Fail-Safe Modules   
7.5 4/8 F-DI DC24V PROFIsafe Digital Electronic Module 
  ET 200S Distributed I/O System - Fail-Safe Modules 
116  Installation and Operating Manual, 08/2008, A5E00103686-07 
Assignable Parameters for Application 1 
Set the "Sensor evaluation" parameter to "1oo1" for the corresponding input. 
You can activate or deactivate 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 activated. 
Special Features of Fault Detection (Application 1)  
The following table presents fault detection according to the sensor supply and the 
parameter assignment for the short-circuit test: 
Table 7- 19  EM 4/8 F-DI DC24V PROFIsafe: Fault Detection (Application 1) 
Fault detection if ... 
Example of Fault 
internal sensor supply 
and short-circuit test 
activated 
internal sensor power 
supply and short-
circuit test are 
deactivated 
external sensor 
supply 
Short circuit in DI 0 with DI 1  No  No  No 
Short circuit in DI 0 with DI 4  Yes* No  No 
P-short circuit in DI 0  Yes  No  No 
M-short circuit in DI 0  Yes* Yes* No 
Discrepancy error  -  -  - 
P-short circuit in sensor 
supply 1 
Yes  no  No 
M-short circuit in sensor 
supply 1, or sensor supply 2 
defective 
Yes  Yes  Yes 
Short circuit in sensor supply 
1 with sensor supply 2 
Yes  no  no 
Fault in read/test circuit  Yes  Yes  Yes 
Supply voltage fault  Yes  Yes  Yes 
*: Fault detection only if signals are corrupted. That is, the signal reading differs compared to the 
sensor signal. 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.