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IOServer DDE interface

Application Name

Microsoft has dropped support for DDE since VISTA.
Windows XP still supports DDE.
IOSDDE.exe does not exist. IOSDDE is DDE service name for IOServer.

Topic Name

Any Topic Name will be accepted as valid. Should allocate a topic for each device.

Update Rate

The initial update rate of all Topics is IOServer Preferences->DDE Settings->Update Rate. The update of each Topic can be individually set by writing to IOSDDE|TOPIC!UPDATERATE. e.g. Poking 100 to IOSDDE|RTU12!UPDATERATE will set the update rate for Topic "RTU12" to 100ms.

Using IOServer with Excel

To display a 10x10 array from the Modbus Device 'Master'.

1. Select a 10 by 10 area.

2. Type in


3. Press Ctrl-Shift-Enter


Example of a function to write the value at worksheet OPC.A4 to "Master.40001"

Sub TagWrite()
Dim rangeToPoke
Dim channel
channel = Application.DDEInitiate("IOSDDE", "Group")
Set valueToPoke = Worksheets("OPC").Range("A4")
Application.DDEPoke channel, "Master.40001", valueToPoke
Application.DDETerminate channel
End Sub

Using NetDDE from Excel in Windows 2000/XP/NT4

Server Configuration

1. Run %SystemRoot%System32\ddeshare.exe on the computer on which IOServer is running.

2. Add a share in the Shares.DDE Shares.


3. Set Trusted Share Properties in Shares.Trusted Shares.


4. Load mbtcp.io into IOServer.

Client Configuration

Enter the following into a cell in Excel

Where Gateway is the DDE Server Machine name


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Last updated: Thu, 16 Jun 2022 08:01:55 GMT