The Omron CJ1W-CT021 is a high-speed counter unit designed for the CJ-series programmable controllers, offering precise and flexible control for industrial automation applications. This module supports two axes with a maximum input frequency of 500 kHz, enabling accurate counting and measurement in high-speed processes. It features two digital inputs (I0 and I1) and two digital outputs (O0 and O1), which can be configured for various functions such as gate control, reset, preset, and capture, providing versatile control options. The unit supports multiple counter types, including simple, circular, and linear counters, selectable via a DIP switch, allowing adaptability to different application requirements. Additionally, it offers a 32-bit counting range and includes a digital variable noise filter to ensure reliable operation in environments with electrical noise. The CJ1W-CT021 is compatible with line driver (RS-422) and open collector input signal types, enhancing its versatility in diverse industrial settings. Its compact design, with dimensions of 95.4 mm in height, 31 mm in width, and 83.6 mm in depth, and a weight of 94 g, facilitates easy integration into existing control systems. This module is ideal for applications requiring precise and high-speed counting, such as position control, speed monitoring, and process control in automated manufacturing systems.