The Allen-Bradley MicroLogix 1400 (1766-L32BXB) is a high-performance, versatile compact PLC designed for small to mid-sized industrial applications. It is often considered the "Swiss Army Knife" of the MicroLogix family because it bridges the gap between simple micro-controllers and high-end modular systems like CompactLogix.
The L32BXB version is a "hybrid" model, combining fast DC inputs, high-speed counting, and a mix of relay and FET outputs.
The model number identifies the specific power and I/O hardware:
1766: Bulletin number for MicroLogix 1400.
L32: Total of 32 integrated I/O points.
B: 24V DC Input Power.
X: 24V DC Digital Inputs (Sink/Source).
B: A combination of Relay and 24V DC FET outputs.
| Feature | Details |
| Digital Inputs | 20 total (12 Fast 24V DC, 8 Standard 24V DC) |
| Digital Outputs | 12 total (6 Relay, 3 Fast DC FET, 3 Standard DC FET) |
| Analog I/O | None integrated (Requires 1762 expansion modules) |
| Program Memory | 20 KB (Approx. 10,000 steps) |
| Data Memory | 12 KB |
| High-Speed Counters | 6 channels (up to 100 kHz) |
| Pulse Train Outputs | 3 channels (up to 100 kHz) |
One of the 1400's greatest strengths is having three simultaneous communication ports:
Ethernet/IP (RJ45): Supports messaging, DNP3 over IP, and web server capabilities.
RS-232 (9-pin D-sub): Isolated port for HMIs, modems, or DF1/Modbus RTU.
RS-485 (8-pin Mini-DIN): Non-isolated port for daisy-chaining multiple devices (DH-485 or Modbus).
Backlit LCD Screen: Allows you to monitor I/O status, view/edit data table values, and change the IP address or communication settings without a computer.
Online Editing: Unlike the smaller MicroLogix 1100, the 1400 allows you to modify the program while the machine is running (Online Edits).
Expansion: It can support up to seven 1762 expansion modules, allowing you to add specialized Analog, Thermocouple, or high-density Digital I/O.
Real-Time Clock: Built-in for time-stamping events or scheduling operations.