDC 24V dc 4 2 analog - 4 input, 2 current output

The analog blocks are compatible with PLC-2, PLC-3, PLC-5/250 and



PLC-5
modular controllers. Refer to the table below for information on using
block I/O with various Allen-Bradley programmable controllers.

family programmable controllers, and the SLC 5/02 (or greater)

If You are Using: You must use:

PLC2 family programmable controller

PLC3 family programmable controller

PLC5 family programmable controller

PLC5/250 programmable controller

SLC 500 programmable controller 1747SN remote I/O scanner

The analog blocks communicate via block transfer or discrete transfer with
any Allen-Bradley programmable controller that connects to the remote
I/O network. The analog blocks communicate with SLC family controllers
using discrete transfer.

Each analog block has four independent inputs, which can be configured as
either all voltage inputs or all current inputs. The block contains a 24V dc
current limited voltage source for accommodating loop-powered current
transducer inputs.

1771SN subI/O scanner or

1772SD and SD2 remote I/O scanners

Block attaches directly to controller

1-1

Chapter 1

Introducing Block I/O

Analog block outputs are configured at the factory for either a current
output or a voltage output. Outputs are not user-configurable.

Figure 1.1 shows the physical features of the block I/O.

Figure 1.1

Features of the Analog Block I/O Modules (1791N4V2 shown)

Major

1791N4V2

ANALOG

POWER

COMM

FAULT

BLOCK

Indicators

1

Removable

Terminal Strip for

Input, Output, Remote

I/O and Power

Connections

Switch
Assemblies

Equipment
Grounding

Stud

30

2 mounting holes
for 1/4inch screws

12631I

Terminal Strip - Remote I/O link, power and input/output connections are
made to the removable terminal strip for easy connection of wiring.

Switch Assembly - The modules contain two switch assemblies. Use these
assemblies to make the following settings:

I/O rack number
starting I/O group
communication rate
last I/O group
last state
transfer type
processor restart/lockout

1-2

Status Indicators - Indicators display the status of module power,
communication and fault. Use these indicators to help in troubleshooting.

Chapter 1

Introducing Block I/O

How

Block I/O Fits in a

PLC System

Programmable
Controller
or Scanner

Block I/O is a complete I/O interface that includes the functionality of the
I/O rack, adapter, power supply, and I/O module in a single unit. Connect
sensors and actuators to the module and use the remote I/O cable to
connect the block I/O to your programmable controller.

Connect the block I/O to your remote I/O link as you would any other
device. Input and output data is scanned asynchronously and transferred
back and forth between the block and the programmable controller using
either block transfer or discrete transfer. When using block transfer
(Figure 1.2), the block looks like a 1/4 I/O rack to the processor (two
words of input image table memory and two words of output image table
memory). Block transfer provides the most efficient use of your data table
image memory, and allows access to all implemented user functions of
the block.

Figure 1.2

I/O Connection in a PLC System using block transfer

Block

Block I/O  each block

1/4

is 1/4 I/O rack

1/4

1/4

+

Blocks are daisychained to
a programmable controller or
a scanner

1/4

+

+

= 1 I/O Rack

10828I

1-3

Chapter 1

Introducing Block I/O

Discrete transfer (Figure 1.3) is intended to be used with controllers which
do not have block transfer capability. However, discrete transfer can be
used with any PLC family controller. When using discrete transfer, the
block looks like a 1/2 I/O rack to the controller (four words of input image
table memory and four words of output image table memory). Note that
certain alarms and user scaling features are not available when using
discrete transfer.

Figure 1.3

I/O Connection in an SLC System using discrete transfer

Block

Block I/O  each block

1747SN Remote I/O
Scanner Module

1/2

is 1/2 I/O rack

1/2

Inputs

Simplified Schematic

Channel 0 Input

inV0

inI0

249Ω

RET in0

GND in0

20MΩ

20MΩ

Analog Input

1

Common

+

= 1 I/O Rack

Blocks are daisychained to
a scanner

A simplified schematic of the input circuit of one input channel is
shown below.

