Module fit and supply
The Siemens 3RK1903-0CE00 is a SIMATIC ET 200SP digital input module with two 24 V DC inputs, occupying 1 byte of the backplane bus. It's pluggable on the terminal module — no tools needed for swap, but the base unit stays wired. Supply voltage range is 20.4 to 28.8 V DC, rated 24 V. The module supports brake control at 24 V DC, which is useful for holding brakes on vertical-axis drives.
Integration notes
Mounts vertically or horizontally in the ET 200SP station. Width is 15 mm — one slice on the DIN rail. Depth is 95 mm, height 196.5 mm. Main energy infeed uses screw-type terminals; load-side outgoing feeder also screw-type. Communication and supply voltage transmit via the backplane bus. The module has 2 poles for the main current circuit. Surge voltage resistance is rated 8 kV, and EMC immunity corresponds to severity level 3, ambient A (industrial sector) per IEC 60947-1. Vibration resistance is 2g; shock resistance is 5g for 11 ms. Relative humidity during operation is 5 to 95 %.