The Siemens 6ES7274-1XK30-0XA0 is the SIM 1274 simulator module for the SIMATIC S7-1200 CPU 1217C. It provides 14 toggle switches for digital input simulation, plus 10 standard 24 V DC inputs and four 1.5 V differential inputs that mirror the CPU's onboard I/O. This is the dedicated test and commissioning tool for the 1217C – no other CPU variant supports it.
What the inputs mean for commissioning
The 14 input switches give you manual override for each simulated digital input, handy for forcing bits during PLC program debug. The 10x 24 V DC inputs handle standard sinking/sourcing signals at the CPU's logic level, while the 4x 1.5 V differential inputs replicate the high-speed encoder or sensor channels the 1217C supports. For field service techs: the differential inputs require a separate low-voltage source – don't feed them 24 V.