Analog Multiplexer

ATTENTION: The 249 ohm
input current shunt is rated at

0.25 Watts. Do not exceed this
power rating or apply more
than 6V across the resistor

Channel 0

Channel 1

Channel 2

Channel 3

Instrumentation

Amplifier

+

-

Analog Input

1

Common

10828I

A/D

12501-I

1-4

Inputs have selectable input ranges as shown below.

Application Input Range Resolution

voltage +10V 14 Bits

voltage or current +5V 14 Bits

voltage 0 to 10V 14 Bits

voltage or current 0 to 5V 14 Bits

Chapter 1

Introducing Block I/O

Voltage Input

Voltage inputs can be either single-ended or differential. In the voltage
mode, a signal applied between inV0 and the combination of RET in0
shorted to GND in0 provides a single-ended input mode. A signal applied
between inV0 and RET in0 provides a differential input mode. The four
terminals for ground are internally connected together to form the analog
input common. In either input mode (single-ended or differential) the
common mode voltage between any input terminal and analog input
common cannot exceed 11V or unreliable operation will occur. The figures
below show examples of differential input mode and single-ended input
mode.

10V

Differential Input Mode Singleended Input Mode

inV0

inI0

(no connection)

RET in0

GND in0

10V inV0

Current Input

When using the 0–5V or +5V range, an internal precision 249Ω shunt is
provided on each input. Input current is measured when the I
terminals are connected together. To get the proper input voltages, you
must indicate that the current shunt is connected when you configure the
module at powerup. A +24V power supply is provided for two-wire
current transducers.

I

5V

Current Input

inV0

inI0

RETin0

inI0

(no connection)

RETin0

GNDin0

and V

IN

IN

GNDin0

Each range setting has a margin of 2.5% to allow for compensation of
system or calibration inaccuracies.

1-5

Chapter 1

Introducing Block I/O

This is illustrated using the +10V scale below:

14 Bits

Resolution

Margin

13.96 Bits

Margin

Input Signal

I1 I2 I3 I4 I5

Nominal Range

In the above scale, input signals 1 thru 5 produce corresponding internal
analog to digital converter (ADC) binary counts. A full scale (FS) voltage
input produces an internal count of 16383 (input signal 1), while a bottom
scale (BS) voltage input produces an internal count of 0000 (input 5).
During calibration, the module’s representation of the counts are adjusted
so a voltage of nominal full scale (NFS) will produce a count shown as
input signal 2 while the nominal bottom scale voltage (NBS) produces a
count shown as input signal 4. For each range scale, the input voltage
which produces the ADC count of input signals 1 thru 5 in the above scale
are shown below:

Input Signal +/-10V 0-10V +/-5V 0-5V

I1 10.25V (FS) 10.25V (FS) 5.125V (FS) 5.125V (FS)

I2 +10.000V (NFS) 10.00V (NFS) 5.000V (NFS) 5.000V (NFS)

I3 0.000V 5.00V 0.000V 2.500V

I4 -10.000V (NBS) 0.00V (NBS) -5.000V (NBS) 0.000V (NBS)

I5 -10.25V (BS) -0.25V (BS) -5.125V (BS) -0.125V (BS)

Scaling

1-6

The input data represented at the module is always the internal ADC binary
counts scaled by values set in the maximum (S

) and minimum (S

max

min

)
scaler value using a two point scaling method. The input voltage which
produces input signal 2 (V
signal 4 (V

Scaling

Input Signal

Voltage

) is equal to S

nbs

Smax

I1 I2 I3 I4 I5

Vnfs

) is always equal to S

nfs

as shown below:

min

, and voltage of input

max

Smin

Vnbs

Chapter 1

Introducing Block I/O

The following equation shows how the module interprets the input data:

Module
where:

data = M x Vin + B

– S

(S

M =

B =

(V

(S

max

nfs

min

– V

x V

(V

min

nbs

nfs

nfs

)

) – (S

)

– V

nbs

max

)

x V

nbs

)

You can choose one of three scaling methods:

binary counts (module sets scalers)
default scaling (module sets scalers)
user scaling (you set scalers)

User scaling is not available when you select discrete transfer mode.

