Product Details:

MODICON PC-E984-685 is a classic rack-mounted CPU processor belonging to the Modicon 984 controller family, originally developed by Gould Modicon. It serves as the core processing unit for the whole automation rack, responsible for executing ladder logic programs, scanning local and remote I/O, handling arithmetic operations, interlock control and closed-loop process regulation. This processor carries dual built-in Modbus serial ports for simultaneous connection to programming terminals, HMI panels and host SCADA systems, and supports optional S908 remote I/O bus expansion to build distributed I/O architectures. It adopts standard backplane rack installation and works with matched power supply, local I/O and remote racks. Front panel LED indicators display run status, communication activity and fault alarms for quick field inspection and troubleshooting. Industrial-grade circuit design with built-in surge suppression and EMC filtering ensures stable continuous operation under heavy electromagnetic interference on factory floors. It relies on backup battery to retain user logic and register data after power loss. As an obsolete original spare part, it is used for maintenance and retrofit of legacy Modicon 984 automation systems. Direct drop-in replacement keeps the existing control program, remote I/O layout and serial communication configuration unchanged, avoiding large-scale system reconstruction and cutting production downtime.

Basic Parameters

Product type: Modicon 984 series main CPU programmable controller

Programming software: Modsoft

Communication: dual Modbus RS232 serial ports, optional S908 RIO

Max I/O capacity: up to 2048 combined local and remote I/O

Installation: rack mount for Modicon 984 dedicated backplane

Memory: onboard user logic memory with battery backup

Operating temperature: 0°C ~ +60°C

Protection grade: IP20

Supported Functions

Ladder logic program scanning and execution

Local and remote I/O data acquisition and output

Dual-channel Modbus RTU communication

S908 remote I/O bus management

Program upload, download and online monitoring

Battery-backed retention of register and program data

Core Functions

Real-time logic solving and sequence control

Onboard multi-status LED indication for run and fault

Serial port transient surge suppression

Modbus master and slave communication

Data frame verification and retransmission

Diagnostic flag storage for processor and bus faults

Hardware Specifications & Environmental Features

Built-in noise filtering and surge suppression circuit

Storage temperature: -25°C ~ +70°C

Relative humidity: 5% to 95% non-condensing

Status: Obsolete original part, available for spare replacement

Industry Applications:Applied in legacy petrochemical distributed control, old paper making production automation, water treatment remote signal collection and large conveyor remote I/O control racks.

Note:Confirm backplane compatibility, battery condition and Modbus wiring definition before ordering.

This is from our current stock.

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