DDE links

[plcnewbie]

I have been making spreadsheets in Excel using the copy and paste of DDE links from RSLinx, so that I can follow the product path. Recently one of the sheets I made which has I/O points from 2 similar but seperate machines seems to have a bug.
When I open it now both links show the same data in other words it is only showing me the signal from one machine but on both links, while the other is not running or running.

I think this may have to do with the fact that I use 2 seperate laptops and therefor 2 seperate RSLinx? But I do save the sheets on my file under the main server which is accessable from both laptops. Would this just be that if I make the sheet in on one laptop and open it on another the path gets destroyed? Thats the only thing I can think of.

Thanks

 

[OkiePC]

I've had problems similar to yours. My solution was to put all the PLC references on a single worksheet that is hidden and protected. Then I created sheets in the same workbook that referenced the data in those cells. Doing that will let you organize your data for efficient communication to the PLCs, but your other sheets can format the information however you like. Because they're all in the same workbook, the references won't get fouled up when you move it to another PC or network drive, however, the path to the PLC will probably change, meaning you may have to recreate the raw data sheet. You can use search and replace to correct the path in the raw data cells "en' masse" to fix it after it's been moved. One other thing that will screw up your references is renaming worksheets. (Take a close look at the functions and formatting that occupy your cells when you paste a link from RSLinx.) I wound up keeping the file open and running on one PC that was connected to the PLC networks, and sharing it via the LAN to anyone who needed access. They could open it "read-only" and select the sheet they needed for monitoring or printing. It's been a few years back, but I think their data was only refreshed when they opened the file. I can't remember for sure. I just created a short-cut for each of them that would access this one file from their PCs.

 

[Andybr]

DDE does not care about the path to the PLC's. It is only concerned with the Topic which is set up in Linx. If you used the same Topic name on both of your laptops then this would result in the behaviour that you are seeing. You need to create 2 seperate topics in Linx for the two PLC's and edit the links in Excel so that each cell uses the correct topic.

 

[UncleBuck]

Do you open more than one Excel worksheet?
Ok, if you right click on the graphic communication in RSLinx corresponding to the PLC Config and creat a topic for machine 1. Do the same for Mach 2.
You are using two DDE logpoints for each topic.
Two separate Excel worksheets that have different topics and different Ecel file names.
Is this what you did? And if so, can you log both points to the DDE worksheets at the same time?

 

[yam785]

Check under the sheets!

I had a similar problem with Wonderware and Excel. We print the spreadsheets to use as audits. I mistakenly set it up where I was looking at the same sheet. I have a feeling if you are using more than one sheet, this is your problem. Let me know.

Hope this helps.

To work with PLCS and launch dirtbikes over nasty jumps in the same lifetime is almost as good as it gets!