Description
Schneider PC-E984-685
Technical Specifications: Product type: Modicon 984 rack-based PLC CPU module User program memory: 16K logic memory Data memory: Internal RAM for register and flag storage Backplane interface: Modicon 984 proprietary rack backplane bus Communication ports: Modbus Plus port, RS232 programming port Power supply: Powered by rack backplane Operating temperature range: 0℃ ~ +60℃ Storage temperature range: -40℃ ~ +85℃ Relative humidity: 5% to 95%, non-condensing Mounting form: Plug-in single slot rack module Protection grade: IP20 when installed inside control cabinet
Functional Features: Execute Modicon 984 ladder logic user control program with cyclic scan mode. Communicate with rack-mounted local I/O modules via backplane bus. Modbus Plus peer-to-peer industrial network communication function. RS232 port for local programming, upload and download of user program. Battery-backed RAM to retain program and register data during power loss. Hardware watchdog timer to detect CPU program runaway and trigger fault state. Front panel LED indicators for power, run status, fault and communication activity. Support remote I/O drop connection over Modbus Plus network. Power-on self-test for memory and internal circuit integrity check.
Application Scenarios: Legacy petrochemical plant control system, old power plant auxiliary control, water treatment retrofitted control cabinets, traditional manufacturing production line control, pulp and paper mill old automation systems, mining plant legacy PLC control.
Performance Parameters: Stable cyclic program scanning within designed memory capacity limit. Battery backup retains data registers and user program after power interruption. Modbus Plus network supports peer-to-peer data exchange between multiple 984 CPUs. 24-hour continuous operation inside temperature-controlled industrial control cabinet. Hardware watchdog provides protection against program execution failure.
Material Composition: PCB substrate: Multi-layer FR4 glass fiber epoxy printed circuit board with conformal coating. Core components: 16-bit microprocessor, program RAM, non-volatile memory, Modbus Plus communication transceiver, watchdog timer chip. Front panel: Black flame retardant ABS plastic panel with silk screen and LED transparent windows. Backplane connector: Gold plated copper alloy contact pins. Battery compartment: Built-in holder for lithium backup battery.
Structural Features: Single width plug-in rack card structure for Modicon 984 chassis. Front panel equipped with multi-color LED status indicators. Front side Modbus Plus and RS232 D-SUB connectors. Rear edge gold plated backplane connector inserting into rack backplane slot. Internal circuit separated into CPU processing area, memory area and communication transceiver area. Built-in lithium battery holder for RAM data backup. Mechanical locking latch to secure module inside rack slot.
Working Principle: CPU module receives power supply from rack backplane. After power-on self-test completes, the processor loads ladder logic program stored in battery-backed RAM and starts cyclic scan cycle. The CPU reads input status from I/O modules via backplane bus, executes ladder logic instructions, calculates output states and writes output values to I/O modules. Modbus Plus transceiver handles peer-to-peer data exchange with other Modbus Plus nodes. RS232 port communicates with programming terminal for program upload and download. Hardware watchdog continuously monitors program execution; if program execution stops, watchdog triggers fault state and stops output operation. Front panel LEDs display operating and fault status.
Installation Requirements: Cut off PLC rack power supply before inserting or removing PC-E984-685 module. Insert module into designated slot of Modicon 984 rack and fasten front latch. Connect Modbus Plus network cable and RS232 programming cable to front connectors. Install programming software on dedicated programming terminal. Upload existing program or download new ladder logic project. Install lithium backup battery into battery compartment. Ensure control cabinet protective earth connection is reliable. Reserve ventilation space around rack modules for heat dissipation.
Usage Notes: Backup user program before module removal or battery replacement. Replace lithium backup battery within specified service interval to prevent data loss. Wear anti-static wristband during module handling. Do not hot swap module when rack is energized. Regularly inspect front panel LED indicators and connector tightness. Do not operate module outside rated temperature and humidity range. Prevent dust accumulation on backplane connector pins.