Binary Counts Scaling

Binary counts scaling mode activates when the module powers up. This
mode guarantees the maximum resolution. The module sets the scalers as
shown in the following table:

Scaler +/-10V 0-10V +/-5V 0-5V

S

max

S

min

8191 16383 8191 16383

-8192 0 -8192 0

Default Scaling

Default scaling mode scales inputs to the input stimulus in either millivolts
or microamps. The module sets the scalers as shown in the following
tables:

With Voltage Input Selected

Scaler +/-10V 0-10V +/-5V 0-5V

S

S

With Current Input Selected

Scaler +/-10V 0-10V +/-5V 0-5V

S

S

10,000mV 10,000mV 5000mV 5000mV

max

-10,000mV 0mV -5000mV 0mV

min

max

min

N/A N/A 20000uA 20000uA

N/A N/A -20000uA 0uA

1-7

Chapter 1

Introducing Block I/O

User Scaling

User scaling is available only when using the block transfer mode. This
mode allows you to define S

max

and S

in engineering units in the block

min

transfer write data table. The integer range is 32,767 to –32,768.
Important: If the range of user scaling values is set less than the range of

binary counts scaling values, input resolution is sacrificed.

Scaling Example

Using the +10V range scale, the following illustration shows five possible
input signals.

14 Bits

Resolution

Margin

13.96 Bits

Margin

Outputs

Input Signal

10.25 10 0 -10 -10.25

Nominal Range

The following table shows how the five signals will be scaled using each
of the three scaling methods. In the user scaling column, the S
to represent 5000 and the S

Input Value

Approx. +10.25V 8395 10250 5062

+10.000V 8191 10000 5000 (Smax)

0.000V 0000 00000 2500

-10.000V -8192 -10000 0000 (Smin)

Approx. -10.25V -8396 -10250 -0062

Binary Counts Default User

was set to represent 0.

min

Scaling Method

max

was set

The type of output your block I/O module has depends on its catalog
number:

1791-N4V2 and 1791-NDV have two +10V voltage outputs
1791-N4C2 and 1791-NDC have two 0-20mA current outputs

1-8

For any of the above modules, if your program tries to write a value which
is outside the output range, the output will be clamped at either the
maximum or minimum value. This condition will be indicated in the block
transfer read status word.

V

OUTS

Digital
Output

Opto

Isolation

Isolated Analog
Output Common

Chapter 1

Introducing Block I/O

V

oltage Outputs - 1791N4V2 and 1791NDV

A simplified schematic of a +10V output channel is shown below.

Precision

Operational

Amplifier

DAC

2

+

-

2

V

OUT

V

RET

Note: Schematic does not show overvoltage protection circuits.

The +10V output provides 14 bits of resolution and is capable of driving
loads as small as 1k ohm. The output sacrifices a small amount of the
resolution to provide a margin of 2.5% to allow for system or calibration
inaccuracies as shown below.

Resolution

Output Signal

Scaling

The digital data sent to the output is always scaled by the values set in the
maximum (S
scaling method. When digital data sent equals S
+10.000V and the digital data sent equals S
–10.000V. The following equations shows this relationship:

Isolated Analog

2

Output Common

14 Bits

13.96 Bits

Margin

10.25 10 0 -10 -10.25

Nominal Range

) and minimum (S

max

) scaler values using a two point

min

Isolated Analog

2

Output Common

, the output produces

max

, the output produces

min

12501-I

Margin

Vout

= M x Module Data + B

where:

M =

B =

(Smax – Smin)

10 x (Smax + Smin)

(Smax – Smin)

20V

1-9

Chapter 1

Introducing Block I/O

You can choose one of three scaling methods:

binary counts
default scaling
user scaling

User scaling is not available when you select discrete transfer mode.

