What it is and what it does
The Siemens 3RK1903-1CA01 is an F-kit RS1-X for the ET200S distributed I/O system, designed to build a local safety reversing starter. It contains two auxiliary switch blocks, one contact holder with connecting cable, one jumper cable, and four contact carriers for the terminal module (TM). This kit supports safety applications up to Category 4 / Performance Level e per ISO 13849-1 and up to SIL 3 per IEC 62061, making it suitable for guarding hazardous motion on reversing drives — conveyors, transfer lines, or any load that needs controlled reversal in a safety circuit.
Lifecycle and sourcing posture
The substance prohibitance date of 05/01/2012 indicates compliance with RoHS and REACH substance restrictions as of that date — relevant for EU regulatory acceptance and for buyers who need to document material declarations on a BOM.
Integration context
This F-kit mounts onto the ET200S terminal module (TM) and connects to the safety-related backplane bus. It is not a standalone contactor — it is the accessory bundle that turns a standard ET200S output module into a safety-rated reversing starter with local control. The two auxiliary switch blocks provide feedback for the safety logic.