NORD Drivesystems BU0230 - Manual (Page 35)

2 Description of function
BU 0230 GB-2712 35
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. Safety category 1 (and PL c) can be achieved for the digital inputs.
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.