The following table shows the output signals produced by various module
data values entered in each of the three scaling methods. In the user scaling
column, S

Output Signal

Approx. +10.25V 8395 10250 5062

was set to 5000 and S

max

Binary Counts

Scaling

was set to 0000.

min

Module Data

Default
Scaling

User

Scaling

+10V 8191 10000 5000 (Smax)

0.000V 0000 00000 2500

-10.00V -8192 -10000 0000 (Smin)

Approx. -10.25V -8396 -10250 -0062

Current Outputs - 1791N4C2 and 1791NDC

A simplified schematic of a 0 to 20mA output channel is shown below.

I

OUTS

Digital
Output

Note: Schematic does not show overvoltage protection circuits.

Opto

Isolation

Isolated Analog
Output Common

DAC

2

Isolated Analog
Output Common

High Side

Current
Monitor

2

+15V

-15V

I

OUT

I

RET

12505-I

1-10

The 0 to 20mA output provides 13 bits of resolution and is capable of
driving loads as large as 1k ohm.

Chapter 1

Introducing Block I/O

The output sacrifices a small amount of the resolution to provide a margin
of 2.5% to allow for system or calibration inaccuracies as shown below.

13 Bits

Resolution

Margin

12.9 Bits

Margin

Input Signal

20.5 20 10 0.0 –0.5

Nominal Range

Scaling

The digital data sent to the output is always scaled by the values set in the
maximum (S
scaling method. When digital data sent equals S

20.000mA and the digital data sent equals S

0.000mA. The following equations shows this relationship:

Iout
where:

You can choose one of three scaling methods:

binary counts
default scaling
user scaling

) and minimum (S

max

= M x Module Data + B

M =

B =

(Smax – Smin)

20mA x (Smax + Smin)

(Smax – Smin)

min

20mA

) scaler values using a two point

, the output produces

max

, the output produces

min

User scaling is not available when you select discrete transfer mode.

The following table shows the output signals produced by various module
data values entered in each of the three scaling methods. In the user scaling
column, S

Output Signal

Nominally +20.5mA 8395 10250 5062

20.000mA 8191 10000 5000 (Smax)

0.000mA 0000 00000 2500 (Smin)

Nominally -0.5mA

1

The actual output can never go negative. However

compensation.

was set to 5000 and S

max

Binary Counts Scaling Default Scaling User Scaling

1

-0396 -00050 -2437

was set to 0000.

min

Module Data

, some of the output range is used to allow for zero of

fset

1-11

Installing Block I/O

1771SN

14 blocks with 150 ohm terminator
PLC2 famil

1772SD, 1772SD2

16 blocks/channel, 28 blocks/scanner

A

PLC3

with 150 ohm terminator. 128 blocks
32 blocks/channel, 64 blocks/scanner

with 2 scanners, 82 ohm terminator
PLC

Chapter

2

Chapter

Objectives

Preinstallation
Considerations

When using and Maximum Capacity



y

In this chapter, you will learn how to mount the block, connect the remote
I/O link, connect the input and output wiring to the block, and terminate
the remote I/O link.

Before installation, you must determine the:

scanner/processor to use
number of blocks on your network
throughput requirements
total distance of the installation
transmission rate desired
external fuses required (if any)

Acceptable combinations are shown in Table 2.A.

Table 2.A
Acceptable







Combinations of Processor and Block I/O

Baud Rate

14 blocks with 150 ohm terminator
and discrete transfer

16 blocks/channel, 28 blocks/scanner
with 150 ohm terminator

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

Used

Maximum

Network Distance

PLC3 family



5 family



ny

1775S5, or SR5 module

PLC5VME (6008LTV)

PLC5/11

scanner module

16 blocks/channel, 64 blocks/scanner
with 150 ohm terminator. 128 blocks
with 2 scanners and 150 ohm
terminator.

32 blocks/channel, 64 blocks/scanner
with 82 ohm terminator. 128 blocks
with 2 scanners, 82 ohm terminator
and extended node addressing.

