16
Festo — CMMT-ST-C8-1C-...-S0 — 2021-04b
Installation
[X1A]
Pin
Type
Identifier
Function
X1A.
2
Digital input
#STO-A
Safe torque off, channel A
X1A.
3
#STO-B
Safe torque off, channel B
X1A.
4
Contact
STA-C1
Safe torque off acknowledge, diag-
nostic contact
X1A.
5
STA-C2
Tab. 5: Inputs and outputs for the safety sub-function STO
The motor controller cannot detect a cross circuit in the input circuit by itself.
1. Find out if detection of shorts across contacts is needed for the input circuit and diagnostic
contact wiring in the application.
2. If required, use a safety relay unit with detection of shorts across contacts.
STO connection example
In this example, the safety sub-function STO (safe torque off) is triggered by an input device that
makes the safety request (e.g. light curtain).
