1.6 Communications Using The Random Access Buffer; Setting Procedure - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

1.6
Communications Using the Random Access
Buffer
With communications using the random access buffer, data can be freely read and written between any external device
(excluding Ethernet-equipped module) and the RJ71EN71 or the RnENCPU (network part). The external device does not
need to be fixed. The random access buffer is used as the common buffer area for external devices connected to the
Ethernet.
Writing
External
device
Reading
Writing
External
device Reading
Precautions
The CPU module (CPU part for the RnENCPU) cannot exchange data with the random access buffer.

Setting procedure

Set "External Device Configuration" under "Basic Settings". ( Page 244 External Device Configuration)
1.
Select the external device to be connected in "Module List" and drag it to "List of devices" or "Device map area".
External device name
UDP Connection Module
Active Connection Module
Unpassive Connection Module
Fullpassive Connection Module
2.
Set "Communication Method" for external device to "Random Access Buffer".
3.
Set the IP address of the external device.
4.
Set the other parameters required for communication in the connection. ( Page 244 External Device Configuration)
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1.6 Communications Using the Random Access Buffer

RJ71EN71 or RnENCPU
(network part)
Writing
Random
Reading
access
buffer
Writing
Reading
Writing Reading
External
device
Description
Select to communicate with the external device using UDP/IP
Select to perform the open processing to the external device from the Ethernet-equipped module (Active open)
and communicate using TCP/IP.
Select to receive the open processing from an unspecified external device (Unpassive open) and communicate
using TCP/IP.
Select to receive the open processing from the specified external device (Fullpassive open) and communicate
using TCP/IP.
External
device
External
device