AVEVA™ Plant SCADA

MelsecQ - Communication Settings

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MelsecQ - Communication Settings

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Last UpdatedAug 04, 2025
2 minute read

To establish communication with a device, configure the Boards, Ports and I/O Devices settings in the Plant SCADA Studio's Topology activity. If you use the Express Communications Wizard to connect to a device, these settings will be automatically configured for you. However, if you need to manually configure these, use the information outlined below.

Boards

Field	Value
Board Type	Enter TCPIP.
Address	Enter 0.
I/O Port	Leave this field blank.
Interrupt	Leave this field blank.
Special Options	This field is not used.

Ports

For details about initializing the port, see MelsecQ - Hints and Tips.

Field	Value
Port Number	Leave this field blank.
Baud Rate	Leave this field blank.
Data Bits	Leave this field blank.
Stop Bits	Leave this field blank.
Parity	This field is not used.
Special Options	Enter the AJ71QE71 Ethernet module's TCP/IP address of the controller. See "I/O Device Address" below for details about this option.

I/O Devices

For details about initializing the I/O Device, see MelsecQ - Hints and Tips.

Field	Value
I/O Device Address	The CPU number (0-64 or 255). You can specify the CPU monitoring time using the optional parameter "/Tt" after the CPU number. It should be possible to specify the network number (0-239 or 255) by using optional parameter "/Nn" after the CPU number (only useful for MELSECNET/10 PLC networks). Finally you can specify the ASCII Mode for data exchange by using optional parameter /A (the default is binary mode). The address format is: a [/Tt] [/Nn] [/Pp OR /Qq OR /Ss] [/A] Where: a = CPU number 0 to 64 or 255 in decimal t = CPU monitoring time parameter (units 250 ms). The default is 10. n = Network number 0 to 239 or 255 in decimal. The default network number is 0. p = PLC number, default is 0 for control PLC s = System CPU 1 - Control System CPU 2 - Standby System CPU 3 - System A CPU 4 - System B CPU q = External device ID for multidrop Q mode C24 devices. /P, /Q and /S parameters are mutually exclusive. The precedence of them is /P > /Q > /S. Note: An in-depth description of the Network and CPU monitoring policy can be found in section 10.1 of the "MELSEC Q series Programmable Controller User's Manual - QnA Ethernet Interface Module type AJ71QE71(B5) - A1SJ71QE71-B2 - A1SJ71QE71-B5". Manual number IB (NA) 66661-C
I/O Device Protocol	Enter MELSECQ.

Field

Value

I/O Device Address

The CPU number (0-64 or 255). You can specify the CPU monitoring time using the optional parameter "/Tt" after the CPU number. It should be possible to specify the network number (0-239 or 255) by using optional parameter "/Nn" after the CPU number (only useful for MELSECNET/10 PLC networks). Finally you can specify the ASCII Mode for data exchange by using optional parameter /A (the default is binary mode).

The address format is:

a [/Tt] [/Nn] [/Pp OR /Qq OR /Ss] [/A]

Where:

a = CPU number 0 to 64 or 255 in decimal

t = CPU monitoring time parameter (units 250 ms). The default is 10.

n = Network number 0 to 239 or 255 in decimal. The default network number is 0.

p = PLC number, default is 0 for control PLC

s = System CPU

1 - Control System CPU

2 - Standby System CPU

3 - System A CPU

4 - System B CPU

q = External device ID for multidrop Q mode C24 devices.

/P, /Q and /S parameters are mutually exclusive. The precedence of them is /P > /Q > /S.

Note: An in-depth description of the Network and CPU monitoring policy can be found in section 10.1 of the "MELSEC Q series Programmable Controller User's Manual - QnA Ethernet Interface Module type AJ71QE71(B5) - A1SJ71QE71-B2 - A1SJ71QE71-B5". Manual number IB (NA) 66661-C

I/O Device Protocol

Enter MELSECQ.

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