Mitsubishi Electric MELSEC-L Series - The E71 Frequently Fails to Receive a Message Sent from the Connected Device; A Dedicated Instruction Is Not Completed

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CHAPTER 16 TROUBLESHOOTING
16
16.6 Troubleshooting by Symptom 16.6.2 The E71 frequently fails to receive a message sent from the connected device.
16.6.2 The E71 frequently fails to receive a message sent from the
connected device.
The following table lists how to troubleshoot the problem when the E71 frequently fails to receive a message sent from
the connected device.
*1 Availability depends on the version of the E71. ( Page 310, Appendix 3)
If the action above does not solve the problem, perform the following tests on the E71 to check for hardware error.
• Hardware test ( Page 333, Appendix 6.2)
• Self-loopback test ( Page 332, Appendix 6.1)
16.6.3 A dedicated instruction is not completed.
The following table lists how to troubleshoot the problem when a dedicated instruction is not completed.
If the action above does not solve the problem, perform the following tests on the E71 to check for hardware error.
• Hardware test ( Page 333, Appendix 6.2)
• Self-loopback test ( Page 332, Appendix 6.1)
Check item Action
Has the error code C0C7
H
been stored in Error code/end
code (address: E5
H
) in the error log block?
There may be a heavy load on the Ethernet line due to data sending and
receiving between connected devices.
• Taking action such as separating networks or decreasing the number of data
sending reduces the load on the Ethernet line.
• Consult the network administrator and reduce the load on the Ethernet line.
Has 1
H
been stored in Receive buffer full detection signal
(address: 5240
H
)?
*1
• Taking action such as separating networks or decreasing the number of data
sending reduces the load on the Ethernet line.
• When communications using a fixed buffer is used, check whether the
BUFRCV instruction is executed. ( Page 125, Section 12.4.1)
• To receive data at shorter intervals than the scan time of the CPU module
using a fixed buffer, add the normally closed contact for the completion
device of the BUFRCV instruction to the execution conditions of the
BUFRCV instruction. ( Page 153, Section 12.9.3 (2) (b))
Has the number in Received TCP packet count (address:
1B8
H
and 1B9
H
) increased?
If the packets cannot be received even though the number of received TCP
packets has increased, set the value of TCP Maximum Segment Transmission
setting area (address: 1E
H
) to 8000
H
. Then perform the initial process again.
( Page 311, Appendix 4)
Check item Action
Is the network parameter mode set to "Online"?
Set the network parameter mode to "Online".
( Page 66, Section 7.1.2) (If a dedicated instruction is executed in the
"Offline" mode, no error occurs but the instruction is not completed.)