Diagnostics of safety modules
(Original Document)
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At a Glance
A faulty module will be indicated by the lighting up or flashing of the RUN, ERR and I/O LEDs.
There are three classes of fault:
Internal faults are the result of a Safety module self-checks.
External faults are linked to the Safety module external supply.
State of module
The following table allows a diagnosis to be made on the basis of the three LEDs: RUN, ERR and I/O.
State of module
Status LEDs
RUN
ERR
I/O
Rack off or module fault
Normal operation or module not recognized if no supply
Inoperative module
External supply fault
Module and external supply fault
External fault: 24 Vdc (<19 Vdc) external supply
Internal fault (module faulty)
General fault (short circuit, etc.)
Legend:
LED off
LED on
Safety system status
The following table enables us to determine the status of the safety system using LEDs 0 to 31:
LEDs
State
Meaning
0 to 23
SS ESD or PS contact open
SS ESD or PS contact closed
24
Reactivation input open or feedback loop open
Reactivation input closed and feedback loop closed
25
Feedback loop open
Feedback loop closed
26
K1 and K2 SS relays non-controlled
K1 and K2 SS relays controlled
27
SS supply fault or fault causing a short circuit between Safety system channels
SS supply present
28 to 31
LED not in use
Legend:
LED off
LED on
SS
Safety System
NOTE: An external supply fault causes the module I/O LED to come on. The display block LEDs always show channel status, even if there is a fault on the channel.
It is possible to set up external supply surveillance: for this, the LEDs of the display block reflect the real status of the SS ESD or PS.