I seem to remember an example on the early days of PI DataLink for Excel Services that allowed you to send manual data entered on the webpage directly to the PI Server, I'll check to see if I can find it or if it helps as a reference.
My bad... the example I remember was on how to use the input of parameters into the Excel Services to do some calculation in the Web Spreedsheet.
I did found another example on how to send Values to the PI Server via InfoPath, which could work for you.
I'll do another search on Excel Services + user-defined functions.
The only thing that I found that could help you out is this link.
Technollogy wise you should be able to create your own User Defined Function that has access to the PI SDK dll's methods, so you may pretty much send the data in that way.
In case that fails you can create an Excel UDF that access a web service, you could give a try to the PI Web Service Product and use it to send data to the PI Server too!
In anyway, there could be a lot of solutions to this particular problem and the choices would reside in which one you are more confortable with!
This is a popular question. The thing is, EWA does not really enable manual entry from the web, the way that DataLink does using PIPutVal macro in Excel. For one, EWA does not allow you to enter data in cells, and there is no way to trigger a write operation when editing is complete. Interestingly, some of these capabilities are offered in Excel Services 2010, so we may consider how to leverage this functionality in future.
That said, I assume the real question is "Is there any way to write manual entry data to the PI Server through SharePoint?". It turns out there are a couple good ways. First, Andreas has a nice blog post which describes using the Data View web part. Second, we have a whitepaper in the Library on using InfoPath to do manual entry to PI. This could easily be extended to using InfoPath Forms Services in MOSS. The beauty of both these approaches is that the user only needs a browser to do manual entry.
Jay Lakumb, PM, Office Integration