Omron OMNUC FND Series User Manual page 221

Position drivers
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Application
j Error Diagnosis by Means of Operating Status (CompoBus/S Only)
Symptom
There is an error in the com-
munications data.
Communications will not
start.
Note If a communications error occurs, refer to the operation manual for the Master Unit.
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Probable cause
The node address is over-
lapping another node
address.
The Programmable Control-
ler's load shutdown bit has
turned ON.
The communications cable
connection or the commu-
nications cable itself is
faulty.
f
lt
There is no terminating
resistance connected, or it
is connected at some posi-
tion other than the farthest
Unit.
The Master Unit is not con-
nected at the end of the
main line.
The length of the main line,
a branch line, or the total
length is greater than the
prescribed limit.
VCTF cable is combined
with special flat cable.
The Master is for a CQM1
System, and the Program-
mable Controller occupies
either two or four words,
and a node address is set
which is not permitted for
nodes 0 to 7. (An "address
over" error is generated.)
Items to check
Check the node address
settings of all the Slaves.
Check the status of the Pro-
grammable Controller's load
shutdown bit.
Check the connections. (If a
flat cable is being used,
check the connector area.)
Check the connectors.
Check the conductivity of
the communications cable.
Check the location of the
terminating resistance.
Check the location of the
Master Unit.
Check the lengths of the
main and branch lines, and
the total combined length.
Check the cables that are
being used.
Check the number of words
occupied by the Master
Unit's Programmable Con-
troller, and the number of
points occupied per node
address.
Chapter 4
Countermeasures
Correctly set the node
addresses.
Turn OFF the load shut-
down bit.
Connect the cable properly.
Replace the connectors if
necessary.
Replace the cable if neces-
sary.
Connect the terminating
resistance at the last Unit.
Connect the Master Unit at
the end of the main line.
Correct the wiring so that
the lengths of the main and
branch lines, and the total
combined length, are within
the prescribed limits.
Use either VCTF or flat
cable, but not both together.
Change the number of
words occupied by the Pro-
grammable Controller and
the number of points occu-
pied per node address.
4-29

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Troubleshooting

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