Message Communications Error Indications; Message Monitoring Timer; Message Communications Errors - Omron CJ1W-DRM21 Operation Manual

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Message Communications Error Indications

There are two ways to obtain information on communications errors that occur in message communica-
tions: 1) Using the error history in the DeviceNet Unit and 2) Using DeviceNet Unit displays, indicators,
and Master Status Areas.
1
Each time a communications error occurs, an error code is placed in an error record in the error
history kept in the RAM of the DeviceNet Unit. Up to 96 records can be stored in the error his-
tory. The time and date the record occurred is also recorded.
Master
Unit
2
You can use the MS and NS indicators and the 7-segment indicator on the front panel of the
DeviceNet Unit together with the *_Unit1Sta (Unit Status 1) in the CPU Unit to obtain informa-
tion on a communications error that has occurred. This information can be used as the basis for
troubleshooting.
*_Unit1Sta
(Unit Status 1)
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Message Monitoring Timer

A message monitoring timer monitors responses for the DeviceNet Unit. A timer can be set for each
device that will be communicated with (each message destination).
You can set the timers with the CX-Integrator. The default setting is 2 seconds (2,000 ms). The setting
range is 500 to 30,000 ms.
If the response from the remote communications device (message destination) is slow, the timer setting
must be increased. The next message cannot be sent to the same communications device during the
response waiting time, so the setting should not be set too high.
The DeviceNet Unit uses this timer to monitor message timeouts. The CPU Unit performs the monitor-
ing based on the response monitoring time for SendCmd instruction. There will be no effect, therefore,
if either the message monitoring timer or the response monitoring time for SendCmd instruction setting
only is increased or decreased. Both must be increased or decreased for there to be an effect.
Set the response monitoring time for the SendCmd instruction the same as or longer than the message
monitoring timer, i.e., Response monitoring time for the SendCmd instruction ≥ Message monitoring
timer.
If a lot of timeouts occur, maintain this relationship but lengthen the time for both.
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Message Communications Errors

The following table shows the main errors that occur when messages are sent or received. Refer to
Section 9 Troubleshooting and Maintenance for countermeasures and errors recorded in error history
that are not shown by the indicators.
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
Code Can be monitored from the CX-Integrator.
Code
96 records
Code
CX-Integrator
Monitor
MS
NS
NJ-Series Master
CPU Unit Unit
6 Message Communications
Example: Routing table error
MS
Flashing red
NS
Not relevant
6
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