Pilz PMCprotego S1 Operating Manual page 27

4 Function Description
4.3 Safety functions
4.3.1 Safe torque off - STO
4- Sicherheitsfunktion_STO_Ueber_S1 Safe torque off - STO
Sicherheitsfunktion_Sxx_Voraussetzung_S1
Sicherheitsfunktion_Sxx_Voraussetzung_SIL3
Sicherheitsfunktion_STO_Ausloesung
Sicherheitsfunktion_STO_Ausloesung_S1
Sicherheitsfunktion_STO_Reaktion
The safety function "Safe Torque Off" (STO) removes the power to the
motor. It is implemented via the servo amplifier's shutdown path and the
safety card's safe outputs.
Features of the safety function:
The motor becomes torque-free and no longer generates any hazard-

ous movements.
To prevent the drive running down in an uncontrolled manner, in nor-

mal operation the safety function STO is activated via the safety func-
tion SS1.
STO is only activated directly when

– there is an internal error on the servo amplifier or safety card
– the STO delay time is set to 0
– the inputs "SS1 Activate" and "SS1 SIL3/Reset" simultaneously
switch to a "0" signal
The STO-ENABLE reset lock on the servo amplifier has no function if

the servo amplifier contains a safety card. The output contact is linked
internally. In this case, the safety card activates the safe pulse disa-
bler on the servo amplifier in order to shut down the power element.
The safety function "Safe Torque Off" corresponds to a category 0

stop (uncontrolled stop) in accordance with EN 60204-1.
Prerequisites for normal operation:
Input "SS1 Activate" and "SS1 SIL3/Reset": "1" Signal (+24 VDC)

"Ready" output: "1" Signal (+24 VDC). The safety card is ready for op-

eration.
"STO Acknowledge" output: "0" Signal

To achieve SIL3 or Ple: Connect the output "STO SIL3" to servo am-

plifier terminal X4A/ 3.
Safety function is activated
By an error after limit values have been exceeded or

By an internal error on the safety card or servo amplifier, if the drive

can no longer be braked safely
By executing the safety function SS1 (1/0 pulse edge). In this case the

drive is braked safely before it is switched to torque-free (see section:
"Safe stop – SS1").
The inputs "SS1 Activate" and "SS1 SIL3/Reset" simultaneously

switch to a "0" signal
A second error occurs while SS1 (drive shutdown) is activated.

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