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Description of the safety function STO
Festo – GDCP-CMMS-AS-G2-S1-EN – 1306NH – English
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2.3.3
Restart after STO
Before switching it on again, make sure that all hazards have been eliminated and the system can be
safely placed in operation again. A manual acknowledgment must be made through the optional S2
pushbutton corresponding to the risk evaluation for the application (see switching example).
To switch the output stage of the motor controller active again and thus operate the connected motor,
the following steps must be taken (
timing diagram Section 2.3.4):
1. First, the control of the relay for switching the supply voltage of the output stage driver (2nd switch-
off path) must be switched through 24 V at Rel [X3.2] (related to 0 V [X3.3]).
This switches on the internal driver supply.
2. The driver supply is recharged after no more than 20 ms (t6).
3. The potential-free acknowledgment contact NC1/NC2 [X3.5/6] is opened no later than 30 ms (t4)
after Rel [X3.2] is switched.
4. The switching time for the output stage enable DIN4 [X1.21] is freely selectable (t7). The release
should take place simultaneously with activation of the 2nd switch-off path via Rel [X3.2], but must
be present at least 2.5 ms (t8)
before
the rising edge of the controller enable DIN5 [X1.9].
5. With the rising edge of the controller enable, after a time delay
≤
5 ms (t9), release of the motor
holding brake is triggered (if present) and the internal output stage enable takes place. For control
via the fieldbus, controller enable via fieldbus is also required beforehand.
With FCT, a switch-on delay can be set for the brake (t10), which causes the drive to be regulated to
speed “0” for the specified time, and only after this time has elapsed does it run to the set speed.
6. No later than 720 ms (t5) after ending of the 2-channel request, the “H” on the 7-segments display
goes out.