Mitsubishi A(1S)J71E71N Connection Guide for UDP

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The A(1S)J71E71N Ethernet module provides an Ethernet communication link to a Mitsubishi A-Series PLC Device. Fernhill SCADA can use this module to monitor and control a Mitsubishi A-Series PLC Device.

The information in this guide applies to a range of Mitsubishi Melsec A-Series Ethernet modules:

AJ71E71N-B5T10Base-5 & 10Base-T
A1SJ71E71N-B5T10Base-5 & 10Base-T

The rest of this article uses the name A(1S)J71E71N to refer to any of the above modules.

This guide shows you how to set up a A(1S)J71E71N Ethernet module to use MC Protocol over UDP.

Using the A(1S)J71E71N Ethernet Module

To connect Fernhill SCADA to an A(1S)J71E71N Ethernet module you will need to first configure the module. The A(1S)J71E71N Ethernet module configuration consists of:

Recommended Switch Settings

The module has an Operating Mode switch and Communication Exchange switches. The Operating Mode switch should be set to 0 (Online). The Communication Exchange switches should be set to these positions:

SwitchDescriptionRecommended setting
SW1Line processing during TCP timeout errorOff (close the circuit)
SW2Data code settingOff (binary mode)
SW3Automatic startup modeOff (Runs following Y19)
SW4Not usedOff
SW5Not usedOff
SW6Not usedOff
SW7CPU Exchange settingOn (writing approved)
SW8Initial timingOff (quick start)

Recommended Configuration

The A(1S)J71E71N Ethernet module is configured by writing values to the buffer memory of the Ethernet module. As a minimum you need to set values for the IP Address, and values for each Open Connection.

IP Address Setting:

Setting NameBuffer Memory addressRecommended Value
IP Address0 to 1IP Address of the PLC

Recommended Open Connection Settings

Setting NameBuffer Memory addressRecommended Value
Fixed buffer16 to 23 bit 01 - Receive
Protocol16 to 23 bit 81 - UDP
Open system16 to 23 bits 14-1500 - Active Open
Local station port no.24, 31, 38, 45, 52, 59, 66, 731281 (501h)
Destination IP address25-26, 32-33, 39-40, 46-47, 53-54, 60-61, 67-68, 74-754294967295 (FFFFFFFFh) -
Destination port no.27, 34, 41, 48, 55, 62, 69, 7665535 (FFFFh) - Any

You can configure the A(1S)J71E71N Ethernet module using a PLC program. The PLC program writes the appropriate values to the buffer memory of the module. The program will also need to interact with the I/O signals of the A(1S)J71E71N Ethernet module to successfully initialize it.

This example code shows the minimum steps to configure the A(1S)J71E71N Ethernet module using an A-Series PLC program. The program configures the IP Address to, and two open UDP ports at 1280 (500h) and 1281 (501h). Both UDP ports will allow any inbound address. This example writes 8003h to buffer address 1F0h, which allows the ethernet module to communicate even if the host PLC is in STOP mode. This is useful if you want to configure the PLC via the ethernet network from GX Developer.

The program assumes the A(1S)J71E71N Ethernet module is fitted to slot 0 (zero) of the main PLC rack.

|                                                   |
| M9038            *<IP Addr           |
+--| |------+-----------[DTOP H0 K0 H0C0A80117 K1]--+
|           |                                       |
|           |      *<Start the module               |
|           +----------------------------[SET Y19]--+
|                                                   |
|                                                   |
|  Y19             *<Allow access during stop       |
+--| |-----------------------[TO H0 H1F0 H8003 K1]--+
|                                                   |
|                                                   |
|  X10  Y19        *<Conn 1: UDP Port 1280 (500h)   |
+--|/|--| |--+----------------[TOP H0 K16 H101 K1]--+
|            |                                      |
|            +----------------[TOP H0 K24 H500 K1]--+
|            |                                      |
|            +---------[DTOP H0 K25 H0FFFFFFFF K1]--+
|            |                                      |
|            +--------------[TOP H0 K27 H0FFFF K1]--+
|            |                                      |
|            +----------------------------[SET Y8]--+
|                                                   |
|                                                   |
|  X11  Y19        *<Conn 2: UDP Port 1281 (501h)   |
+--|/|--| |--+----------------[TOP H0 K17 H101 K1]--+
|            |                                      |
|            +----------------[TOP H0 K31 H501 K1]--+
|            |                                      |
|            +---------[DTOP H0 K32 H0FFFFFFFF K1]--+
|            |                                      |
|            +--------------[TOP H0 K33 H0FFFF K1]--+
|            |                                      |
|            +----------------------------[SET Y9]--+
|                                                   |
|                                                   |

If for security reasons you wish to restrict the computers that can connect to the PLC you can set a specific destination IP address. For example, if you were to write H0C0A80101 to buffer address 25, then connection 1 would only accept messages from

For more information refer to A(1S)J71E71N User Manual.

Fernhill SCADA Configuration

The easiest way to configure Fernhill SCADA is to use the Mitsubishi Melsec UDP Autodetect Wizard. Based on the options you select the wizard will try different IP Addresses and Port numbers until the module is found. If a module is found you will be given an option to automatically create the correct configuration to communicate with the module.

If the autodetect wizard is unsuitable you can configure Fernhill SCADA manually:

Manual Configuration

To communicate with the A(1S)J71E71N Ethernet module configured as in the previous example:

  1. Create a Mitsubishi Melsec UDP Channel tag.
  2. Set the Host and Port configuration properties from this table:

    Host192.168.1.23The IP address of the A(1S)J71E71N Ethernet module
    Port1281The port number of Connection 2 in the A(1S)J71E71N Ethernet module
  3. Create a Mitsubishi Melsec PLC Tag and associate it with the channel just created.

Further Information

Mitsubishi Melsec UDP channel

To learn about Mitsubishi Melsec UDP communication channels.

Mitsubishi Melsec TCP Autodetect Wizard

To learn about automatically detecting Mitsubishi PLC Devices using TCP/IP.

Mitsubishi Melsec UDP Autodetect Wizard

To learn about automatically detecting Mitsubishi PLC Devices using UDP.

Mitsubishi Melsec Driver

For information about the Mitsubishi Melsec Driver.


For the meaning of terms used in Fernhill SCADA.