The Omron CJ1W-CT021, also cataloged as the CJ1W-CT021 High-speed Counter Unit, operates as a dedicated hardware component for high-frequency pulse counting and encoder feedback processing within SYSMAC CJ/NJ Series systems.

Technical Identifier Matrix

• Base Hardware Model: CJ1W-CT021
• Full Part Number: CJ1W-CT021
• Product Type: High-speed Counter Unit
• Series Family: Omron SYSMAC CJ/NJ Series
• Module Classification: Special I/O Unit
• Counter Channels: 2 independent channels
• Maximum Input Frequency: 500 kHz

Hardware Specifications

Omron Backplane Bus Velocity & Real-Time Logic Execution

The CJ1W-CT021 transfers pulse count data directly to CPU memory via the high-speed CJ/NJ internal backplane bus. High-speed hardware counting operates independently of CPU cyclic scan timing, maintaining precision tracking at pulse input frequencies up to 500 kHz. Maximum output response time is bounded at 0.5 ms for direct execution of onboard comparative control routines. Flash firmware compatibility ensures deterministic signal processing without introducing processing delays onto the backplane.

Package Contents & Ordering Information

• 1x Omron CJ1W-CT021 High-speed Counter Unit
• 1x External input/output connector shell kit
• 1x Hardware specification instruction sheet

Field Installation Guidelines

• Backplane Assembly: Slide the CJ1W-CT021 onto the CJ/NJ CPU or expansion rack guide rails until the backplane bus connector fully seats into place.
• Wiring Setup: Route encoder and pulse signal conductors through dedicated shielded cabling away from 230 VAC power lines to prevent signal interference.
• Shielding Standard: Connect high-frequency pulse input cable shields to the system grounding bar using a 360-deg braid grounding clamp.
• System Grounding: Ensure the CPU base rack functional earth terminal connects directly to a panel ground bar with total ground loop resistance under 100 Ohms.

Frequently Asked Questions

• Is hot-swapping permitted for the CJ1W-CT021 module on CJ/NJ series backplanes?

  No. System power to the CPU rack must be isolated prior to insertion or removal of the module to prevent backplane bus damage.

• What maximum current draw does the CJ1W-CT021 place on the 5 VDC internal rack bus?

  The unit draws a typical internal current of 280 mA at 5 VDC, with a maximum rated current consumption of 370 mA at 5 VDC.

• What is the highest pulse input frequency supported by the counter channels?

  Each of the 2 independent counting channels supports input pulse frequencies up to a maximum limit of 500 kHz.

• What total response time is achieved for onboard comparative output switching?

  The internal circuit processing delivers a maximum response execution time of 0.5 ms for output switching functions.

• What backplane bus mechanism transfers high-speed counter values to the CPU?

  The unit utilizes direct memory mapped I/O access across the CJ/NJ backplane bus during each cycle refresh phase.

• What cable shielding method must be applied to high-frequency pulse inputs?

  Pulse signal lines require twisted-pair conductors enclosed in continuous 360-deg braid shielding bonded to panel chassis ground.

• What grounding resistance parameter must be maintained at the panel terminal?

  The system ground terminal must be wired to the panel protective copper earth bus with a resistance strictly under 100 Ohms.

• What temperature storage boundaries apply to uninstalled spare units?

  Spare units must remain sealed within anti-static packaging inside storage environments between -20 and +75 deg C non-condensing.