Mitsubishi MELSEC LJ71C24, User Manual

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15 TROUBLESHOOTING
15.3.12 Communication error "CH1 ERR." or "CH2 ERR."
Symptom Cause Corrective action MC
Bi
di
re
ct
io
na
l
N
on-
procedural
Predefined
• There is an error in the
communication protocol or
transmission setting.
• Read the error code from the buffer memory
and check the error contents and change
the switch setting to the correct setting.
• There is an error in the on-
line mode switching
designation.
• Read the error code from the buffer memory
and check the error contents and correct the
designation contents.
• On-demand execution
generated an error.
• Read the error code from the buffer memory
and check the error contents and correct the
designation contents.
• The C24 detected an error
while transmitting data.
• Read the error code from the buffer memory
and take the corrective action corresponding
to the error contents.
• The C24 detected an error
while receiving data.
• Read the error code from the buffer memory
and take the corrective action corresponding
to the error contents.
• "ERR." LED turns on.
• The receive data clear
request is executed during
the dedicated instruction
execution.
• Read the execution result (error code) of
control data of the dedicated instruction for
which the abnormal completion signal has
turned on, and take the corrective action
corresponding the error contents.
• The communication
protocol mode is set to
other than "Predefined
protocol mode".
• Set the communication protocol mode to
"Predefined protocol mode".
• No protocol setting data
have been written to the
C24.
• Write the protocol setting data from the
predefined protocol support function of GX
Works2, and then execute the CPRTCL
instruction.
• The protocol
corresponding to the
protocol No. specified in
the control data for the
CPRTCL instruction is not
registered.
• By the predefined protocol support function
of GX Works2, read the protocol setting
from the C24.
On the protocol selection screen, check the
registered protocol and protocol No. for an
error.
• To the same channel,
multiple CPRTCL
instructions were
concurrently executed.
• Correct the sequence program so that, upon
completion of one CPRTCL instruction
execution, another is executed.
• When the predefined
protocol is executed,
the "ERR." LED turns
on.
• Incorrect control data are
specified for the CPRTCL
instruction.
• Correct the control data for the CPRTCL
instruction.