I am working on a symbol for a customer and the requirements call for the use of the TimeSeries data shape and the use of the ModePlotValues data query mode. I am setting an appropriate number of intervals for the symbol and plotting the resulting data on a graph.
The problem I have is that the shape of the resulting data is not what I was expecting. I am comparing a plot of the data returned by the onDataUpdate event with the standard PI Vision trend (I know this uses the Trend data shape but still I would have thought the general shape of the data would be the same) and also the "Plot" feature in PI System Explorer with the same number of intervals specified for the same time period.
As you can see below, the PI Vision trend and the PI System Explorer trend both show the same general shape however the data plotted from the PI Vision internals seems to stick to flat lines and then flick between step intervals (I checked the underlying tag and step is set to off)... So I'm wondering if there are any parameters other than Intervals which might control the shape or the sampling / interpolating algorithm that ModePlotValues returns? I've not yet tried plotting what comes out of the WebAPI directly however I would presume that it just goes to the AFSDK and calls the same method that get called by PI System Explorer? Any help or insight would be greatly appreciated.