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Overview Section 6-1
6-1-6 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 mes-
sage destination).
Message monitoring timers are supported for both explicit message and FINS
message communications. The timers can be set with version 2 or later of the
DeviceNet Configurator. The default setting is 2 seconds (2,000 ms). The set-
ting range is 500 to 30,000 ms.
If the response from the remote communications device (message destina-
tion) is slow, the timer setting must be increased. In particular, responses take
time in FINS message communications that cross different network layers, so
this 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 monitoring based on the response monitoring time for
CMND, SEND(090), and RECV instructions. There will be no effect, therefore,
if either the message monitoring timer or the response monitoring time for
CMND/SEND/RECV instructions 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 CMND, SEND(090), and RECV
instructions the same as or longer than the message monitoring timer, i.e.,
CMND, SEND(090), RECV instructions ≥ message monitoring timer.
If a lot of timeouts occur, maintain this relationship but lengthen the time for
both.
Note When performing remote programming or monitoring from the CX-Program-
mer (scheduled to be supported by version 2.1 and later), set the message
monitoring timer in the CS/CJ-series DeviceNet Unit mounted to the PC con-
nected to the CX-Programmer to at least 20 s (20,000 ms). This setting is
required only for the Unit that will perform remote programming.
6-1-7 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 coun-
Master Status Area 1
CPU
Unit
Device-
Net Unit
Example: Routing table error
Flashing red
Not relevant