9. TROUBLESHOOTING
IMR01Y36-E2
98
Continued from the previous page.
Problem Probable
cause
Solution
•
NS (or NET) lamp
OFF
•
MS (or MOD) lamp
ON (Green)
Wait for completion of Node
address duplication check with a
master
If only the COM-JH is in this state
though both of the NS/MS
(NET/MOD) lamps are lit in green,
re-start after checking that each
communication speed is the same
MS (or MOD) lamp
flashes (Green)
Controller communication error
Remove error factors from the
connection with the controller and then
make a re-start.
MS (or MOD) lamp
ON (Red)
Memory backup error
Replace COM-JH
•
NS (or NET) lamp
ON (Red)
Node address duplication
Re-start after the re-setting is made so
that no Node address is duplicated
•
MS (or MOD) lamp
ON (Green)
Bus off status (communication stop
by data abnormality frequent
occurrence)
Re-start after checking the following
items.
•
Does the speed coincide with the
master communication speed ?
•
Is not the DeviceNet communication
cable connected yet, incorrectly
connected or removed ?
•
Is the length of the DeviceNet
communication cable appropriate ?
•
Are termination resistors (121
Ω
)
connected only to both ends of the
trunk line ?
•
Does much noise exist ?
Breakdown of communication
device
Replace COM-JH
•
NS (or NET) lamp
flashes (Red)
•
MS (or MOD) lamp
ON (Green)
DeviceNet communication
I/O connection time-out state
•
Set the I/O connection Expected
packet rate (class: 0x05, instance: 2,
attribute: 9) to 0 (No time-out) or set
it to a sufficiently large value.
•
Lengthen the master I/O message
communication cycle time.
Continued on the next page.
