Siemens SIMATIC Operating Instructions Manual page 102

Fail-Safe Electronic Modules
8.2 4 /8 F-DI/4 F-DO DC24V/2A PROFIsafe Digital Electronic Module
Diagnostic
Message
Communicatio
n error
Safety-related
shutdown
Generally Applicable Information on Diagnostics
For information on diagnostics pertaining to all fail-safe modules (e.g., for reading out
diagnostic functions, passivating channels), refer to
102
Fault Possible Causes
Detection
Always
Error in communication
between the F-CPU and
module due to defective
PROFIBUS/Industrial
Ethernet connection or
higher than permissible
electromagnetic
interferences, for example
PROFIsafe monitoring time
set too low
Configuration of the F-
module does not match the
fail-safe program
Always Process signal is faulty
Sensor is defective
Short circuit between
unconnected sensor cable
(open switch) and the
sensor supply cable
Wire break in connected
sensor cable (closed
switch) or sensor supply
cable
Assigned discrepancy time
is too short
Switching frequency
exceeded
Corrective Actions
Test PROFIBUS/Industrial Ethernet
connection. Eliminate the interferences.
Reduce the call interval for F-program,
or
Set a higher value for the "F-monitoring
time" parameter for the module in
STEP 7 HW Config
Recompile the safety program; then
reload the configuration and safety
program to the F-CPU
Check process signal. Replace sensor
if necessary.
Eliminate short circuit
Eliminate broken wire
Check the assigned discrepancy time.
Once the error is eliminated, the F-
module must be reintegrated in the
safety program.
Reduce the switching frequency
"Diagnostics"
.
ET 200pro Distributed I/O System - Fail-Safe Modules
Operating Instructions, 05/2007, A5E00394073-02