Rockwell Automation Allen-Bradley 1790D-N4CO User manual

CompactBlock LDX I/O Analog
Modules
Catalog Numbers 1790D-N4CO, 1790D-TN4CO, 1790D-TN4V0,
1790D-N0C2, 1790D-TN0C2, 1790D-TN0V2, 1790P-TN4C0,
1790P-TN0C2
User Manual Original Instructions

2Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
CompactBlock LDX I/O Analog Modules User Manual
Important User Information
Read this document and the documents listed in the additional resources section about installation, configuration, and
operation of this equipment before you install, configure, operate, or maintain this product. Users are required to familiarize
themselves with installation and wiring instructions in addition to requirements of all applicable codes, laws, and standards.
Activities including installation, adjustments, putting into service, use, assembly, disassembly, and maintenance are required to
be carried out by suitably trained personnel in accordance with applicable code of practice.
If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be
impaired.
In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use
or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and
requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for
actual use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software
described in this manual.
Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell Automation, Inc., is
prohibited.
Throughout this manual, when necessary, we use notes to make you aware of safety considerations.
Labels may also be on or inside the equipment to provide specific precautions.
WARNING: Identifies information about practices or circumstances that can cause an explosion in a hazardous environment,
which may lead to personal injury or death, property damage, or economic loss.
ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property
damage, or economic loss. Attentions help you identify a hazard, avoid a hazard, and recognize the consequence.
IMPORTANT Identifies information that is critical for successful application and understanding of the product.
SHOCK HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that dangerous
voltage may be present.
BURN HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that surfaces may
reach dangerous temperatures.
ARC FLASH HAZARD: Labels may be on or inside the equipment, for example, a motor control center, to alert people to
potential Arc Flash. Arc Flash will cause severe injury or death. Wear proper Personal Protective Equipment (PPE). Follow ALL
Regulatory requirements for safe work practices and for Personal Protective Equipment (PPE).

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 3
Table of Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
About This Publication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Who Should Use This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Download Firmware, AOP, EDS, and Other Files . . . . . . . . . . . . . . . . . . . . 7
Summary of Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 1
Overview How to Use Analog I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Hardware Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
General Diagnostic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
System Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Module Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Chapter 2
Installation and Wiring Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
General Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Reduce Noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Protect the Circuit Board from Contamination . . . . . . . . . . . . . . . . . 14
Install the CompactBlock LDX I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Set the Node Address on the Base Block. . . . . . . . . . . . . . . . . . . . . . . . 14
Mount the Base Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Mount the Optional Expansion Blocks . . . . . . . . . . . . . . . . . . . . . . . . . 15
Connect the DeviceNet Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
I/O System Wiring Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Input Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Output Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Effect of Transducer/Sensor and Cable Length Impedance on
Voltage Input Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Effect of Device and Cable Output Impedance on Output Module
Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Wiring the Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1790D-N4C0 Analog 4 Input Base D-shell Module Wiring . . . . . . . . 21
1790D-TN4C0, 1790D-TN4V0 Analog 4 Input Base Module Wiring 21
1790D-N0C2 Analog 2 Output Base D-shell Module Wiring . . . . . . 22
1790D-TN0C2, 1790D-TN0V2 Analog 4 Input Base Module Wiring 23
Chapter 3
Module Data, Status, and Channel
Configuration for Analog Input
Modules
Analog Input Image. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Analog Input Data File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Analog Input Data File With Discrete Input Expansion Module . . 26
Analog Input Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Table of Contents
Configure Analog Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Configure Analog Modules with RSNetWorx . . . . . . . . . . . . . . . . . . . . . . 29
Chapter 4
Module Data, Status, and Channel
Configuration for Analog Output
Modules
Analog Output Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Analog Output Data File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Analog Output Data File With Discrete Output Expansion Module .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Analog Output Data Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Output Fault and Idle States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Configure the Analog Output Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Configure Analog Modules with RSNetWorx . . . . . . . . . . . . . . . . . . . . . . 36
Chapter 5
Module Diagnostics and
Troubleshooting
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Status Indicator Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Activating Devices When Troubleshooting . . . . . . . . . . . . . . . . . . . . . 41
Stand Clear of the Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Program Alteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Safety Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Module Operation vs. Channel Operation . . . . . . . . . . . . . . . . . . . . . . . . . 42
Power-up Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Module Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Network Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Channel Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Out-of-Range Detection (Input Modules Only) . . . . . . . . . . . . . . . . . 43
Open-Circuit Detection (Input Module Only). . . . . . . . . . . . . . . . . . . 43
Analog Input Module Error Definition Table. . . . . . . . . . . . . . . . . . . . . . . 43
Module Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Channel Status Indicator Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Contacting Rockwell Automation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Appendix A
Install, Wire, and Configure
PROFIBUS Modules
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Module Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
General Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Reducing Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Protect the Circuit Board from Contamination . . . . . . . . . . . . . . . . . 48
Install the CompactBlock LDX I/O Block . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Set the Station Address on the Base Block . . . . . . . . . . . . . . . . . . . . . . 48
Mount the Base Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Connect the PROFIBUS DP Terminal Connector . . . . . . . . . . . . . . . 50
Connect Power to the Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Connect I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
General Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Guidelines for Input Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Guidelines for Output Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Wiring the Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 5
Table of Contents
1790P-TN4C0 Data Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Analog Input Image. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
1790P-TNOC2 Data Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Analog Output Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Output Fault and Idle States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Configuring PROFIBUS Analog Modules . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Configure Analog Modules with SST PROFIBUS Configuration Tool . 55
Download the Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Table of Contents
Notes:

