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MELSEC-Q
8 TROUBLESHOOTING
8.2.5 Items checked when an communication data error is detected
(1) Cyclic transmission
Check item Checking procedure
Is the sequence program correct?
Stop the CPU modules of both the remote master station and turn the link device of the
sending station on and off by GX Developer's test operation to check whether or not
data is sent to the receiving station.
If it is normal, review the sequence program.
If it is abnormal, review the remote master station's common parameters and refresh
parameters.
Are the parameter settings of the remote master
station correct?
Review the range of the link devices assigned to the sending station.
Check the setting of the refresh parameters to see in what range of LB/LW/LX/LY of the
network module the device range used by the sequence program is stored.
(2) Transient transmission
Check item Checking procedure
Has an error occurred while the transient
transmission was being executed?
Check the error code at the transient transmission execution and correct the error
according to the error code table in Section 8.3.
Confirm the message screen of GX Developer and the error code of the response
packet of the dedicated instruction/MELSEC communication protocol, and take
measures based on the error code table in section 8.3.
Confirm if transient transmission is executed for ACPU, QnACPU, or QCPU (except for
Redundant CPU) by specifying the control system or standby system (error code
4B00).
Confirm if transient transmission is executed for a single CPU system by specifying a
CPU No. of a multiple CPU system (error code 4B00).
Response timeout occurs.
Confirm if a value out of the available range is set up for the CPU type of the target
station.
Has the transient transmission is executed routing
via the network module of standby system within
the redundant system?
Change the routing settings of the network module on the control system.
Has a stop error occurred on the route CPU
module or the CPU module of the target station in
the redundant system?
Clear the stop error on the route CPU module or CPU module of the target station.
Change the route station No. or the station No. of the target station.
Are the routing parameter settings correct?
Check the routing parameters with the communication test of GX Developer's network
diagnostics.
Is the network No. parameter correct?
Check the network No. parameter.
If the parameter is not set, the network No. has been set to 1 (default); so check other
stations' network Nos.
8.2.6 Items checked when a link dedicated instruction does not complete
Check item Checking procedure
Is the mode of the remote master station set to
offline?
Set the mode of the remote master station to online and execute the link dedicated
instruction again.
Add SB0043 (Online switch (host)) as an interlock for execution of the link dedicated
instruction so that the instruction is not executed offline.