21
Systematic malfunction analysis
The sources of malfunctions occuring in CAN bus systems operating with several bus-based stations
must be analysed systematically since faulty components or incorrect settings can give rise to
negative interactions with intact bus devices in the CAN bus system. These unwanted interactions
can cause error messages in fully functional bus devices, which will make fault detection even more
difficult.
We recommend the following systematic fault finding procedure:
System malfunctions
- continued -
Step 1 (Start)
Detach terminal strips
in all bus-based
sensors!
Level electrode
Conductivity electrode
Pressure sensor
Temperature sensor
etc.
Step 3
Apply mains voltage
to bus devices of the
system
e. g.
NRS ...
and
NRG ...
Step 2
Plug in terminal strip
of the sensor of the
system
e. g.
NRS ...
and
NRG ...
(electrode)
System O.K.
Detach terminal strips
between bus devices
of the system
e. g.
NRS ...
and
NRG ...
System fault
Use fault-finding
list to identify
the fault(s).
Cut off power supply
to the equipment!
Check
Use fault-finding list to
correct the fault(s).
Final test
− Have all faults been
eliminated?
Check next system
Fig. 9
