-24-
No.EX##-OMM0008-B
•
List of Troubles and Countermeasures
Trouble
No.
Problem
Possible cause
Investigation method
Countermeasure
Failure of wiring
Check the communication power supply
cable is not opened, and that there are
no loose connections between the
power supply cable and terminal.
Check there is no repeated bending and
pulling force applied to the cable, which
will cause breakage.
Connect the power supply
cable correctly.
Check proper wiring of communication
power supply.
Correct the wiring.
1
MS_LED at SI unit
goes off
Failure in power
supply
Check the supply voltage to the power
supply
Supply 14 VDC to 26.4
VDC to the power supply
for SI unit.
2
Red light of MS_LED
at SI unit is lit up
Failure in SI unit The product has failed.
Replace the SI unit with a
new one.
3
Red light of MS_LED
of SI unit is blinking
Incorrect setting
of node address
Check there is no mistake with the set
node address.
Set correctly.
4
SI unit
MS_LED green on
NS_LED goes off
Master unit
power supply
failure
Check the master unit is operating
properly.
Connect the master unit
to a proper power supply.
5
SI unit
MS_LED green on
NS_LED red on
Duplication of
node address
Check the set node address is not
duplicated by other slave units.
Set correctly.
Check the communication cable is not
opened, and that there are no loose
connections between the power supply
cable and terminal.
Check there is no repeated bending and
pulling force applied to the cable, which
will cause breakage.
Connect the
communication cable
correctly.
Check proper wiring of communication
cable.
Correct the wiring.
Check the terminal resistance (121
Ω
) is
installed only at both ends of the main
line.
Install the terminal
resistance (121
Ω
)
properly.
Check proper length of the cable
(main line and branch line).
Correct the wiring.
Check the existence of equipment and
high voltage line, which cause noise,
around the communication and power
supply lines.
Separate the cables for
communication and
power from the noise
sources.
6
SI unit
MS_LED green on
NS_LED red blinking
Communication
timeout
Check that all slaves are properly set.
Correct the wiring.