Mitsubishi FX Serial Connection Guide

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To setup communications between Fernhill SCADA and an FX PLC, the FX PLC requires a communication module. The communication module needs to be one that supports the Computer Link protocol.

These communication modules are known to support the Computer Link protocol, and will work with Fernhill SCADA:

PLC RangeModule(s)
FX1NFX1N-232-BD, FX1N-485-BD
FX1SFX1N-232-BD, FX1N-485-BD
FX2NFX2N-232-BD, FX2N-485-BD, FX2NC-485ADP, FX2NC-232ADP
FX3UFX3U-232-BD, FX3U-232ADP, FX3U-485-BD, FX3U-485ADP
FX3GFX3G-232-BD, FX3U-232ADP, FX3G-485-BD, FX3U-485ADP
FX3SFX3G-232-BD, FX3U-232ADP, FX3G-485-BD, FX3U-485ADP

The rest of this article uses the name FX Serial Module to refer to any of the above modules.

Connection Cables

These modules support RS-232 communications:

The serial port on a PC is usually a 9 pin D-subminiature connector. To connect one of these modules to a PC, a connection cable with this wiring is required:

FX RS-232
DE-09 Female Layout
DE-09 Female Layout
DSR + DCD6 + 14DTR

Note: All other pins not shown in the above diagram have no connection.

Configuring Serial Communications

Setting up a serial communication link can be difficult because of the wide variety of communication options. For example:

For Fernhill SCADA to communicate with an FX Serial Module, both need use the same communication options. There are a two main ways to achieve this:

Manual Configuration

The FX Serial Module can be configured using one of two methods:

Note: Not all PLC ranges support configuration through parameters

Fernhill SCADA is configured using properties of the Channel and PLC tags:

Using PLC Code to Setup FX Serial Modules

A typical PLC program to setup an FX serial module is:

|                                                   |
| M8002                     *<Setup CH1             |
+--| |------+--------------------[MOV H6882 D8120]--+
|           |                                       |
|           |               *<Station Address       |
|           +-----------------------[MOV H0 D8121]--+
|                                                   |

Note: The above program configures channel 1 to use the Computer Link protocol. The serial format is 9600 Baud, 7 data bits, 1 stop bit and Odd parity. The station address is 0 (zero).

These registers store the configuration parameters for the FX Serial Modules:

ParameterChannel 1Channel 2
Protocol and formatD8120D8420
Station addressD8121D8421

Some FX PLC types only support one serial port (Channel 1).

Example values for register D8120 or D8420 and the corresponding configuration in Fernhill SCADA:

Fernhill SCADA Mode StringD8120 or D8420
Baud=9600 Parity=O Stop=1 Data=7H6882
Baud=9600 Parity=E Stop=1 Data=7H6886
Baud=9600 Parity=E Stop=1 Data=8H6887
Baud=9600 Parity=E Stop=2 Data=8H688F
Baud=19200 Parity=O Stop=1 Data=7H6892
Baud=2400 Parity=O Stop=1 Data=7H6862

Further Information

Mitsubishi Melsec Serial Autodetect Wizard

For how to automatically configure Fernhill SCADA to communicate with a Mitsubishi serial communication module.

Mitsubishi Melsec serial channel

For information about Mitsubishi Melsec serial channel configuration.

Mitsubishi Melsec PLC Tag

For information about Mitsubishi Melsec device configuration.

Serial Communications

For background information on serial communications.

Mitsubishi Melsec Driver

For information about the Mitsubishi Melsec Driver.


For the meaning of terms used in Fernhill SCADA.