The Omron CQM1H-CPU21, also cataloged as the CQM1H-CPU21 CPU Processor, operates as a dedicated hardware component for central logic execution and I/O scanning within SYSMAC CQM1H PLC racks.

Processor Model Architecture

• CQM1H Series Base: Standard programmable logic controller architecture for modular rack configurations.
• CPU Class Identifier: Central processing unit managing instruction execution and system backplane timing.
• 21 Functional Level: Built-in 16 DC inputs, integrated RS-232C serial interface port, and support for inner board slot expansions.

System Specifications

Deterministic Network Routing and Firmware Execution

The CQM1H-CPU21 maintains precise backplane bus communication velocity across local I/O modules and inner board expansion cards. High firmware flash compatibility ensures real-time program execution without cycle timing jitter. Direct memory mapping links onboard 24 VDC inputs to CPU registers with deterministic scan intervals, maintaining I/O density scaling throughout complex control operations.

Package Fulfillment List

• 1 x Omron CQM1H-CPU21 CPU Processor Unit
• 1 x RS-232C Port Dust Cover Plug
• 1 x Terminal Block Connector Assembly

Rack Installation and Wiring Rules

• Power Off Assembly: Always disconnect main power from the rack power supply unit prior to mounting or detaching the CPU module.
• Grounding Connection: Ensure the functional ground terminal on the rack assembly connects directly to protective earth to avoid ground loops.
• Cable Separation: Route RS-232C communication and 24 VDC signal wiring away from high-voltage motor circuits and power conduits.
• Module Latching: Verify top and bottom rack retention locks engage fully into adjacent expansion units to secure internal bus contacts.

Technical Questions and Answers

• Does the CQM1H-CPU21 CPU processor support hot-swapping on the backplane?

  No, removing or inserting the CPU processor while power is applied disrupts the backplane bus and damages logic circuits.

• What is the current draw of the CQM1H-CPU21 from the internal 5 VDC rail?

  The processor unit draws 0.82 A continuously from the 5 VDC backplane supply provided by the system power module.

• What function does the onboard Inner Board expansion slot serve?

  The Inner Board slot allows installation of specialized motion control, high-speed counter, or analog I/O option modules.

• How are the 16 integrated DC inputs powered?

  The 16 onboard DC inputs require an external 24 VDC power source wired directly to the input terminal block points.

• What causes the ERR/ALM LED indicator to illuminate on the front panel?

  The ERR/ALM LED turns on when a fatal system fault occurs, such as memory corruption, syntax errors, or bus time-outs.

• What ambient temperature limits must be maintained during panel operation?

  The module must operate within an ambient temperature range of 0 to +55 deg C to prevent thermal processing faults.

• Can the RS-232C port communicate directly with peripheral operator interfaces?

  Yes, the integrated RS-232C port supports point-to-point serial communication using Host Link or NT Link protocols.

• How does the CPU maintain program memory during main power loss?

  Internal RAM memory and clock data are sustained by an integrated backup battery when external system power is removed.