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 7
Preface
About This Publication 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
Use this manual if you are responsible for designing, installing, programming,
or troubleshooting control systems that use CompactBlock™ LDX I/O modules.
Download Firmware, AOP,
EDS, and Other Files
Download firmware, associated files (such as AOP, EDS, and DTM), and access
product release notes from the Product Compatibility and Download Center at
rok.auto/pcdc.
Summary of Changes This publication contains the following new or updated information. This list
includes substantive updates only and is not intended to reflect all changes.
Additional Resources These documents contain additional information concerning related products
from Rockwell Automation.
You can view or download publications at rok.auto/literature.
Topic Page
Removed certification 13, 47
Updated template throughout
Updated language style throughout
Removed discontinued catalog numbers throughout
Resource Description
DeviceNet Analog Base Terminal Block CompactBlock LDX I/O Installation
Instructions, publication 1790-IN002 Provides detailed installation instructions for 1790D-TN4C0, 1790D-TN0C2, and 1790D-TN4V0
DeviceNet Analog Base D-shell CompactBlock LDX I/O Installation Instructions,
publication 1790-IN004 Provides detailed installation instructions for 1790D-N4C0, 1790D-N0C2
DeviceNet Media Design Installation Guide, publication DNET-UM072 Provides guidance on the required components of the cable system and how to design for
and install these required components.
System Security Design Guidelines Reference Manual, SECURE-RM001 Provides guidance on how to conduct security assessments, implement Rockwell
Automation products in a secure system, harden the control system, manage user access,
and dispose of equipment.
Industrial Components Preventive Maintenance, Enclosures, and Contact
Ratings Specifications, publication IC-TD002 Provides a quick reference tool for Allen-Bradley® industrial automation controls and
assemblies.
Safety Guidelines for the Application, Installation, and Maintenance of Solid-state
Control, publication SGI-1.1
Designed to harmonize with NEMA Standards Publication No. ICS 1.1-1987 and provides
general guidelines for the application, installation, and maintenance of solid-state control in
the form of individual devices or packaged assemblies incorporating solid-state
components.
Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1 Provides general guidelines for installing a Rockwell Automation industrial system.
Product Certifications website, rok.auto/certifications. Provides declarations of conformity, certificates, and other certification details.

8Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Notes:

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 9
Chapter 1
Overview
This chapter explains how analog data is used, and describes
CompactBlock LDX I/O analog input and output modules. Included is
information about:
• the use of analog I/O
• the module 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.
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.
Controller Analog I/O module
Valve
Level sensor
Analog input wired to tank
Analog output wired to valve

10 Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Chapter 1 Overview
The output module provides two single-ended analog output channels, either
voltage or current, depending on the module selected.
Table 1 lists the CompactBlock LDX I/O module types and corresponding
operating ranges:
Each analog base module supports up to two CompactBlock LDX I/O discrete
expansion modules.
Hardware Features
The modules contain either removable D-shell connectors or fixed terminal
blocks. The CompactBlock LDX I/O module four input channels are single-
ended. The CompactBlock LDX I/O module 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 shows the CompactBlock LDX I/O analog module hardware features.
Figure 1 - Hardware Features
General Diagnostic Features
The CompactBlock LDX I/O modules contain diagnostic features that can help
you identify the source of problems that may occur during power-up or during
Table 1 - CompactBlock LDX I/O Module Types and Operating Ranges
CompactBlock LDX I/O Module Type: Operating Range:
1790D-N4CO
1790D-TN4CO Current input 4…20 mA
or
0…20 mA
1790D-NOC2
1790D-TNOC2 Current output 0…20 mA
1790D-TN4VO Voltage input 0…10V DC
1790D-TNOV2 Voltage output 0…10V DC
DIN rail slot
DeviceNet
network
connector
Panel
mount
hole
Analog I/O
connections (D-
shell shown)
Panel mount hole
Node address switches
Expansion connector
under cover
Module
indicators

