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3 TROUBLESHOOTING
3.4 Troubleshooting by Symptom
When the simple CPU communication function is used
■Communications cannot be performed with the communication destination.
When communications with the external device cannot be performed using the simple CPU communication function, check
the following items and take action.
If communications cannot be performed despite the check for the above items, the hardware failure may have been occurred.
Please consult your local Mitsubishi representative.
■Communications with the communication destination are unstable.
When communications with the communication destination using the simple CPU communication is unstable, check the
following items and take action.
If communications cannot be performed despite the check for the above items, the hardware failure may have been occurred.
Please consult your local Mitsubishi representative.
■Communications cannot be performed at the set execution interval.
When communications cannot be performed at the set execution interval in the simple CPU communication function, check
the following items and take action.
Check item Action
Does any error occur in the simple CPU communication diagnostics or simple
CPU communication error code in the CPU buffer memory?
Eliminate the error cause. When communications can be performed by
increasing the communication retry count and communication time-out period,
review the communication retry count and communication time-out period, or
check the line status of Ethernet communications with the external device,
such as a cable, hub, and router, to check if the line is busy.
Is the communication status of the simple CPU communication diagnostics or
the simple CPU communication status of the CPU buffer memory "preparing"?
Check the cable between the CPU module and hub and if the hub is operating
normally.
Is the module supporting the simple CPU communication function used? In "Product Information List" of "System Monitor", check the firmware version
of the target module, and ensure that the module supports the simple CPU
communication.
When the module being used does not support the simple CPU
communication, replace it with the module that supports the function.
Is the own station port number set in the external device configuration within
the range of 61696 to 65534?
When the communication destination of the simple CPU communication is a
Mitsubishi Electric programmable controller, the own station port number is
dynamically set within the range of 61696 to 65534.
When the own station port number is set within the range of 61696 to 65534 in
the external device configuration, the port numbers overlap, resulting in a
communication failure. Set the own station port number to a number other
than 61696 to 65534 in the external device configuration.
Check item Action
Does any error occur in the simple CPU communication diagnostics or simple
CPU communication error code in the CPU buffer memory?
Eliminate the error cause.
Is the retry of communications performed? Check the line status of Ethernet communications with the external device,
such as a cable, hub, and router, to check if the line is busy.
Check item Action
Is another Ethernet function executed simultaneously in the CPU module
where the simple CPU communication function is set?
Review the Ethernet function executed simultaneously in the CPU module
where the simple CPU communication function is set.
Is the service processing load of the CPU module of the communication
destination high?
• When the communication destination is the model for which service
processing setting is available, increase the number of times and the time of
service processing of the communication destination.
• If the communication destination supports the COM(P) instruction and
CCOM instruction, incorporate the COM(P) instruction and CCOM
instruction into the sequence program of the communication destination.
• Review the execution interval.
Is the Ethernet communication load high? Or, is the communication quality
low?
Check the line status of Ethernet communication with the external device,
such as a cable, hub, and router, to reduce the load and improve the
communication quality. (Check the buffer memory Un\G100/Un\G101 (receive
packet count per unit time (one second)) or Un\G102/Un\G103 (send packet
count per unit time (one second)) of the CPU module (built-in Ethernet port
part) and reduce the load and improve the communication quality.)
Is the response from the SLMP-compatible device delayed? (When the
SLMP-compatible device (QnA-compatible 3E frame) is used)
• Check the function execution status of the communication destination
(SLMP-compatible device).
• Review the execution interval.
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