Selection Guide · Publication 1492-SG121 · Rockwell Automation

1492 I/O Wiring Conversion Systems: 1771 to 1756 I/O

This selection guide covers the 1492 I/O Wiring Conversion System for migrating Allen-Bradley 1771 PLC-5 I/O to 1756 ControlLogix I/O. It provides product selection tables for conversion modules, pre-wired cables, and conversion mounting assemblies for digital inputs, digital outputs, analog inputs and outputs, and 1771-N High Resolution Isolated Analog I/O modules. Wiring diagrams for each conversion path are included along with chassis dimension data and module specifications. Engineers planning a PLC-5 to ControlLogix migration use this guide to select compatible catalog numbers without removing existing field wiring from swing arms.

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10.25 in. Combined Assembly Depth
0...+60 Operating Temperature
16 Max Conversion Module Slots (largest assembly)
July 2016 Publication Date

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Specifications

Specifications

Dimensions (H x D x W) 300 x 111.25 x 38.1 mm (11.81 x 4.38 x 1.5 in.)
Approximate Shipping Weight 260 g (0.57 lb)
Storage Temperature -40...+85 °C (-40...+185 °F)
Operating Temperature 0...+60 °C (+32...+140 °F)
Operating Humidity 5...95% at +55 °C (+131 °F)
Shock (Nonoperating) 50 g
Shock (Operating) 30 g
Operational Vibration 2 g at 10...500 Hz
Pollution Degree 2
Environmental Rating IP20

Conversion Mounting Assembly Chassis Compatibility

1771-A1B (4 slots): assembly 1492-MUA1B-A4-A7, 4 conversion module slots, 9.01 in. (229 mm) wide
1771-A2B (8 slots): assembly 1492-MUA2B-A7-A10, 8 conversion module slots, 14.01 in. (356 mm) wide
1771-A3B1 (12 slots): assembly 1492-MUA3B-A10-A13, 12 conversion module slots, 19.01 in. (483 mm) wide
1771-A4B (16 slots): assembly 1492-MUA4-A13-A17, 16 conversion module slots, 24.01 in. (610 mm) wide

Catalog Number Format

How to read an Allen-Bradley 1492 catalog number. Each position encodes a specific configuration attribute.

Position
Meaning
Example
Conversion module
1492-CM1771: Bulletin 1492 conversion module that accepts the existing 1771 swing arm
1492-CM1771-LD001
Cable length digits
The 005 in the catalog number indicates the cable length; 0.5 M is the recommended length listed, 1.0 M (010) is also available
1492-CONCAB005X, 1492-CONCAB010_
Dual cable assembly
1492-C followed by two length codes: 0.5M/0.5M (C005005), 1.0M/1.0M (C010010), 0.5M/1.0M (C005010), 1.0M/0.5M (C010005)
1492-C005005XE

Certifications & Compliance

UL Classified (UL File No. E113724) CE: compliant for all applicable directives

Document Contents

Full PDF covers the following topics in detail:

  • Conversion Modules, Cables, and Mounting Assemblies
  • Conversion Mounting Assembly Selection
  • Chassis Dimensions and Max Slot Information
  • Digital Inputs
  • Digital Outputs
  • Analog Inputs and Outputs
  • 1771-N High Resolution Analog I/O Modules
  • Specifications
  • Wiring Diagrams

Frequently Asked Questions

How does the 1492 I/O Conversion System avoid removing existing field wiring?
The existing 1771 swing arms fit directly onto the edge connector of the 1492 conversion modules. I/O signals are routed through the conversion module and a pre-wired cable to the appropriate terminals on the new 1756 I/O module, so no field wires need to be removed from the swing arm.
What three components make up the 1492 I/O Conversion System?
The system consists of Conversion Modules (e.g., 1492-CM1771-LD001), pre-wired Cables (e.g., 1492-CONCAB005X), and a Conversion Mounting Assembly (e.g., 1492-MUA4-A13-A17).
How do I select the correct Conversion Mounting Assembly?
First, determine the quantity and type of 1771 I/O modules in the chassis. Then use the chassis dimension table to match the 1771 chassis catalog number to the corresponding 1492 Conversion Mounting Assembly, ensuring the assembly has enough conversion module slots. Note that two conversion module slots are required when two 1771 modules convert to one 1756 module, and two 1756 chassis slots are required when one 1771 module converts to two 1756 modules.
What is the combined depth of the conversion mounting assembly with a 1756 chassis mounted on top?
The combined depth is 10.25 inches with a controller with key, or 10.0 inches with a controller without key.
Can the 1756 chassis be positioned in different locations on the Cover Plate?
Yes. The Conversion Mounting Assembly Cover Plate has pre-drilled and tapped mounting holes that allow the 1756 chassis to be mounted centered, right-justified, or left-justified without drilling new holes in the control cabinet.
How is the 1771-N High Resolution Isolated Analog I/O converted without removing field wires?
The two existing 1771 cables connecting the 1771-N modules to the 1771-RTPs (Remote Termination Panels) are replaced with two 1492-CONACAB020 series cables. Each replacement cable connects directly to the existing 1771-RTP on one end and to a 1756 RTB on the other end, so no field wires are disturbed.
What cable lengths are available for 1492 conversion cables?
For single cables, 0.5 M (005) and 1.0 M (010) lengths are available. For dual cable assemblies, options include 0.5 M/0.5 M (1492-C005005X_), 1.0 M/1.0 M (1492-C010010X_), 0.5 M/1.0 M (1492-C005010X_), and 1.0 M/0.5 M (1492-C010005X_).

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