Siemens SIMATIC Operating Instructions Manual page 118

Fail-Safe Electronic Modules
8.3 F -Switch PROFIsafe Digital Electronic Module
Assignable Parameters for Use Case 2.1
Set the "Type of sensor interconnection" parameter to "1-channel" for the corresponding
input. The discrepancy time is permanently preset to 10 ms and cannot be changed.
You can enable or disable the "short-circuit test" parameter. For digital inputs connected to
an external supply, set the "Sensor supply" parameter for the corresponding digital input to
"external". The program will otherwise report a "short circuit" diagnostics event if the "short-
circuit test" is enabled.
Special Features for Fault Detection in Use Case 2.1
The following table presents fault detection according to the sensor supply and the
parameter assignment for the short-circuit test:
Table 8-23
Short circuit of DI 0 with DI 1
Short circuit of DI 0 with DI 3
P-short circuit of DI 0
M-short circuit of DI 0
Discrepancy error
P-short circuit of sensor
supply
M-short-circuit in sensor
supply or defective
Short-circuit in sensor supply
at DI 0
Supply voltage fault
*: Fault is detected only in case of signal corruption. That is, the signal read differs from the sensor
signal (discrepancy error). If there is no signal corruption relative to the sensor signal, fault detection
is not possible and is not required from a safety standpoint.
If the short-circuit test is disabled or cannot be enabled, the wiring between the sensor and
input channel must be short circuit-proof.
118
F-Switch PROFIsafe Electronic Module: Fault Detection
Example of Fault
WARNING
Fault detection in case of ...
Internal sensor supply Internal sensor supply
and short-circuit test and short-circuit test
enabled
No
No
Yes
Yes*
Yes
Yes
Yes
No
Yes
ET 200pro Distributed I/O System - Fail-Safe Modules
disabled
No
No
No
Yes*
Yes
No
Yes
No
Yes
Operating Instructions, 05/2007, A5E00394073-02
External sensor
supply
No
No
No
No
Yes
No
Yes
No
Yes