The Omron CJ1W-CT021 Programmable Logic Controller (PLC) Expansion Unit is a high-speed counter module designed for accurate pulse input measurement in industrial automation. It supports 2 channels of 32-bit counting with up to 500 kHz frequency input capability. This module offers versatile counter modes for position, speed, and length detection, ensuring precise control in motion applications. Operating on 24 VDC, it provides stable, noise-resistant performance in harsh environments. Manufactured by Omron, part of the Omron Programmable Logic Controller series, available under the Omron CJ1W Series.