Wiring the safety inputs

Attention

For SIL 3, PL e, cat.3 it is required to detect or prevent cabling faults. This can be achieved by:

  • sending test pulses from the PLC OR

  • ensure fault exclusion for wiring “Short circuit between any two conductors” according to ISO 13849- 2:2012 between signals STO-SBC 1 and STO SBC 2. The fault exclusion can be claimed by:

    • permanently connected (fixed) and protected against external damage, e.g. by cable ducting, armouring, OR

    • separate multicore cables, OR

    • installation within an electrical enclosure, OR

    • individually shielded with earth connection.

Cabling lenghts

Please observe the maximum allowed cable lengths:

Connection

Maximum wire length

STO-SBC

30 m

Connection diagrams for the STO inputs

Important

Please note that Safety GND is an isolated signal from drive GND.

Manual switch + drives

Allows safety functions up to SIL 3, PL e, cat.3.

../../../../_images/daisy_chain_STO-SBC_switch_nth1.png

Safety PLC PM (Plus-Minus output) + drives

Allows safety functions up to SIL 3, PL e, cat.3.

Note

Safety GND functions as a secondary line when a PLC with Plus-Minus output is used.

../../../../_images/daisy_chain_STO-SBC_PLC_PM_nth1.png

Attention

In case of multiple drive connection, ensure that the output driver has sufficient current driving capability.

Safety PLC PP (Plus-Plus output) + drives

Allows safety functions up to SIL 3, PL e, cat.3.

../../../../_images/daisy_chain_STO-SBC_PLC_PP_nth1.png

Attention

In case of multiple drive connection, ensure that the output driver has sufficient current driving capability.

Connection diagram for the brake

../../../../_images/STO-SBC_wiring_brake2.png

Now you are ready to use the feature:

Safety functions