Siemens SINAMICS G130 Operating Instructions Manual page 95

Note
Ensuring the function of digital inputs
An open input is interpreted as "low".
Terminal M1 must be connected so that the digital inputs (DI) can function.
This is achieved through one of the following measures:
1. Also route the reference ground of the digital inputs.
2. A jumper to terminal M. (Note: This removes the electrical isolation for these digital
inputs.)
Note
If the 24 V supply is briefly interrupted, then the digital outputs are deactivated during this
time.
Inverter chassis units
Operating Instructions, 07/2016, A5E00331449A
Electrical installation
4.10 Signal connections
95