3
Safety conditions
Requirements on external safety controllers and safety relays
Manual – MOVIGEAR
®
B
16
3.3
Requirements on external safety controllers and safety relays
A safety relay can be used as an alternative to a safety controller. The following re-
quirements apply analogously.
•
The safety controller and all other safety-related subsystems must be approved
and tested for at least that safety class which is required in the overall system for
the respective, application-related safety function.
The following table shows an example of the required safety class of the safety
controller:
Application
Safety controller requirements
Performance level e according to
EN ISO 13849-1
Performance level e according to
EN ISO 13849-1
SIL 3 according to EN 61508
SIL 3 according to EN 62061
Performance level e according to
EN ISO 13849-1
SIL 3 according to EN 61508
•
The wiring of the safety controller must be suitable for the required safety class,
(see manufacturer documentation). The STO input of the MOVIGEAR
®
drive unit
requires 2-pole disconnection (sourcing/sinking).
•
MOVIGEAR
®
does not detect short circuits in the STO control cables. For this
reason, the safety control or the safety relay must detect crossfaults and interfer-
ence voltage of the STO control cable against any external potential, also cross-
faults and interference voltage against mass or PE.
•
The values specified for the safety controller must be strictly adhered to when
designing the circuit.
•
The switching capacity of the safety relays or the relay outputs of the safety con-
troller must correspond at least to the maximally permitted, limited output current
of the 24 V voltage supply.
Observe the manufacturer's instructions concerning the permitted contact loads
and fusing that may be required for the safety contacts. If the manufacturer
provides no specific information, the contacts must be protected with 0.6 times the
nominal value of the maximum contact rating specified by the manufacturer.
•
To ensure protection against unintended restart in accordance with EN 1037, the
safe control system must be designed and connected in such a way that resetting
the control device alone does not lead to a restart. A restart may only be carried
out after a manual reset of the safety circuit.
•
Note the following for two-pole disconnection of MOVIGEAR
®
with tested, safe out-
puts:
– When disconnected, the switch-on test pulses may never occur at the plus and
minus output at the same time.
22746250/EN – 12/2016
