The Omron C200H-CPU21-E, also cataloged as the C200H-CPU21 Central Processing Unit, operates as a dedicated hardware component for program execution and I/O scanning within C200H rack-based PLC architecture.

Part Number Nomenclature & Configuration

• C200H: Modular rack-based PLC system family.
• CPU: Central Processing Unit processor module.
• 21: Standard feature set with dedicated START INPUT and RUN OUTPUT signals.
• E: International AC voltage supply rating (100 to 120 VAC / 200 to 240 VAC).

Technical Performance & Electrical Ratings

Backplane Synchronization & Density Management

The unit executes sequence instructions via cyclic, programmed, scheduled, and zero-cross refreshing across the rack assembly. Local backplane bus communication velocity dictates I/O refresh cycles across standard digital cards, special I/O modules, and CPU bus units. Firmware flash compatibility inside memory cassettes preserves system data structures, supporting predictable logic scan execution during multi-rack I/O density scaling.

Standard Module Shipping Package

• 1 x Omron C200H-CPU21-E Central Processing Unit
• 1 x Lithium Backup Battery Unit (Pre-installed or packaged)
• 1 x Protective Connector Cover Sheet

Field Wiring & Installation Rules

• Rack Alignment: Insert the CPU unit into the leftmost position on the C200H backplane until the upper and lower securing locks snap completely into place.
• Power Supply Wiring: Connect AC line power to the designated supply terminals using minimum AWG 16 copper conductors; wire a dedicated earth ground directly to the functional ground terminal.
• START INPUT Wiring: Route the 24 VDC external dry contact to the START INPUT terminals to govern RUN/STOP status execution via closed/open contact states.
• RUN OUTPUT Isolation: Keep the dry contact RUN OUTPUT wires isolated from high-frequency switching lines to reduce inductive noise backfeeding into the CPU board.

System Diagnostics FAQ

• How long can the backup battery maintain memory retention during a total AC power loss?

  The internal lithium battery retains RAM program and data memory for up to 4 years under ambient operating temperatures of 25 deg C.

• What operational window remains when the battery alarm indicator begins blinking?

  The backup battery must be replaced with a fresh cell within 1 week after the ALARM LED starts blinking on the front panel.

• Does the CPU unit support hot-swapping while installed on the backplane?

  No, removing or inserting the CPU module requires a complete AC power shutdown to avoid backplane connector damage and memory corruption.

• What memory areas remain intact during power failure without active AC line voltage?

  Holding Relay (HR) bits, Auxiliary Holding Relay (AR) bits, Counter (CNT) preset values, and Data Memory (DM) registers retain state via battery backup.

• What internal diagnostic routines are monitored continuously by the processor execution hardware?

  The CPU executes self-diagnostics for memory integrity, I/O bus communication, scan time timeouts, battery voltage, and CPU bus module states.

• What switching capacity limits apply to the dry contact RUN OUTPUT terminals?

  The output switch handles up to 2 A at 250 VAC for resistive loads, 0.5 A at 250 VAC for inductive loads, and 2 A at 24 VDC.

• Can an EEPROM memory cassette be utilized instead of a battery-backed RAM pack?

  Yes, EEPROM memory cassettes retain program and data memory without requiring constant lithium battery power for non-volatile storage.

• Which I/O control refresh methods are supported by the processing cycle logic?

  The processor manages field I/O through cyclic, programmed, scheduled, and zero-cross refreshing protocols across connected rack slots.