No Procedure - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

No procedure

The following figure shows the send processing for the fixed buffer No.1 area corresponding to the connection No.1.
'Initial status' (Un\G1900024.0)
'Open completion signal
(connection No.1)'
(Un\G1900000.0)
BUFSND instruction
BUFSND instruction completion
device
BUFSND instruction completion
device +1
 Normal completion of the initial processing is checked. ('Initial status' (Un\G1900024.0): On)
 A connection is established between the external device and the RJ71EN71 or the RnENCPU (network part), and normal completion of the connection No.1
open processings is checked. ( Page 378 TCP/IP Communications, UDP/IP Communications)
 The BUFSND instruction is executed. (Sends data)
 The data length amount of send data in the fixed buffer No.1 area is sent to the external device.
 When a response is received from the external device, the RJ71EN71 or the RnENCPU (network part) finishes data send. If the data send completes
abnormally, execute the BUFSND instruction again and start the send processing.
During UDP/IP communications, if the internal processing of the RJ71EN71 and the RnENCPU (network part)
completed normally, the data send processing may end normally even if the communication line between the
CPU module and external device is disconnected because of a connection cable disconnection or other
causes. Thus, providing a communication procedure and sending/receiving data is recommended.
1 FUNCTIONS
72
1.5 Communications Using the Fixed Buffer
Initial processing Open processing
Ò
Ó
Sending data
Ô
ACK
Sending data (TCP only)
Õ
Ö
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