Product Details:

MODICON D984-385, also widely known as 984 385D, is the core CPU processor module for the classic Modicon 984 PLC platform originally released by AEG Modicon. As the central brain of the whole control system, it executes ladder logic programs, scans local and remote I/O points, runs closed-loop control algorithms and handles data exchange with upper monitoring equipment and operator panels. This processor carries 16K words of program memory and 2K words of RAM for process variables, supporting up to 512 discrete I/O points to satisfy medium-scale automation control demands. It provides both Modbus and Modbus Plus communication interfaces for connecting HMI, remote RIO racks and other intelligent automation devices. It adopts standard rack mounting design for installation on Modicon 984 backplane, equipped with multiple LED indicators to display power, run status, communication activity and low battery alarm. Built with industrial-grade components and EMC suppression circuits, it can sustain continuous long-cycle operation under heavy electromagnetic interference in factory workshops. As an obsolete original spare part, it is mainly used for maintenance and retrofit of aging Modicon 984 control systems. Direct replacement retains the original logic program, wiring layout and network architecture, avoiding large-scale system transformation and cutting production downtime.

Basic Parameters

Product type: Modicon 984 series CPU processor module

Program memory: 16K words

User RAM: 2K words

Max discrete I/O: 512 points

Installation: rack mount for Modicon 984 backplane

Communication: Modbus, Modbus Plus

Operating temperature: 0°C ~ +60°C

Protection grade: IP20

Supported Functions

Ladder logic program scanning and execution

Local and remote I/O data collection and output

PID closed-loop regulation

Modbus and Modbus Plus data transmission

Program upload and download

Battery-backed memory retention

Core Functions

Real-time logic calculation and sequence control

Onboard multi-status LED indication

Communication frame parsing and forwarding

Fault and diagnostic code storage

Remote programming access

Watchdog protection for program runaway

Hardware Specifications & Environmental Features

Built-in surge and noise 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Status: Obsolete original part, available for spare replacement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 chemical process control, old paper making production lines, conventional power plant auxiliary control and large material handling automation racks.

Note: Confirm backplane compatibility, program memory requirement and communication cable type before ordering.

This is from our current stock.

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