Product Description; Overview Of The Sto Function - Festo CMMO-ST Safe torque off Nstrucciones De Utilización

CMMO-ST Safe torque off
2

Product description

2.1

Overview of the STO function

The safely switched off torque function ("Safe Torque Off", STO) enables two-channel switching off of
the voltage supply of the motor connected to the CMMO-ST.
– As long as a logic 1 (+24 V) is present at both STO inputs, the motor can be operated.
– If there is a logic 0 (0 V) at one or both of the STO inputs, the voltage supply to the motor is inter-
rupted.
– The diagnostics contact only has low impedance (i.e. closed) if there is a logic 0 at both STO inputs.
– If both STO inputs again receive logic 1, the release (input ENABLE) must be reset.
Block diagram for function
+24 V DC
1
1
Input circuit (switch, relay,
safety switching device)
2
Power output stage in CMMO-ST
(only one phase shown)
Fig. 1 "Safely switched off torque" functional principle
Festo – CMMO-ST Safe torque off – 1210a English
2
3
STO1
STO2
3
3
4
+24 V DC load
2 times
+24 V DC load
Driver supply
Motor (only one phase shown)
4
M
27