DDEPoke a value through RSLinx OEM to an address in my PLC using VBA

[Rusty_The_Kid]

I am running the VBA code:

RSIchan = DDEInitiate("RSLinx", "Topic_Name")
DDEPoke RSIchan, "Program:MainProgram.REC_Unlatch", Range("K3")
DDETerminate (RSIchan)

This code is taking the value in cell K3 (value of 1) and sending it to a relay contact in my PLC using the address "REC_Unlatch". It works fine. I would like to just send a 1 to my PLC, without having to reference a cell in Excel. Can this be done, and if so, how would I format the instruction?

Thanks in advance!

[Leith Ross]

Hello Rusty_The_Kid,

DDE (Dynamic Data Exchange) relies on shared memory objects. The 'conversation" between the client and server is conducted by Windows messages that describe the application, topic, and item. Since neither constants nor literal values are objects, no conversation can occur.

[Rusty_The_Kid]

Hi Leith, sounds like I need to always reference cell contents in such communications. Since my VBA code sends me into a new active workbook during my data-recorder loop when I want to send this "1" or "0" data back to the PLC, I suppose I can write a "0" and a "1" into a worksheet in the newly created workbook, then use those cells as objects to send back to the PLC as desired. Thanks for your help, I will work on that tomorrow.