Manual – MOVIAXIS® MMD60B - Functional Safety
13
3
Requirements on the external safety controller
Safety Conditions
3.3
Requirements on the external safety controller
A safety relay can be used as an alternative to a safety controller. The following require-
ments apply analogously.
• The safety controller and all other safety-related subsystems must be approved 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:
• The wiring of the safety controller must be suitable for the required safety class, (see
manufacturer documentation). Safety circuits with MOVIAXIS
®
MMD60B must be
disconnected in a PM or PP switching manner.
• 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 controller
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 con-
tacts. 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
safety controllers 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.
• If the safety circuit is disconnected at both poles, the test pulses may not be applied
at the same time. The pulse blanking must not exceed 1 ms. The next pulse blanking
cannot reoccur earlier than after 1 s.
• When the safety relay is connected in a PM switching manner, the safety relay must
be able to detect a short circuit against ground on the M output.
Application
Safety controller requirements
Performance level d according to EN ISO 13849-1
Performance level d according to EN ISO 13849-1
SIL 2 according to EN 61508
SIL 2 according to EN 62061
Performance level d according to EN ISO 13849-1
SIL 2 according to EN 61508
684086667
t
< 1 ms
> 1 s
high
low
