Siemens SIMATIC Operating Instructions Manual page 66

Fail-Safe Electronic Modules
8.1 8 /16 F-DI DC24V PROFIsafe Digital Electronic Module
Assignable Parameters for Use Case 1
Set the "Evaluation of the sensors" parameter to "1oo1 evaluation" for the respective input.
You can enable or disable the "Short-circuit test" parameter. However, you must disable the
short-circuit test as soon as at least one fail-safe digital input is externally supplied.
Otherwise, the "Short circuit" diagnostic is reported.
Specific Characteristics for Fault Detection (Use Case 1)
The following table summarizes fault detection according to the sensor supply and the
parameter assignment for the short-circuit test:
Table 8-5
Short circuit of DI 0 with DI 1
Short circuit of DI 0 with DI 4
P-short circuit of DI 0
M-short circuit of DI 0
Discrepancy error
P-short circuit of Vs1
M-short circuit of Vs1, or Vs2
defective
Short circuit of Vs1 with Vs2
Fault in read/test circuit
Supply voltage fault
*: Fault is detected only in case of signal corruption. That is, the signal read differs from the sensor
signal. If there is no signal corruption relative to the sensor signal, fault detection is not possible and
is not required from a safety standpoint.
66
F-DI Modules: Fault Detection (Use Case 1)
Example of fault
Internal sensor supply
Fault detection in case of ...
Internal sensor supply
and short-circuit test and short-circuit test
enabled
No
Yes*
Yes
Yes*
-
Yes
Yes
Yes
Yes
Yes
ET 200pro Distributed I/O System - Fail-Safe Modules
disabled
No
No
No
Yes*
-
No
Yes
No
Yes
Yes
Operating Instructions, 05/2007, A5E00394073-02
External sensor
supply
No
No
No
No
-
No
Yes
No
Yes
Yes