Allen Bradley 1766-L32BWA PLC with Mixed Digital Inputs and Multiple Communication Ports

Product Overview

The Allen-Bradley 1766-L32BWA is a robust programmable logic controller (PLC) in the MicroLogix 1400 family from Rockwell Automation. It is designed for machine-level control and smaller process automation tasks, offering a balance of performance, expandability, and communications flexibility. It is especially suitable for users who need AC power input, relay outputs, a mix of fast and normal digital inputs, and multiple communication ports (including Ethernet) with support for various industrial protocols.

This model is often chosen for applications such as packaging machines, conveyors, material handling, batch systems, and other discrete control systems, including those requiring high-speed input counting or data logging. Its built-in LCD display, real-time clock, and support for up to seven expansion modules make it versatile, enabling system designers to scale or adapt as needed.

Key Features & Benefits

• Mixed Digital Inputs: Offers both fast digital inputs and standard digital inputs. Fast inputs can be used for high-speed events such as counting, pulse monitoring etc.

• Relay Outputs: Twelve (12) relay outputs allow switching of AC loads and provide good isolation from control electronics.

• Multiple Communication Ports:

  • An isolated RS-232/RS-485 combo port;

  • A non-isolated RS-232 port;

  • And an Ethernet port (10/100 Mbps) for EtherNet/IP, Modbus TCP/IP, DNP3 over IP, etc. This enables integration into modern networked automation systems, remote monitoring, or mixing with legacy serial devices.

• Built-in Real-Time Clock (RTC) and LCD Display: Provides local status viewing, configuration without additional equipment, and supports operations like recipe/data monitoring/manipulation directly.

• Expandability: Supports up to 7 local expansion I/O modules (Bulletin 1762), enabling increased I/O point counts as system complexity grows.

• Wide Power Input Range: Operates from 100-240 VAC, making it compatible with many industrial power systems globally.

• Flexibility in Protocol Support: DF1, DH-485, Modbus RTU, ASCII, DNP3 (serial and over Ethernet), EtherNet/IP messaging – ensures interoperability with a broad set of equipment.

• High Reliability and Ruggedness: Designed for industrial environments: wide operating temperature, vibration, shock, etc. Built per Rockwell Automation standards for IEC and UL etc.

Use Cases

Here are some typical scenarios where the 1766-L32BWA shines:

• A factory needing to retrofit or upgrade older systems but still maintain support for serial protocols (RS-232, RS-485), while also integrating Ethernet based devices or SCADA.

• Machines or assembly lines requiring high-speed input detection (e.g. counting parts or shaft encoders) along with standard discrete sensing.

• Situations where process control requires time-based events or recipes, thus benefitting from the real-time clock and data logging.

• Environments with varying AC power supply (110-240V), where the wide input range is an advantage.

• Cases where the operator or maintenance personnel need local visibility via LCD without constantly using a PC or HMI.

Technical Specifications (Table)

Considerations & Limitations

• No Analog Inputs/Outputs in this Version: If your application requires analog control or measurement (e.g. 4-20mA inputs, voltage outputs etc.), you will need either a different variant (with analog I/O) or external modules.

• Relay Outputs vs Solid-State Outputs: Relay outputs provide good isolation and ability to switch AC loads, but have slower switching speed and mechanical wear. For high-frequency switching or long life under frequent operation, solid-state or transistor/FET outputs may be preferable.

• Open Enclosure: The unit is not sealed/enclosed for harsh environments; dust, moisture, or corrosive atmospheres may require additional protection or an enclosure.

• Expansion Module Wiring & Provisioning: Adding expansion I/O adds wiring, layout challenges, and may affect mounting space. Also, expansion bus power and current requirements must be observed (per series revision).

• Firmware / Series Revisions: As with many PLC products, different hardware revisions (“Series A”, “Series B”, “Series C”) might have small differences. It’s important to ensure the firmware and hardware revision suits your software tools and any spare parts / modules compatibility. 

• Power Inrush: The AC power input has significant inrush current: per specifications, about 25 A for 8 ms at 120V AC, and 40 A for 4 ms at 240V AC. Proper supply wiring and protection (fusing, circuit breaker, etc.) necessary.

Summary

The Allen-Bradley 1766-L32BWA is a solid choice when you need a PLC that provides:

• AC power compatibility (100-240 VAC),

• A decent number of digital I/O including high-speed inputs,

• Relay outputs for AC switching,

• Multiple communications including Ethernet + serial, and

• Expandability for future growth.

It is particularly effective for mid-level industrial controls, retrofit situations, mixed legacy/new systems, or where local visualization (LCD) is helpful. It offers strong reliability and is backed by Rockwell Automation’s documentation, standards, and support.