Siemens SINAMICS G120D Operating Instructions Manual page 69

Connect safe P/P-switching outputs
PP-switching output
Fault detection
The converter compares the two signals of the failsafe digital input. The converter thus detects,
for example the following faults:
• Cable break
• Defective sensor
The converter cannot detect the following faults:
• Cross-circuit of the two cables
• Short-circuit between signal cable and 24 V power supply
Special measures to prevent cross-circuits and short-circuits
The routing of cables over longer distances, e.g. between remote control cabinets, increases the
risk of damaging cables. Damaged cables raise the risk of an undetected cross-circuit with power-
conducting cables laid in parallel. A cross-circuit can cause interruption to the transfer of safety-
related signals.
To avoid cross circuit faults and short-circuits, you must protect the cables between a sensor and
the converter; this can be done by routing the cables separately or in a steel pipe/duct
On and off test
The converter filters signal changes using on and off tests at the failsafe digital input using an
adjustable software filter.
Converter with the control units CU240D-2
Operating Instructions, 10/2020, FW V4.7 SP13, A5E34262100B AH
You may not connect safe P/P-switching outputs to a safe input.
Connecting a failsafe digital input (Page 358)
Installation
4.2 Electrical Installation
67