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MELSEC-QnA
13 TROUBLESHOOTING
Trouble description Details to be checked Confirmation action
Is the corresponding local station performing
data link?
Does the occupied station count setting of
the local station match the station
information of the master station?
Check the LED indication of the corresponding local
station.
Check Other station data link status (SW0080 to
SW0083) of the master station.
Is data written to the correct address of
remote register RWw (buffer memory) at the
master station?
Verify the sequence program.
Is data read from the correct address of the
remote register RWr (buffer memory) at the
local station?
Verify the sequence program.
Is the station incorrectly set as reserved? Verify the parameters.
Unable to communicate from the
master station (remote register RWw)
to the local station (remote register
RWr).
Did the station number overlap? Verify the station number.
Is the corresponding local station performing
data link?
Check the LED indication of the corresponding local
station.
Check Other station data link status (SW0080 to
SW0083) of the master station.
Is data written to the correct address of
remote register RWw (buffer memory) at the
local station?
Verify the sequence program.
Is data read from the correct address of the
remote register RWr (buffer memory) at the
master station?
Verify the sequence program.
Is the station incorrectly set as reserved? Verify the parameters.
Unable to communicate from the local
station (remote register RWw) to the
master station (remote register RWr).
Did the station number overlap? Verify the station number.
Is the data link stop (SB0002) turned on? Verify the sequence program. Unable to stop data link.
Did an error occur? Verify the data link stop result (SW0045).
Is the data link stop (SB0000) turned on? Verify the sequence program. Unable to restart data link.
Did an error occur? Verify the data link restart result (SW0041).
Is the parameter registration request (YnA)
to the E
2
PROM on?
Verify the sequence program.
Parameter cannot be registered in
E
2
PROM.
Any errors occurred?
Verify the E
2
PROM registration status (SW00B9).
Are the station information in the parameters
and the settings as the module which does
not start up consistent?
Verify the parameters. Remote/local station does not start up.
Overlapping with other module's station
number?
Verify the station number setting switch.
Set as an error-invalid station? Verify the parameters. Faulty stations cannot be detected.
Did the station number overlap? Verify the station number.
Can a faulty station be identified using Other
station data link status (SW0080 to
SW0083)?
Faulty stations arise due to
transmission speed.
Can communicate normally when changed
to slower transmission speed like 156 kbps?
• Verify the faulty station switch setting.
• Verify if the wiring is correct.
• Verify if the cable shield has been grounded.
Did an error occur? • Verify the CPU's error code.
• Verify the master station's error code.
The abnormal completion bit turns on
when executing a dedicated
Is an automatic refresh parameter set? Set the automatic refresh parameter using the
software package.