YASKAWA MP900 Series User Manual page 71

Network Maintenance
6.4.1 Masters
Problem
Communica-
tions are occur-
ring but the
receive data
refresh is
delayed.
MSG-SND func-
tion terminated
due to error.
(during
DeviceNet com-
munications)
MSG-SND func-
tion remains
BUSY and does
6
not end.
Locations to Check
Indicator Status I/O Status
MS lit green 8004 8000
NS lit green
MS lit green 8004 8000
NS lit green
MS lit green 2004 -
NS flashing
green
MS lit green 4004 40XX
NS lit red
MS lit green 8004 8000
NS lit green
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Table 6.5 Troubleshooting the Master (Cont'd)
Probable
Cause
Too much traf- 1. Set a longer communications cycle time.
fic on
2. Reduce the baud rate.
DeviceNet.
3. Increase the setting of the CPU scan time for
The communi-
cations cycle
time setting is
too low for the
I/O response
receive time.
The processing
load for data
exchange with
the PLC is too
large.
Parameter set- Check that the MSG-SND function parameter set-
ting error tings are correct.
• Data address
• Data size
EM allocations Set the EM allocation under I/O Allocations.
not made.
I/O communi- Remove the cause of the I/O communications error.
cations error
MSG-SND Check that the MSG-SND function parameter set-
function tings are correct.
parameter set-
• Remote station number
ting error
Too much traf- 1. Set longer communications cycle time.
fic on
2. For multi-Master configuration, increase the
DeviceNet
communications cycle time for other Master.
(Cannot send
Explicit request
message.)
6-10
Possible Solution
the I/O allocation SCAN setting.