Suppose you are filling a tank. The first measurement reads a level of 100 gallons at 12:15 and the second measurement reads a level of 105 gallons at 12:16. When Proficy Portal plots this data, it assumes a constant flow rate of 5 gallons per minute so that placing the time cursor at 12:15:30 yields a value of 102.5 gallons.
The interpolation method used is configured with a property called the Retrieve Mode. For example, suppose a time chart shows data from the last eight hours and has a data point interval of half an hour. If the Retrieve Mode is Average, then the chart shows the average values in each 30-minute interval. However, if you change the Retrieve Mode to Maximum, the chart shows the maximum values in each 30-minute interval.
Not all applications lend themselves to interpolation. If your application treats each data value collected as a discrete point, select Raw by Number or Raw by Time as the Retrieve Mode.