Festo — CMMT-ST-C8-1C-...-S0 — 2021-04b
Installation
17
1
2
3
4
Fig. 6: STO sample circuit
1 Input device for safety request (e.g. light
curtain)
2 Safety relay unit
3 Servo drive
4 Drive axis
Information on the sample circuit
The safety request is passed on to the servo drive on 2 channels via the inputs #STO-A and #STO-B at
the connection [X1A]. This safety request results in the 2-channel switch-off of the driver supply to the
servo drive’s power output stage.
The safety relay unit can use the diagnostic contact STA to monitor whether the safe state has been
reached for the safety sub-function STO.
The CTRL-EN wiring shown is not required for the safety sub-function STO.
