Mask does not always see updates from Excel DDE link Options

[Kitt]

Greetings,
I'm getting intermittant problems with DataDisplay5 (ver 5.02.002) where my mask file does not see updates from an Excel spread sheet. The area I'm having problems with is a range of text cells in the spread sheet. I cannot reliably recreate the issue, but when it occurs it invariably seems to miss a cell changing from text to blanks. I have attached a screen shot  datawindowbefore.jpg ( 96.58K ) Number of downloads: 7
where the zone defined at the bottom of the display still retains some text that has since been changed to spaces. The next attachment  excel_page.jpg ( 61.87K ) Number of downloads: 4
shows what the text actually looks like in the Excel spreadsheet. When I edit that zone in the mask file  DDE_Link.jpg ( 35.24K ) Number of downloads: 6
, make no changes but click OK. The Mask file shows the correct information  datawindowafter.jpg ( 93.52K ) Number of downloads: 2
.

The Excel spreadsheet is a shared workbook  ShareWorkbook.jpg ( 34.54K ) Number of downloads: 4
. For the most part, I can make changes to the Excel spreadsheet and within 5 minutes I do see the correct updates in the mask file. But every now and then that zone in the mask file retains old data and I have to manually update it.

Any help would be appreciated.

[Scott McDowell]

Hi Kitt,

Since you're using a shared workbook, do you see any correlation between when someone updates the workbook from another PC and when the DDE updates are not sent? I wonder if it has something to do with the sharing of the file.

You could take the brute force approach and force the links to refresh or even reconnect the links on a timed basis. If you go to Setup > Options, there are two places you can make changes that may affect broken links.

1. On the General tab there is a "Force DDE Updates" option that you can select. This would make DataDisplay manually request values from Excel at a regular interval.
2. On the Miscellaneous tab there is a check box for "Automatically Refresh Links" option. Using this setting will cause DataDisplay to establish the DDE link with Excel at a regular interval. This is a little more "forceful" than simply asking for an update on an existing link.

I would start with forcing updates first and then try refreshing links if that doesn't help.

Please let me know if either of these settings help or if you can identify a particular set of steps that you can use to break the link between Excel and DataDisplay. Note that something as simple as restarting Excel on the computer where you're using DataDisplay will break your DDE links. However, if you just leave the software running and the updates appear in Excel then I would expect the DDE updates to be sent to DataDisplay reliably.

[Scott McDowell]

I had another thought after I posted my last message. If the cells are updated with a single character, such as a period, rather than blanking the cell, does the problem go away? No other customers have reported any issues with blank cells but I wonder if Excel is failing to send updates when a cell is emptied. This might explain why requesting the data again from DataDisplay refreshes the data.

[Kitt]

I had another thought after I posted my last message. If the cells are updated with a single character, such as a period, rather than blanking the cell, does the problem go away? No other customers have reported any issues with blank cells but I wonder if Excel is failing to send updates when a cell is emptied. This might explain why requesting the data again from DataDisplay refreshes the data.

Hi Scott,
Thanks very much for the reply. I am going to try the forced updates and see if that helps. Unfortunately when I try different tests, they always seem to work. I tried periods and that works, but then spaces work as well when I am watching. . . .

The Excel spreadsheet is on a network drive that was recently moved to a NetApps appliance. Unfortunately this mask file is also new so I don't know if it was failing to update on the old network drive as well. I will continue to keep an eye on it.

Thanks again.

[Scott McDowell]

Please follow up on this forum thread if you continue to experience issues. I expect that at least one of the above suggestions will allow you to work around the issue. However, I prefer to figure out the cause of an issue like this one rather than addressing the symptom. Thanks!