Can OPC DA and OPC HDA interfaces run at the same time for the same set of tags for getting real time data and historical data respectively?
Roger is right, it is not recommended to have several sources writting into PI points. That being said, it is actually possible to run both interface simultaneously.
PI OPC HDA interface should be run interactively and just started up when required for data gaps. You need the DA and the HDA interfaces to have the same pointsource and location1 settings as well as the same scan classes etc. HDA will allow polled in scan class # 1 but the DA threw errors. You need to stipulate the time range you want history recovery for with the PI OPC HDA interface when a known data gap is determined. Via the ICU > OPCHDAint > Optional Parameters > check “History Recovery Only – time range” for the time period you need to recover data for.
The problem with having the ICU have more than one interface with the same pointsource and location1 settings is that it throws warning messages each time you load either of the interfaces. As a workaround you can configure HDA in ICU with different PS but manually change PS back in the .bat file.
No. A PI Point is linked to a single interface, so a single PI Point cannot be linked to both the OPC DA and HDA interfaces.
When you can choose, choose HDA over DA as you will have history recovery available.
I know my facts were only a partial fact, but i though, let's keep it simple. There is a lot you can do, but also a lot you should not..
Retrieving data ...