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Industrial Automation & Network Hardware
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Hardware Comparison: MicroLogix 1400 Selection Guide

May 06, 2025

As the de facto standard for industrial programmable logic controllers, Rockwell Automation’s line of Allen-Bradley PLCs covers the full spectrum of application scales, from hobbyist to multi-site systems. In this article, we’ll examine one of the most popular and cost-effective PLC options in Allen-Bradley’s catalog: the MicroLogix 1400 family.

MicroLogix Family Overview

The MicroLogix series sits at the micro-scale end of Allen-Bradley’s PLC offerings, just under small-scale options such as the CompactLogix series, and farther yet under large-scale solutions including the flagship ControlLogix series. These groupings simply indicate the scale of applications each family is built to serve.

The Allen-Bradley MicroLogix family of PLCs is based on two paramount features: compact size and cost-effectiveness. Here is a quick breakdown of the product families:

Bulletin # Series Name Description
1761 MicroLogix 1000 Ultra-compact, low cost, fixed I/O points
1763 MicroLogix 1100 Adds onboard LCD, embedded analog, and Ethernet
1762 MicroLogix 1200 Small size, scalable, expandable
1766 MicroLogix 1400 Adds high-speed counter, pulse train, and expandability
1764 MicroLogix 1500 Modular, highly expandable design

We’ll focus on the MicroLogix 1400, also known under Bulletin 1766. This product line incorporates the most advanced features of the MicroLogix family.

MicroLogix 1400 Overview

All MicroLogix 1400 PLCs offer:

  • 20 digital inputs

  • 12 digital outputs

  • Expandability for up to 7 x 1762 I/O modules (up to 256 digital I/O)

  • Online editing

  • 10k word user program and data memory

  • 128k bytes for data logging and 64k bytes for recipe storage

  • Dual serial ports: DF1/DH485/Modbus RTU/DNP3/ASCII

  • Built-in Ethernet/IP, web server, and email functions

  • Onboard LCD screen

These PLCs are frequently used in multi-tank batching, pump systems, multi-axis machine control, and small pilot plants. Their affordability and power make them an ideal bridge between entry-level and mid-range controllers.

 
Standard MicroLogix 1400 Models
Catalog Number Description
1766-L32AWA 20 x 120V AC Inputs, 12 Relay Outputs, 110/240V AC Power
1766-L32AWAA Above plus 4 Analog Inputs, 2 Analog Outputs
1766-L32BWA 12 Fast + 8 Normal 24V DC Inputs, 12 Relay Outputs, 110/240V AC Power
1766-L32BWAA Above plus 4 Analog Inputs, 2 Analog Outputs
1766-L32BXB Same input split, 6 Relay + 6 FET Outputs, 24V DC Power
1766-L32BXBA Above plus 4 Analog Inputs, 2 Analog Outputs

These six configurations differ in input type (AC vs. DC), analog I/O presence, output type (Relay vs. FET), and power supply.

I/O Comparison Chart
Catalog Number Line Voltage Digital Inputs Digital Outputs Analog I/O
1766-L32AWA 120/240V AC 20 x 120V AC 12 Relay None
1766-L32AWAA 120/240V AC 20 x 120V AC 12 Relay 4 In, 2 Out
1766-L32BWA 120/240V AC 12 Fast + 8 Normal 24V DC 12 Relay None
1766-L32BWAA 120/240V AC 12 Fast + 8 Normal 24V DC 12 Relay 4 In, 2 Out
1766-L32BXB 24V DC 12 Fast + 8 Normal 24V DC 6 Relay, 3 Fast FET, 3 Normal FET None
1766-L32BXBA 24V DC 12 Fast + 8 Normal 24V DC 6 Relay, 3 Fast FET, 3 Normal FET 4 In, 2 Out
 
Application Recommendations

  • Basic Relay Control: Use 1766-L32AWA or L32BWA depending on input type (AC vs DC).

  • Sensor-Driven Process Monitoring: Choose L32AWAA or L32BWAA with analog I/O.

  • Fast Switching & DC Control: Select L32BXB or L32BXBA with FET outputs.

Expandability & Accessories

All MicroLogix 1400 PLCs support expansion via Bulletin 1762 I/O modules, including:

  • 1762-IA8: 120V AC input

  • 1762-IB16: 24V DC input

  • 1762-OW8: Relay output

  • 1762-OB16: DC output

  • 1762-IF2OF2: Analog I/O

  • 1762-IR4/IT4: RTD & Thermocouple modules

Additionally, the 1766-MM1 memory module allows backup and transfer of programs between units.

Conclusion

The MicroLogix 1400 series offers a robust, flexible PLC option for machine builders, OEMs, and facility engineers seeking cost-effective, scalable solutions. Its onboard features and I/O expandability make it a standout choice before stepping up to mid-tier platforms like CompactLogix.

For assistance selecting the right PLC for your application, contact PLG Automation at sales@plgautomation.com or 800-906-9271.