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 11
Chapter 1 Overview
normal channel operation. These power-up and channel diagnostics are
explained in Module Diagnostics and Troubleshooting on page 41.
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 I/O 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 indicator
remains off. If no faults are found during power-up diagnostics, the module
status indicator 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.
Module Operation
Input Module
The input module’s input circuitry consists of four analog inputs multiplexed
into one 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 2 shows a block diagram of the circuitry.
Figure 2 - Input Module Circuitry Block Diagram
Isolation
Signal
Control
Data
Microcontroller
Optocouplers
DeviceNetXCVR
Input 0
Select
24V DC
Field
Power
Analog
power
supply
Analog
power
A/D
Multiplexer
Input 1
Input 2
Input 3

12 Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Chapter 1 Overview
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 Module Data, Status, and Channel Configuration for
Analog Output Modules on page 33.
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 3 shows a block diagram of the circuitry.
Figure 3 - Output Module Circuitry Block Diagram
Isolation
Control
Data
Microcontroller
Optocouplers
DeviceNetXCVR
24V DC
Field
Power
Analog
power
supply
Analog
power
D/A
Analog
output
Analog
output
Output 1
Output 0

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 13
Chapter 2
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
Power Requirements The modules receive power through the DeviceNet network and from an
auxiliary 24V DC field supply. Table 2 shows the maximum power that the
modules draw.
General Considerations Reduce 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
reduces 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 that generate significant radiated heat.
In addition, route shielded, twisted-pair analog input and output wiring away
from any high-voltage I/O wiring.
Table 2 - CompactBlock LDX I/O Module Power Requirements
Voltage Range Power
DeviceNet Power 11…28.8 V DC 1.2 W @ 28.8V DC
Auxiliary 24V DC Field Power 21.6…26.4V DC 1.5 W @ 26.4V DC

14 Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Chapter 2 Installation and Wiring
Protect 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.
Install the 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 from 00 to 63.
The rotary switches are read at block power-up only. Switch settings from 64 to 99
cause the block to use the last valid node address stored internally.
Figure 4 - Node Address Settings
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 from 64 to 99.
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 The analog base module can accommodate a maximum of two
discrete expansion modules.
WARNING: 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.
NODE ADDRESS
MOD NET
STATUS
LSDMSD
Node Address is set to 11

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 15
Chapter 2 Installation and Wiring
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.
DIN Rail Mounting
1. Hook the top of slot of the block over the DIN Rail.
2. Pull down on the locking lever while pressing the block against the rail.
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 an 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 15 cm (5.90 in.) ribbon cable (1790-15CMCBL) and alternately
position the blocks in a right-side up, upside-down fashion.
You can mount your blocks on a panel or DIN rail as described in the previous
section.
CompactBlock LDX
1790-16BVOX
EXPANSION UNIT
16 INPUTS-DCPOWER
0707
Expansion
cover
95 mm
3.74 in
95 mm
3.74 in
Locking Lever

16 Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Chapter 2 Installation and Wiring
Figure 5 - Module Mounting
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 12 mm (0.47 in.) connector
with locking screws
Connect the DeviceNet wiring (drop line) to one of the DeviceNet connectors as shown
in Figure 6. A color-coded wiring diagram is also printed next to the connector on the
left side of the module.
Figure 6 - DeviceNet Wiring
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.
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.
EXPANSION UNIT CompactBlock LDX
PULL PULL
RIGHT SIDE UP
EXPANSION UNIT CompactBlock LDX
PULL PULL
RIGHT SIDE UP
EXPANSION UNIT CompactBlock LDX
PULL PULL
RIGHT SIDE UP
EXPANSION UNIT CompactBlock LDX
PULL PULL
RIGHT SIDE UP
EXPANSION UNIT CompactBlock LDX
PULL PULL
RIGHT SIDE UP
EXPANSION UNIT CompactBlock LDX
PULL PULL
UPSIDE DOWN
EXPANSION UNIT CompactBlock LDX
PULL PULL
RIGHT SIDE UP
The longer expansion cable
(1790-15CMCBL) will allow
up to 7cm of space in between
blocks.
Horizontal mounting
Vertical mounting
CompactBlock LDX
1790D-8BV8V
8 INPUTS/8OUTPUTS-DC POWER
0707
Vertical mounting
Wiring diagram for
1799-DNETCON
V+ Red
Can_H White
Drain/shield
Can_L Blue
V- Black
V+ Red
V- Black
Drain/shield
Can_H White
Can_L Blue
Wiring diagram for
1799-DNC5MMS

