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1 FUNCTIONS
1.5 Communications Using the Fixed Buffer
External devices capable of data exchange
Data can be exchanged with the following external devices.
• Devices in Ethernet to which the RJ71EN71 is connected
• Devices in Ethernet to which the RnENCPU (network part) is connected
• Device connected via router
As the following figure shows, the external device for communication and the working application (for send/receive and
"Procedure Exist"/"No Procedure") are set in "External Device Configuration" under "Basic Settings" using each fixed buffer
(No.1 to No.16) to fix the external device for each buffer.
Pay attention to the following when changing the external device.
• During TCP/IP communications, the external device can be changed only when a connection is not established with the
external device (when the open completion signal is off).
• During UDP/IP communications, the external device can be changed regardless of the connection status with the external
device.
• When changing the external device, do not use the pairing open or alive check function.
Processing during data send/receive
■During data send
When the BUFSND instruction is executed, the RJ71EN71 and the RnENCPU (network part) send data from the
corresponding fixed buffer to the external device set in the specified connection.
■During data reception
If the data is being received from an external device set in the specified connection, the RJ71EN71 and the RnENCPU
(network part) process the reception.
If data is being received from an external device that is not set in the specified connection, the RJ71EN71 and the RnENCPU
(network part) will ignore the received data.
External device 1
External device 8
External device 28
Fixed buffer No.16
Fixed buffer No.2
Fixed buffer No.3
Fixed buffer No.1
For sending data to the external device 28
For receiving data from the external device 1
For receiving data from the external device 8
For sending data to the external device 1
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