Schneider Electric PC-0984-381 Modicon 984-381 Controller Module

The Schneider Electric PC-0984-381 (also designated as the Modicon 984-381) is a single-slot central processing unit and power supply main module engineered for the Modicon 984 programmable controller platform. It integrates a 16-bit processor, user memory storage, and a dual-voltage primary power supply within a single metal-clad module. Designed for medium-to-large machine control and process automation, it executes ladder logic routines while supplying operating power and communication management to Modicon 800 Series I/O racks.

Processor Capability and Extended Memory Structure

The PC-0984-381 features an expanded memory architecture compared to standard 984-380 variants. It provides 16K words of user logic memory paired with 2K words (2,048 registers) of state RAM to accommodate larger control programs, complex arithmetic functions, and data logging requirements.

Operating on a 16-bit processor architecture, the CPU maintains a logic solve speed of 5 ms per 1,000 nodes. Program protection is enforced via a physical front-panel memory lock switch, while dynamic state RAM and user logic are preserved during power loss by an internal lithium battery that provides up to 14 days of backup retention after low-battery detection.

Integrated Power Supply and Interface Configuration

The onboard primary power supply accepts wide AC utility inputs, operating at 120/220 VAC nominal (47–63 Hz) at 0.5 A / 0.25 A. Front-panel diagnostic LEDs display real-time status indicators for AC power, CPU execution mode, memory battery health, and communication link activity.

Equipped with a standard Modbus serial port, the module plugs directly into Modicon 800 Series chassis housing, driving local I/O drops and interfacing with remote I/O networks or operator interfaces.

Technical Specifications

Frequently Asked Questions

Q: What is the primary difference between the Modicon PC-0984-381 and the PC-0984-380?

A: The PC-0984-381 offers expanded memory capacity, providing 16K words of user logic memory compared to the 8K/6K word limit on the PC-0984-380 model, making it suitable for larger automation programs.

Q: What electrical supply limits does the integrated power supply require?

A: The onboard power supply operates on standard AC utility lines rated for 120 to 220 VAC at 50/60 Hz (47–63 Hz line frequency range), drawing 0.5 A at 120 VAC or 0.25 A at 220 VAC.