4 blocks with 150 ohm terminator

4 blocks with 150 ohm terminator

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

230.4K 2,000 cablefeet

57.6K 10,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

230.4K 2,500 cablefeet

2-1

Chapter 2

terminator

16 blocks/channel, 28 blocks per
28 blocks/ch

16 blocks/channel, 60 blocks per
32 blocks/ch

16 blocks/channel, 32 blocks per
32 blocks/ch

16 blocks/channel, 64 blocks per
32 blocks/ch

16 blocks/channel, 32 blocks per
32 blocks/ch

Installing Block I/O

PLC5 family (continued)

PLC5/15

PLC5/20

PLC5/25

PLC5/30

PLC5/40

Maximum CapacityandWhen using

1

12 blocks with 150 ohm terminator 57.6K 10,000 cablefeet

Baud Rate

Used

Maximum

Network Distance

57.6K 10,000 cablefeet

12 blocks with 82 ohm or 150 ohm
terminator

115.2K 5,000 cablefeet

230.4K 2,500 cablefeet

2

16 blocks with 150 ohm terminator,
28 blocks with 82 ohm terminator and

57.6K 10,000 cablefeet

extended node addressing

16 blocks/channel, 28 blocks per
processor with 150 ohm terminator

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

annel, 28 blocks per

processor with 82 ohm terminator

115.2K 5,000 cablefeet

and extended node addressing

230.4K 2,500 cablefeet

16 blocks/channel, 60 blocks per
processor with 150 ohm terminator

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

annel, 60 blocks per

processor with 82 ohm terminator

115.2K 5,000 cablefeet

and extended node addressing

230.4K 2,500 cablefeet

PLC5/40L

PLC5/60

PLC5/60L

16 blocks/channel, 32 blocks per
processor with 150 ohm terminator

annel, 60 blocks per
processor with 82 ohm terminator
and extended node addressing

16 blocks/channel, 64 blocks per
processor with 150 ohm terminator

annel, 92 blocks per
processor with 82 ohm terminator
and extended node addressing

16 blocks/channel, 32 blocks per
processor with 150 ohm terminator

annel, 64 blocks per
processor with 82 ohm terminator
and extended node addressing

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

230.4K 2,500 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

230.4K 2,500 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

230.4K 2,500 cablefeet

2-2

Chapter 2

a 5 50 S e o e sca e

32 blocks/channel, 32

scanners) with 82 ohm terminator
8 block

3

Controller

Module (discrete mode only)

Installing Block I/O

Maximum CapacityandWhen using

16 blocks/channel, 32

Baud Rate

Used

57.6K 10,000 cablefeet

blocks/scanner, (128 blocks with 4
scanners) with 150 ohm terminator

PLC5 family (continued)

PLC5/250  requires
a 5150RS remote scanner

32 blocks/channel, 32
blocks/scanner, (128 blocks with 4
scanners) with 82 ohm terminator
and extended node addressing

SLC5/02 (and greater)
Controller

1747SN Remote I/O Scanner
Module (discrete mode only)

s with 150 ohm terminator

8 blocks with 82 ohm terminator

1

PLC5/15 series A and PLC5/15 series B prior to revision H (B/H) can only address 3 blocks.

2

PLC5/25 revisions prior to A/D can only address 7 blocks.

3

Analog block is 1/2 rack in discrete transfer mode. If you combine analog block and discrete transfer on the same RIO link, the capacity ranges between 8 and 15 blocks.

Installing the Block I/O

Figure 2.1 shows the mounting dimensions for the block I/O module.

115.2K 5,000 cablefeet

57.6K 10,000 cablefeet

115.2K 5,000 cablefeet

230.4K 2,500 cablefeet

57.6K 10,000 cablefeet

3

115.2K 5,000 cablefeet

3

230.4K 2,500 cablefeet

Mount the blocks vertically with a minimum of 2” between blocks. This air
gap is necessary to maintain proper cooling air flow through the block.

Maximum

Network Distance

Block

2.0 (50.8) air gap
on all 4 sides.

Operating temperature in

gap

below module must

air
not

exceed 60oC (140oF).

