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.
