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CHAPTER 16 TROUBLESHOOTING
16
16.6 Troubleshooting by Symptom
16.6.8 Data cannot be sent with communications using a fixed buffer.
16.6.8 Data cannot be sent with communications using a fixed
buffer.
The following table lists how to troubleshoot the problem when an E71 cannot send data with communications using a
fixed buffer.
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 connection with the connected device been opened?
(Check the corresponding bit of 5000
H
in the buffer memory.)
• Open the connection with the connected device.
• Check if the open/close processes for I/O signals and the OPEN/CLOSE
instructions are not used together for the same connection. If so, correct
the program.
• Read Open error code (address: 7C
H
) in the communication status
storage area. Then check the error details and correct the error.
Is the IP address setting of the connected device correct? Check and correct the IP address of the connected device.
Does the communication protocol (TCP/IP or UDP/IP) match
with that of the connected device?
Use the same communication protocol (TCP/IP or UDP/IP) as that of the
connected device.
Was the BUFSND instruction executed?
• Correct the execution conditions of the BUFSND instruction.
• Check if the send/receive process for I/O signals and the
BUFSND/BUFRCV instructions are used together for the same
connection. If so, correct the program.
Was the BUFSND instruction completed normally?
Check the error code in the BUFSND instruction completion status area
and correct the error.
Has the data length of the send data been set in the control
data?
Write the data length.
Is the communication status of the connected device
normal?
Correct the error in the connected device.
Has an open or initial error occurred in the error log area? Check and correct the error.
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