NORD Drivesystems BU0530 - Manual (Page 24)

Functional safety with NORD SK 500E frequency inverters
24 BU 0530 GB-3712
This solution is preferable, especially in cases where the switching device only checks its safety outputs in the
course of an enabling cycle, as is the case with some electro-mechanical switching devices. A suitable
checking interval must be specified according to the safety requirements.
NOTE
A separate shielded cable must be used for the "safe pulse block" or "switch-off of the 24V
supply". When using a protective switching device with short-circuit monitored OSSD-outputs,
the safety outputs can be combined in a single cable.
NOTE
Only the "safe pulse block" or "switch-off of the 24V" supply fulfil the requirements of Safety
Category 4. This does not apply to the digital input.
The frequency inverter can only fulfil safety category 1 during the period between activation of
the safe pulse block via a digital input and activation via terminals 88 and 89.