The National Instruments 9421 is a high-performance C Series digital input module designed for reliable data acquisition in demanding industrial environments. It features eight channels of sinking digital inputs, compatible with 12V and 24V logic levels, making it ideal for connecting to a wide range of industrial sensors, switches, and logic devices. With channel-to-earth ground isolation, the NI-9421 ensures the safety and integrity of your measurement system by protecting against noise and high-voltage transients. This module is fully compatible with both CompactDAQ and CompactRIO platforms, offering a flexible and robust solution for industrial control, monitoring, and test applications.