Figure 2.1
Mounting

Equipment
Grounding
Stud

CAUTION:

Dimensions for the Block I/O Modules (1791N4V2 shown)

2.710

1

(68.8)

1.71

(43.4)

ANALOG BLOCK

0

1

POWER

COMM

FAULT

1791N4V2

OUTPUT

INPUT

Inches

(Millimeters)

6.95H x 2.710W x 3.85D
(176.5H x 68.8W x 98D)

0

1

2

3

2 mounting holes
for 1/4inch screws

0.5

(12.7)

6.95

6.60

(176.5)

(167.6)

30

When tightening grounding stud nut, do not exceed 15 inlbs.

2-3

Chapter 2

Installing Block I/O

Connecting Wiring

Figure 2.2
Mounting

1. Hook top of slot over DIN rail.

2. While pressing block against rail,
pull down on locking lever.

3. When block is flush against rail,
push up on locking lever to
secure block to rail.

on a DIN Rail

Block

DIN Rail

AB pt. no. 199DR1

DIN 462773

EN 50022

(3.4 x 7.5mm)

Locking Lever

12382I

Make wiring connections to the removable terminal block which plugs into
the front of the block.

Figure 2.3
Removing

ATTENTION: The terminal block is not keyed to prevent
incorrect insertion. If you remove the terminal block, make
certain that it is inserted with the lower row of screws on the
outside of the block with number 1 at the top of the
terminal strip.

the T

erminal Block

To remove the terminal strip,
unscrew the two captive screws
and pull the terminal strip out.

2-4

12383I

Chapter 2

Installing Block I/O

Figure 2.4
Terminal

Block Pin Numbering

Refer to the following table for wiring schematics and connecting wiring
lists for the analog block modules.

Power Supply Voltage Input For Schematic refer to: For wiring refer to:

120V ac

24V dc

120V ac

24V dc

120V ac

24V dc

Wiring Connections for the Analog Block with

Wiring Connections for the Analog Block with
Voltage Inputs

Wiring Connections for the Analog Block with

Wiring Connections for the Analog Block with
Current Input and CustomerSupplied Loop Power

Wiring Connections for the Analog Block with

Wiring Connections for the Analog Block with
Current Input and BlockSupplied Loop Power

Figure 2.5, page 26 Table 2.B, page 29

Figure 2.6, page 26 Table 2.C, page 210

Figure 2.7, page 27 Table 2.D, page 211

Figure 2.8, page 27 Table 2.E, page 212

Figure 2.9, page 28 Table 2.D, page 211

Figure 2.10, page 28 Table 2.E, page 212

2-5

Chapter 2

Installing Block I/O

RIO

Figure 2.5

Connections for the 120V ac Analog Block with V

Wiring

GND

NOT

USED

BLU

CLR

RET
in0

GND
in0

RET
in1

GND
in1

RET
in2

GND
in2

RET
in3

GND
in3

RET
out0

RET
out1

NOT

USED

30

NOT

USED

SHD

in

in I0

in V1

in I1

in V2

in I2

in V3

in I3

+24
Vdc

out0

out1

1

L1

N

V0

L1

Voltage Input

+

User Analog
Input Device

-

User +24V User GND

Output

+

User Analog

Output Device

-

oltage Inputs

L2/N

Analog signals must be within the 10V
common mode voltage range which is
referenced to the analog input common
(GND). Typically, this is accomplished by
connecting to user ground. If an input
channel floats outside of this range,
invalid input readings will result.

RIO

Figure 2.6

Connections for the 24V dc Analog Block with V

Wiring

GND

NOT

USED

BLU

CLR

RET
in0

GND
in0

RET
in1

GND
in1

RET
in2

GND
in2

RET
in3

GND
in3

RET
out0

RET
out1

NOT

USED

30

RET
+24

NOT

USED

SHD

in

in I0

in V1

in I1

in V2

in I2

in V3

in I3

+24
Vdc

out0

out1

1

+24

V0

+

+24V dc

Supply

Voltage Input

+

User Analog
Input Device

-

User +24V User GND

Output

+

User Analog

Output Device

-

oltage Input

-

Analog signals must be within the 10V
common mode voltage range which is
referenced to the analog input common
(GND). Typically, this is accomplished by
connecting to user ground. If an input
channel floats outside of this range,
invalid input readings will result.

2-6