Hello.
For record, here is the related piece of documentation:
opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...ite%20with%20RTD%20Server.html .
Ad 1. The feature is no less supported than anything else in the product. That is, it should work as designed, and if it doesn't, we will attempt to address it. The issue here is what *as designed* is. The functions in Excel are, well, functions. They are not supposed to have side effects, and consequently, Excel is basically free to evaluate (and re-evaluate) them at just about any time. The "topic write" feature of the RTD server does have an important side effect, and that's what in some way collides with the Excel. So, the feature should work, in the sense that every time Excel evaluates the RTD function that specifies "toipc write", the OPC write should occur. Whether that is what you need or can live with, is up to you.
Ad 2. No, we are not planning any improvements in this area (because currently we do not know about any better way). If the "topic write" does not work the way you want, you can do the OPC writes with QuickOPC in a different way, though. You can use VBA and call QuickOPC methods to do the write. We have examples for that as well. To find them, 1) make sure you install QuickOPC including "COM development", and 2) under the product folder, look for ExamplesNet\VBA\Excel\UAReadAndWriteValue.xls.
Ad 3. Please be more specific. Are you asking about possibility to handle errors that occur during "toipc write" with RTD server yourself?
Best regards
