Allen-Bradley MicroLogix 1400 1766-L32AWAA 32-Point AC/Relay Controller with Analog I/O

Module Overview

The 1766-L32AWAA is a premium, all-in-one programmable logic controller within the MicroLogix 1400 family. Designed for sophisticated small-scale automation, this "AWAA" variant distinguishes itself by combining high-voltage AC discrete I/O with embedded 12-bit analog capabilities. It features a built-in LCD for real-time diagnostics and data manipulation, along with extensive communication options including EtherNet/IP. The 1766-L32AWAA is particularly effective for HVAC, water treatment, and standalone machine control where a mix of digital sensors, relay actuators, and analog process variables (like temperature or pressure) must be managed by a single, compact device.

Detailed Engineering Specifications

The 1766-L32AWAA serves as the central intelligence of the system, offering a rich set of embedded I/O that can be further expanded via 1762 series modules.

• Controller Type: MicroLogix 1400 (Base Unit)

• Power Supply: 110V to 240V AC (Operating range 100–240V AC @ 47–63 Hz)

• Digital Inputs: 20 Points (120V AC)

• Digital Outputs: 12 Points (Relay, Normally Open)

• Analog Inputs: 4 Channels (12-bit Voltage, 0–10V DC)

• Analog Outputs: 2 Channels (12-bit Voltage, 0–10V DC)

• User Memory: 20 KB (10 KB for user program / 10 KB for data)

• Data Logging/Recipe Storage: 128 KB for logging / 64 KB for recipes

• Communication Ports: * Port 0: 8-pin Mini DIN (RS-232/RS-485)

• Port 1: RJ45 (EtherNet/IP, DNP3 over IP, Modbus TCP/IP)

• Port 2: 9-pin D-Shell (Isolated RS-232)

• Expansion Capacity: Supports up to seven (7) 1762 MicroLogix expansion modules

• Operating Temperature: -20°C to 60°C (-4°F to 140°F)

• Physical Weight: 2.45 lbs (1.11 kg)

Advanced Interface and Connectivity

One of the defining features of the 1766-L32AWAA is the integrated backlit LCD. This interface allows maintenance personnel to monitor I/O status, change network configurations (such as IP addresses), and modify integer values without a laptop. For networked environments, its dual serial ports and dedicated Ethernet port support multi-protocol communication, enabling the controller to act as a bridge between legacy Modbus devices and modern SCADA systems via EtherNet/IP.

Integrated Analog Capabilities

Unlike the standard AWA model, the 1766-L32AWAA includes 4 voltage inputs and 2 voltage outputs directly on the base unit. These 12-bit channels provide sufficient resolution for typical industrial feedback loops, such as regulating the speed of a Variable Frequency Drive (VFD) via the 0–10V analog output or monitoring a level sensor on the input. Because these are built-in, they do not occupy expansion slots, leaving all seven expansion positions available for additional digital, specialty, or temperature modules.

Technical FAQ

Can the analog inputs on the 1766-L32AWAA be used for 4-20mA signals?

Natively, the embedded analog ports are designed for 0–10V DC. To use a 4-20mA sensor, you must place a high-precision 500-ohm resistor across the input terminals to convert the current to a 2–10V signal, or add a dedicated 1762-IF4 analog expansion module.

Does this AC-powered model support High-Speed Counters (HSC)?

No. High-speed counting (up to 100 kHz) is only available on MicroLogix 1400 models with 24V DC inputs. The 120V AC inputs on this model are intended for standard discrete logic and do not support high-frequency pulse detection.

How is the real-time clock (RTC) maintained during power loss?

The 1766-L32AWAA includes a replaceable lithium battery (1747-BA) that maintains the RTC and the volatile RAM memory for several years under normal conditions.