Diagnostic message
Possible cause of error
Remedy
Wire break
Lines interrupted
Connect the cable
No external sensor supply
Wire sensors with10 to 18 kΩ.
Channel not connected (open)
Disable the "Diagnostics – Wire break"
parameter for the channel in STEP 7.
Wire the channel
Fuse blown
One or more fuses on the module
has blown and caused this fault.
Remove the overload and replace the
fuse.
Sensor supply missing Overload at sensor supply
Eliminate overload
Short-circuit of sensor supply to M Eliminate the short-circuit.
Load voltage L+ miss‐
ing
Power supply L+ to module missing Feed in supply voltage L+.
Fuse in module is defective
Replace the module
Digital modules
4.4 Diagnostics for digital modules
S7-400 Automation System Module Data
92
Reference Manual, Ausgabe 11/2016, A5E00850736-08