Product Description

The Keyence CU-21A is a compact, standard-type control unit designed for industrial automation applications. It facilitates signal processing and synchronization in systems requiring precise control logic. The CU-21A accepts inputs from NPN open-collector sensors or contact-based devices, supporting two input channels with a minimum input time of 5 ms. It outputs control signals via a single-pole double-throw (SPDT) relay rated for 250 VAC at 2 A (resistive load). The unit operates on a 100–240 VAC power supply and consumes up to 7 VA. Its compact design weighs approximately 105 grams, making it suitable for space-constrained installations. Please note that this model has been discontinued, with the CU-21TA recommended as its successor.​

Technical Specifications

• Model: CU-21A
• Type: Standard
• Input Channels: 2
• Input Signal: NPN open-collector or contact-based (e.g., limit switches)
• Minimum Input Time: 5 ms
• Control Output:
• Relay: SPDT, 250 VAC, 2 A (resistive load)
• Transistor Output: Not available
• DC Output: 12 VDC ±10%, 200 mA max.
• Operation Modes: Standard, Synchronous
• Logic Function: AND logic
• Power Supply: 100–240 VAC ±10%, 50/60 Hz
• Power Consumption: 7 VA max.
• Operating Temperature: -10°C to +50°C (no freezing)
• Operating Humidity: 35% to 85% RH (non-condensing)
• Weight: Approximately 105 g