Fail-Safe Modules
7.5 4/8 F-DI DC24V PROFIsafe Digital Electronic Module
ET 200S Distributed I/O System - Fail-Safe Modules
Installation and Operating Manual, 08/2008, A5E00103686-07
125
Specific Features of Fault Detection (Application 2.3)
The table below presents fault detection according to the sensor supply and the parameter
assignment for the short-circuit test:
Table 7- 22 EM 4/8 F-DI DC24V PROFIsafe: Fault Detection (Application 2.3)
Fault detection if ... Example of fault
Internal sensor supply and
short-circuit test are
deactivated
External sensor supply
Short circuit in DI 0 with DI 1 Yes* Yes*
Short circuit in DI 0 with DI 4 Yes Yes
Short circuit in DI 0 with DI 5 Yes* Yes*
P-short circuit in DI 0 Yes* Yes*
M-short circuit in DI 0 Yes* Yes*
Discrepancy error Yes Yes
P-short circuit in sensor supply 1 no no
M-short circuit in sensor supply 1, or
sensor supply 2 defective
Yes Yes
Short circuit in sensor supply 1 with
sensor supply 2
no no
Fault in read/test circuit Yes Yes
Supply voltage fault 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.
7.5.8 Application 3: Safety mode SIL3/Category 4/PLe
Assigning Inputs to Each Other
The EM 4/8 F-DI DC24V PROFIsafe has 8 fail-safe inputs, DI 0 through DI 7 (SIL2). A pair of
these inputs can each be used as one input (SIL3). The following assignment applies:
● DI 0 with DI 4
● DI 1 with DI 5
● DI 2 with DI 6
● DI 3 with DI 7
Sensor supply
The EM 4/8 F-DI DC24V PROFIsafe provides sensor supply Vs1 for Inputs 0 to 3 and sensor
supply Vs2 for Inputs 4 to 7. The sensor must be supplied internally.
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