Siemens SINAMICS Series Function Manual page 79

5.3 Control of "STO" and "SS1" via terminals on the Control Unit and the Motor/Power Module
Note
An open input is interpreted as "low".
To enable the digital inputs (DI) to function, terminal M2 must be connected.
This is achieved by:
1. Providing the ground reference of the digital inputs, or
2. A jumper to terminal M.
This removes isolation for these digital inputs.
Note
If the 24 V supply is briefly interrupted, the digital outputs are deactivated for this time.
Wiring
The control cables should be permanently routed (e.g. cable duct, retained using cable ties).
Signal cables and encoder cables should be installed separated from one another.
The shields of the control cables should be grounded through the largest possible surface
area immediately after they enter the control cabinet.
Outside the control cabinet the cables must be routed in such a way that they are safe to
walk on (e.g. as specified in IEC 60204-1).
Safety Integrated
Function Manual, 07/2016, A5E03264275A
Controlling the safety functions
79