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Digital modules
8.7 SM 326; F-DO 10 x DC 24V/2A PP (6ES7326-2BF10-0AB0)
Fail-safe signal modules
Installation and Operating Manual, 01/2010, A5E00085586-10
177
Diagnostic message Error detection Possible causes of the problem
Corrective measures
Load voltage 2L+, 3L not
connected
Connect 2L+ and 3L+
Defective load
voltage or load
voltage not
connected
general
Load voltage external error
Replace the module
CRC signature error general
CRC signature error during
communication between the CPU
and the module has occurred, for
example, due to electromagnetic
interference in excess, faults during
sign-of-life monitoring error, in case
of voltage drop or standard
program accesses F-SM.
Eliminate the
interference
Assigned monitoring time
exceeded
Check the monitoring
time parameters
Timeout of safety
message frame
monitoring
general
Startup of the fail-safe signal
module
—
Message frame
error
general
Sign-of-life and/or CRC signature
entered in the data message frame
Check the sign-of-life
and CRC signature
entries in the data
message frame for "0"
value
Switching frequency
too high
general
Switching frequency too high
Reduce the switching
frequency
Note
Note that an inductive load connected to the DO channels can induce voltages due to
interference of a strong, magnetic field. This situation can result in the diagnostic message
short circuit.
Remedy:
Create a spatial separation of the inductive loads and shield the magnetic field.
Configure the read-back time of the dark test with 50 ms or greater.
Note
In case of a wire break at an actuator with redundant control by two modules, both modules
will report a wire break. The wire break diagnostic will come at a later time.
Note
If the F-SM detects an external P-short circuit on a channel, it will turn off all channels that
route "1" signals and are not configured redundantly.
The channels that are actually affected will be determined afterwards; channels without
active fault can be reintegrated at this time.