Installing
4.9 Connecting the interfaces for the inverter control
4.9.6
Fail-safe digital input
To enable a safety function via the terminal strip of the inverter, you need a fail-safe digital
input.
Which devices are you allowed to connect?
The fail-safe digital input is designed for the following devices:
● Connection of safety sensors, e.g. emergency stop command devices or light curtains.
● Connection of pre-processing devices, e.g. fail-safe control systems and safety relays.
Signal state
The inverter expects signals with the same state at its fail-safe digital input:
● High signal: The safety function is deselected.
● Low signal: The safety function is selected.
Connecting P/P and P/M-switching fail-safe digital outputs
It is permissible to connect PP and PM-switching safe outputs to a fail-safe digital input.
Fault detection
The inverter compares the two signals of the fail-safe digital input. The inverter thus detects,
for example the following faults:
● Cable break
● Defective sensor
The inverter cannot detect the following faults:
● Cross-circuit of the two cables
● Short-circuit between signal cable and 24 V power supply
100
For specific default settings of the terminal strip, e.g. default
setting 2, the inverter combines two digital inputs to form one
fail-safe digital input FDI 0.
PP-switching digital output
PM-switching digital output
Operating Instructions, 09/2017, FW V4.7 SP9, A5E34263257B AF
SINAMICS G120C converter