ProSoft 3100-MCM Modbus Communication Module for PLC-5

Product Description

Overview

The 3100-MCM is a Modbus Master/Slave communication module developed by ProSoft Technology for Allen-Bradley PLC-5 processors. It enables Rockwell Automation PLC systems to communicate directly with Modbus-compatible devices, including drives, analyzers, meters, and third-party control equipment.

Designed for legacy industrial environments, the 3100-MCM remains widely used in existing PLC-5 installations where Modbus RTU or ASCII connectivity is required without replacing the core control system.

Communication Functionality

The 3100-MCM operates as either a Modbus Master or Modbus Slave, allowing flexible network topologies. It supports both Modbus RTU and Modbus ASCII protocols, making it suitable for integration with a wide range of legacy and third-party devices.

In real-world applications, this module is commonly used to bridge Allen-Bradley PLC-5 controllers with Modbus field devices in process automation and utility systems.

Hardware Interface and Ports

The module features dual serial communication ports with DB-25 female connectors. These ports support RS-232, RS-422, and RS-485 electrical standards through configurable wiring, enabling point-to-point or multi-drop Modbus networks.

This flexibility allows engineers to adapt the 3100-MCM to different plant layouts without additional protocol converters.

System Integration

The 3100-MCM installs directly into a PLC-5 chassis slot and draws power from the PLC backplane. Configuration is performed through a combination of DIP switches and ProSoft configuration tools, offering precise control over baud rate, parity, node addressing, and protocol behavior.

From maintenance experience, once properly configured, the module provides stable long-term communication in continuous operation environments.

Technical Specifications

• Model: 3100-MCM

• Manufacturer: ProSoft Technology

• Compatible controllers: Allen-Bradley PLC-5

• Module type: Modbus communication interface

• Supported protocols: Modbus RTU, Modbus ASCII

• Operating modes: Master or Slave

• Communication ports: 2 × DB-25 female

• Electrical standards: RS-232, RS-422, RS-485

• Baud rate range: 300 to 19.2 kbps

• Data format: 8 data bits, selectable parity, 1 stop bit

• Maximum nodes: Up to 32 nodes per RS-485 segment

• Diagnostics: LED indicators for module and communication status

• Power supply: 5 V DC from PLC backplane

• Operating temperature: 0 °C to +60 °C

• Storage temperature: –40 °C to +85 °C

• Humidity: 5–95% non-condensing

• Lifecycle status: Discontinued / legacy product