Mitsubishi Electric MELSEC-L Series - Page 80

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(2) When "Do not wait for OPEN (Communications impossible at STOP time)" is
selected for the Ethernet operation setting
Executing the OPEN/CLOSE instructions is required on the E71 to make the E71 enter open/close wait status
before receiving an open/close request from the connected device. When the open process is normally
completed, data sending and receiving are enabled. For the OPEN/CLOSE instructions, refer to "DEDICATED
INSTRUCTIONS". ( Page 196, CHAPTER 15)
Ex.
Open/close processes for the connection number 1
*1 An open request (SYN) received after the normal completion of an initial process and before the E71 is in the OPEN
request wait status will cause an error, and the E71 sends a connection forced close (RST).
After parameter communications, check that the initial process of the E71 is normally completed.
(Initial normal completion signal (X19): ON)
Start the open process using the OPEN instruction. (Open request signal (address: 5002
H
(b0)): ON)
The E71 starts the open process upon receiving the open request (SYN) from the connected device. When the open
process is normally completed, Open completion signal (address: 5000
H
(b0)) turns on and data communications are
enabled.
The E71 starts the close process upon receiving the close request (FIN) from the connected device. When the close
process is completed, Open completion signal (address: 5000H (b0)) turns off and data communications are disabled.
Start the close process using the CLOSE instruction. (Open request signal: OFF)
1
2
3
5
4
ACK
Open status
Open allowed status (closed)
(Active open acceptance enabled)
Closed status
Initial normal completion
signal X19
OPEN instruction
OPEN instruction
completion device
OPEN instruction
completion device + 1
CLOSE instruction
CLOSE instruction
completion device
CLOSE instruction
completion device + 1
Open completion signal
(address: 5000
H)
Parameter
communication
completed
1 scan
1 scan
FINACKSYN
SYN + ACK FIN + ACK
Open request signal
(address: 5002
H)
Power-on
Open abnormal detection
signal X18
*1
Abnormally
ended
Abnormally ended
Abnormally
ended
1
2
3
4
5