Mitsubishi Electric MELSEC iQ-R02CPU - Communications Using the Random Access Buffer Cannot be Performed

3 TROUBLESHOOTING
3.4 Troubleshooting by Symptom
301
3
Communications using the random access buffer cannot be performed.
When communications using the random access buffer cannot be performed, check the following items and take action.
If the above action does not solve the problem, perform the module communication test to check for hardware failure. (
Page 284 Module communication test)
*1 The buffer memory address is for when the network type of the RJ71EN71 or the RnENCPU (network part) is set to "Ethernet" and the
P1 connector is used.
When using the P2 connector or setting the network type to "Q Compatible Ethernet", refer to the following.
Page 336 Buffer Memory
*2 If the connection of only the external device is closed due to cable disconnection, personal computer restart, or other reasons, reopen
the connection using the same port used before the error occurred. The E71 does not close a connection if it receives an Active open
request again from the external device with a different IP address or a port number.
Check item Action
Has the connection with the external device been opened? (Check 'Open
completion signal' (Un\G1900000 to Un\G1900007)
*1*2
• If the connection with the external device is not opened, perform the open
processing.
• If an error occurs, check and eliminate the error cause.
Did the external device send a command? Send a command to the Ethernet-equipped module from the external device.
Is the correct buffer memory address specified for the command? If the specified buffer memory address is incorrect, correct it and send the
command again.
Has data been set in the specified address of the random access buffer? If any data has not been set, write the data.
Has the write data been set in the external device? If any write data has not been set, set the data.
Was a response returned to the device that had sent the command? • If no response was returned, check if the correct IP address was specified
in the command. If not, correct the IP address and send the command
again.
• If a response was returned, check the end and error codes to correct the
error.
Is the communication method of the connection used for communication with
the external device is set to an item other than "Random Access Buffer" in the
"External Device Configuration" window of "Basic Settings"?
Correct the communication method setting if an item other than "Random
Access Buffer" is set. ( Page 244 External Device Configuration)