Siemens SIMATIC Operating Instructions Manual page 73

Specific Characteristics for Fault Detection (Use Case 2.2)
The following table presents fault detection according to the sensor supply and the
parameter assignment for the short-circuit test:
Table 8-9
Short circuit of DI 0 with DI 1
Short circuit of DI 0 with DI 4
Short circuit of DI 0 with DI 5
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 (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.
ET 200pro Distributed I/O System - Fail-Safe Modules
Operating Instructions, 05/2007, A5E00394073-02
F-DI Modules: Fault Detection (Use Case 2.2)
Example of fault
8.1 8 /16 F-DI DC24V PROFIsafe Digital Electronic Module
Fault detection in case of ...
Internal sensor supply and
short-circuit test disabled
Yes*
No
Yes*
Yes*
Yes*
Yes
No
Yes
No
Yes
Yes
Fail-Safe Electronic Modules
External sensor supply
Yes*
No
Yes*
Yes*
Yes*
Yes
No
Yes
No
Yes
Yes
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