Siemens 6ES5420-4UA12 is a SIMATIC S5 digital input module (DI 420) that provides 32 DC 24 V inputs in the compact version U form factor. Designed for 24 V DC signaling from sensors and switches, this non-floating module is intended for use with the S5-135U/155U PLC family. It can also be used in an S5-115U system when mounted in adapter casing 6ES5491-0LB11-0DE0, expanding legacy automation capabilities. This 32-channel DI module enables reliable industrial signal acquisition for applications such as machine monitoring, safety interlocks, and process signaling in legacy Siemens S5 environments.
