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I have been to the OPC Programmers Connection and the OPC Foundation, but what I can't find is any concrete examples of DDE's limitations. Are there
any benchmarks to demonstrate within an order of magnitude what both are capable of, locally and over a network. Obviously in these areas, Your
Mileage May Vary, but at least an overview of performance ability would be good.
I have programmers here telling me that they can get 20 ms updates via DDE with up to 30 points per second "and that's good enough" sort of thing, and what I keep telling them is that the reason OPC was invented was so that we could do hundreds or thousands of points per second, and so on.
Unfortunately, I'm completely unarmed with any documentation on the subject, and all I can do is present my own experience that DDE sucks, from my
experience using WonderWare. Faced with a half dozen programmers all crying to go ahead with the easy way out (DDE) for all their drivers from now on, can I stop them, or at least give them pause to think about DDE's limits somehow? It seems silly to me to be implementing DDE servers in the year 2000.
Warren
any benchmarks to demonstrate within an order of magnitude what both are capable of, locally and over a network. Obviously in these areas, Your
Mileage May Vary, but at least an overview of performance ability would be good.
I have programmers here telling me that they can get 20 ms updates via DDE with up to 30 points per second "and that's good enough" sort of thing, and what I keep telling them is that the reason OPC was invented was so that we could do hundreds or thousands of points per second, and so on.
Unfortunately, I'm completely unarmed with any documentation on the subject, and all I can do is present my own experience that DDE sucks, from my
experience using WonderWare. Faced with a half dozen programmers all crying to go ahead with the easy way out (DDE) for all their drivers from now on, can I stop them, or at least give them pause to think about DDE's limits somehow? It seems silly to me to be implementing DDE servers in the year 2000.
Warren