Siemens AG 6ES5420-3BA11 Digital Input Module

Siemens AG 6ES5420-3BA11 is a SIMATIC S5 digital input module that provides 32 x 24 V DC digital inputs in a compact “K” housing for the 420-series I/O lineup. Designed for non-isolated inputs, it accepts standard 24 V DC field signals from sensors and switches and feeds binary states into the S5 controller, expanding the input capacity of legacy automation systems. As part of the SIMATIC S5 digital input family, this module integrates with the S5 backplane to support dense, straightforward digital sensing in industrial environments where space is at a premium. Typical applications include reading signals from pushbuttons, limit switches, and other 24 V DC devices in older Siemens control setups that still rely on 32-channel input density. Key specifications include 32 digital inputs, 24 V DC operation, compact form factor (K version), and a non-isolated input configuration tailored for the 420-series I/O. The 6ES5420-3BA11 serves as a purpose-built DI module for classic Siemens control architectures, delivering reliable binary sensing compatibility within existing S5 installations.