Fail-Safe Modules
7.6 EM 4 F-DI/3 F-DO DC24V PROFIsafe digital electronic module
ET 200S Distributed I/O System - Fail-Safe Modules
Installation and Operating Manual, 08/2008, A5E00103686-07
151
Special Features of Fault Detection in Application 1.2
The following table presents fault detection according to the sensor supply and the
parameter assignment for the short-circuit test:
Table 7- 30 EM 4 F-DI/3 F-DO DC24V PROFIsafe: Fault detection
Error detection condition ... Example of fault
Internal sensor supply
and short-circuit test
are activated
Internal sensor supply
and short-circuit test
are deactivated
external sensor
supply
Short-circuit DI0 with DI1 Yes* Yes* Yes*
Short-circuit DI0 with DI4 No No No
Short-circuit DI0 with DI5 Yes* Yes* Yes*
P short-circuit DI0 Yes* Yes* Yes*
M short-circuit DI0 Yes* Yes* Yes*
Discrepancy error Yes Yes Yes
P-short circuit in sensor
supply
Yes No No
M-short circuit in sensor
supply or defective
Yes Yes Yes
Short-circuit SS with DI0 Yes* Yes* Yes*
Supply voltage fault Yes Yes Yes
*: Fault is detected only in case of signal corruption. In other words, the signal read differs from the
sensor signal (discrepancy error). If there is no signal corruption with respect to the sensor signal,
fault detection is not possible and is not required from a safety standpoint.
WARNING
If the short-circuit test is not activated or the sensor supply to digital inputs is set to
"external", the wiring between the sensor and the input channel must be short circuit-proof.