Siemens 6ES5400-7AA12 is an eight-channel digital input module for the SIMATIC S5-110 family (commonly used with the S5-110A controller), delivering eight 24 V DC input points to the PLC. Each channel accepts a 24 V DC signal, enabling direct connection of sensors and switches to monitor digital states within an S5-110A system. The module measures 40 mm high, 170 mm long, and 150 mm wide and weighs 0.38 kg. The part is listed as 6ES5400-7AA12 (also seen as 6ES54007AA12); several resellers describe it as a discontinued S5 digital input card, with available refurbished or exchange options in the market.