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 17
Chapter 2 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 permits.
• 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-TNOV2 modules are
referenced to COM. Load resistance for a voltage output channel must be
equal to or greater than 1 K.
• Current outputs (CH0 and CH1) of the 1790D-NOC2 and 1790D-TNOC2
modules source current that returns to COM. Load resistance for a
current output channel must remain between 0 and 600 .
Effect of Transducer/Sensor and Cable Length Impedance on Voltage
Input Accuracy
For voltage inputs, the length of the cable that is used between the transducer/
sensor and the module can affect the accuracy of the data that is provided by
the module.
(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 0.1 μF capacitor at the sensor end.

18 Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Chapter 2 Installation and Wiring
Figure 7 - Effect of Transducer/Sensor and Cable Length
Where:
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for 1790D-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.
For example, for Belden 8761 two conductor, shielded cable:
Rc = 16 /1000 ft
Rs = 0 (ideal source)
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, implement the following equation in the control program to
compensate for the added inaccuracy error due to the impedance of the source
and cable.
Table 3 - Effect of Cable Length on Input Accuracy
Length of Cable (m) DC Resistance of Cable, Rc () Accuracy Impact at Input Module
50 2.625 0.00105%
100 5.25 0.00210%
200 10.50 0.00420%
300 15.75 0.00630%
In a current loop system, source and cable impedance do not impact
system accuracy.
V in
Vs Ri
Rc
RcRs
+
-
Vin = [Ri x Vs]
[Rs + (2 x Rc) + Ri]
%Ai = Vin
Vs
()
1 - x 100
Vs = Vin x [Rs + (2 x Rc) + Ri]
Ri

Rockwell Automation Publication 1790-UM001B-EN-P - April 2021 19
Chapter 2 Installation and Wiring
Effect of Device and Cable Output Impedance on Output Module
Accuracy
The maximum value of the output impedance is shown in Figure 8, because it
creates the largest deviation from an ideal voltage source.
Figure 8 - Effect of Device and Cable Output Impedance
Where:
Rc = DC resistance of the cable (each conductor) depending on cable
length
Rs = Source impedance of 1790D-TNOV2 (0.5 )
Rload = Impedance of the load device
Vs = Voltage at the output of 1790D-TNOV2
Vload = Measured potential at the load device
%Ai = Percent added inaccuracy in a voltage-based system due to source
and cable impedance.
For example, for Belden 8761 two conductor, shielded cable and a
1790D-TNOV2 module:
Rc = 16 /1000 ft
Rs = 0.5 
Table 4 - Effect of Output Impedance and Cable Length on Accuracy
Length of Cable (m) DC resistance of the
cable, Rc ()
Accuracy impact at the load
1000 10,000 100,000 
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%
Ri
Rc
+
-
Rs Rc
Rc
Vs
+
–
Vload Rload
Vload = [Rload x Vs]
[Rs+ (2 x Rc) + Rload]
%AVload = (1 - ) x 100
Vs
Vload

20 Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Chapter 2 Installation and Wiring
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, implement the following equation in the control program to
compensate for the added inaccuracy error due to the impedance of the output
module and cable.
Wiring the Modules
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.
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 5.08 cm (2 in.) lengths. Strip about 5 mm (3/16
in.) 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.
Under normal conditions, this drain wire and shield junction must be
connected to earth ground, through 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 is present, ground the cable
shields to earth at the module and via a 0.1 μF 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.
In a current loop system, source and cable impedance do not impact
system accuracy.
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.
ATTENTION: Never connect a voltage or current source to an analog
output channel.
ATTENTION: Be careful when stripping wires. Wire fragments that fall
into a module could cause damage at power-up.
Vs= V load x [Rs+ (2 x Rc) + Rload
[Rload]
Cable
signal wire
signal wire
drain wire foil shield signal wire signal wire
Cut foil shield and drain wire