Operating manual
cyber
®
dynamic system
en-44
Doc. no.: 5022-D056658
Revision: 01
11.6 Function description
Use of the STO safety function requires the inputs STO and STO GND to be connected
to the outputs of a safety control or safety relay that fulfills at least the requirements of PLd
to EN 13849-1 or SIL 2 to EN 61508.
Single-channel control SIL 2 / PLd:
With single-channel control of the STO safety function, the STO input is switched on
by an output of a safety relay. The STO GND is permanently connected to the GND
of the safety relay.
STO +24 V status
STO GND status
Motor torque
possible
Open
0 VDC
No
+24 VDC
0 VDC
Yes
Two-channel control SIL 3 / PLe:
With two-channel control of the STO safety function, the STO and STO GND shutdowns
are switched separately by two outputs of a safety control.
STO +24 V status
STO GND status
Motor torque
possible
Open
Open
No
+24 VDC
0 VDC
Yes
When wiring the STO inputs inside an installation space, make sure
that both the wiring used and the installation space itself meet the
requirements of EN 60204-1.
If the wiring is outside the installation space, it must be routed in
a permanent installation and protected from external damage.
If the STO safety function is not required in an application, the STO
input must be permanently connected directly to +24 VDC and the
STO GND input must be permanently connected directly to GND.
The STO function is thus shunted out and cannot be used. The drive
system is then no longer a safety component as defined by the
Machinery Directive.
