Mitsubishi Electric MELSEC-L SERIES Basic User Manual page 197

(3) If a response message cannot be received from the connected device
If a response message cannot be received from the connected device (or if an error has been detected) using the
alive check function, the following processes are performed.
• The corresponding connection will be forcibly closed. (The line is disconnected.) Open the connection using
a user program again.
• Open completion signal is turned off, and the error code (C035
area.
Ex.
Assuming that the values
check at the timing shown in the figure below (an example of alive check using the PING command).
Open completion signal
(address: 5000 )
H
The last
communications
Starting interval
timer for alive check
of the target device
*1 The values of the number of retries and timers can be changed in the initial setting. (
*1
are set so that the number of retries may be three, the E71 performs an alive
E71
Alive check
Alive check
(1st time)
Interval timer Interval timer
value for alive value for alive
check of the check of the
target device target device
CHAPTER 14 OTHER FUNCTIONS
) is stored in the open error code storage
H
Connection
forced close
(error code: C035
Alive check Alive check
RST sending
resent resent
(TCP only)
(2nd time) (3rd time)
Interval timer Interval timer
value for alive value for alive
check of the check of the
target device target device
Page 311, Appendix 4.1)
)
H
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