Mitsubishi Electric MELSEC-L SERIES Basic User Manual page 129

(2) No procedure
The following is the receive process performed in the fixed buffer number 1 area for the connection number 1.
Initial process
Initial normal completion
signal X19
Open completion signal
(address: 5000 [b0])
H
BUFRCV instruction
BUFRCV instruction
completion device
BUFRCV instruction
completion device + 1
Fixed buffer reception status signal
(Address: 5005H [b0])
Confirm the normal completion of the initial process. (Initial normal completion signal (X19): ON)
1
Establish a connection between the E71 and the connected device and confirm the normal completion of the
2
open process of the connection number 1.
Receive data from the connected device.
3
• Fixed buffer reception status signal (address: 5005
Execute the BUFRCV instruction to read the receive data length and receive data from the fixed buffer
4
number 1.
• Fixed buffer reception status signal (address: 5005
End the receive process. If the data receive process is abnormally ended, execute the BUFRCV instruction
5
again to repeat the receive process.
● The items configured in the open setting become enabled when Open completion signal of an E71 is started up.
● When the buffer memory area that stores Fixed buffer reception status signal is turned off and on, execute the BUFRCV
instruction.
● When abnormal data is received, Fixed buffer reception status signal does not turn on. In addition, data is not stored in
the fixed buffer number 1 area.
Open process
1
2
CHAPTER 12 COMMUNICATIONS USING A FIXED BUFFER
Receiving data
ACK
(TCP only)
3
(b0)): ON
H
(b0)): OFF
H
4
5
1 scan
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