Siemens 6ES7 231-0HC20-0XA0 Digital Input Module accepts 21–28 V DC signals and feeds discrete input data to a compatible Siemens PLC system. It is used to interface sensors and switches, converting their on/off states into digital inputs for automation tasks. The 21–28 V DC input range is a verified specification of this module, making it suitable for 24 V industrial sensing environments.
