Fail-Safe Input - Siemens SINAMICS G120 Operating Instructions Manual

6.2

Fail-safe input

This manual describes the STO safety function with control via a fail-safe input. All other
safety functions, further fail-safe digital inputs of the inverter and the control of the safety
functions via PROFIsafe are described in the Safety Integrated Function Manual.
Specifying the fail-safe input
If you use the STO safety function, then you must configure the terminal strip during the
basic commissioning for a fail-safe input, e.g. with p0015 = 2 (see Section Selecting the pre-
assignment for the terminal strip (Page 60)).
The inverter combines digital inputs DI 4 and DI 5 to form a fail-safe input.
What devices can be connected?
The fail-safe input is designed for the following devices:
● Connection of safety sensors, e.g. emergency stop command devices or light curtains.
● Connection of pre-processing safety relays, e.g. fail-safe controllers.
Signal states at the fail-safe input
The inverter expects signals with the same state at its fail-safe input:
● High signal: The safety function is deselected.
● Low signal: The safety function is selected.
Special measures for wiring of a fail-safe input
The inverter evaluates deviations in the two signals of the fail-safe 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
You have the following options to reduce the risk of damaged cables during operation of your
machine or plant:
● Use shielded cables with grounded shield.
● Lay signal cables in steel pipes.
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB
You must enable STO to select the STO safety function via FDI 0.
See also Section: Safe Torque Off (STO) safety function
(Page 302).
Adapt terminal strip
6.2 Fail-safe input
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