Safety Circuit / Restart Lock (STO)
Fig. 55: OSSD signals
The safety circuit is controlled by the OSSD1+2 signal or via one or several emergency
stop switch devices. see also
chapter 12.2 “Wiring Example”, page 103
.
If the OSSD signals or at least one of the +24 V conductors fail, the safety circuit switch-
es the pulse pattern of the output stage control sectors off. The response time of the
restart lock is
max. 4 ms
.
The restart lock must only be controlled when
▶
the drive is at a secure standstill (stop category 2),
▶
the higher-ranking control has deactivated the drive module,
▶
(reference speed value 0)
▶
the holding brake of the motor has been arrested.
Fig. 56: Safety circuit control
102
Drive System SD2M - Hardware Description 036228xxF
STO
function
acc. to
EN ISO
13849-1:2008-12,
DIN EN 62061:2005
SIL
3
not
possible
