Description
Key Technical Specifications
- Model Number: PC-E984-685
- Manufacturer: Schneider Electric (Modicon / AEG)
- Product Type: Programmable Logic Controller (PLC) CPU
- Series: Modicon 984 Series
- Processor: 16-bit CPU
- User Logic Size: 16K Words
- Logic Solve Time: 1.0 ms per 1K words
- RAM State Registers: 4096 Registers
- Max System I/O: 16,384 Discrete I/O points
- Communication Ports: 2x Modbus, 1x Modbus Plus
- Power Supply: 115/230V AC, 50/60Hz
- Installation: Slot-mounted backplane
Functional Role & Application Analysis
The Schneider PC-E984-685 is a classic, heavy-duty programmable logic controller from the legendary Modicon 984 series. It solves the critical need for reliable, deterministic logic control in legacy manufacturing environments. Built around a 16-bit processor with 16K words of user memory, this CPU handles complex interlocking, sequencing, and motor control tasks with absolute predictability. Its integrated Modbus and Modbus Plus ports allow it to communicate seamlessly with older HMIs, SCADA systems, and distributed I/O racks.
Typical use cases include:
- Legacy Manufacturing Lines: Keeping decades-old automotive, paper, or steel mill machinery running by replacing a dead 984 CPU without rewriting the control logic.
- Water & Wastewater Infrastructure: Managing pump station sequencing and valve control in municipal facilities where the original 984 logic has run flawlessly for years.
- Process Control: Executing batch processes and safety interlocks in chemical or food processing plants using the original ProWorx 32 or Concept programming environments.
Our Quality Standard & Testing Process
We understand that the cost of an unreliable part is far greater than its purchase price. A failed CPU means a stopped line and a desperate search for a legacy spare. We have established a rigorous, multi-stage testing process to ensure every product we ship is 100% functional and meets original OEM tolerances.
- Visual & Component Inspection: We inspect the backplane connectors, power supply components, and PCB traces for thermal damage, capacitor leakage, or oxidation.
- Live System Test: The CPU is installed in a live 984 test rack. We run a 24-hour burn-in, verifying power-up stability, memory retention, and thermal performance.
- Full-Function Diagnostics: We load a test logic program to verify the 1.0 ms/1K solve time, test all Modbus/Modbus Plus communication ports, and validate RAM state registers.
- Warranty Backing: Only parts that pass all diagnostic tests are approved for shipment and backed by our full 12-month warranty.
SCHNEIDER PC-E984-685
Compatibility & Migration Paths
To ensure this PC-E984-685 is 100% compatible with your system, you must check these key compatibility points. Failure to verify this is a common project risk. Legacy 984 systems are highly configuration-dependent.
- Logic Size Match: Confirm your existing program does not exceed the 16K word limit. If your program is larger, you may need a different 984 CPU variant.
- Software Compatibility: Verify your programming software. This CPU is typically programmed using ProWorx 32 or Concept. Ensure your project file is compatible before swapping the hardware.
- Loadable Files: If your system uses specific A120 I/O modules, you may need to download specific loadable files (e.g., Dsc1.dat) to prevent Error Code 4000 on startup.
- Get Expert Help: Unsure about your logic size or software version? Contact our technical team today for a free compatibility check. Send us a photo of your CPU nameplate and a copy of your program file.
