I’m trending two tags side by side. The history is stored on tag change, and the polling engine scans one of them every 4 hours, and the other every 15 minutes. The dataset that is generated by this function always has the first column for timestamp, and the other two columns for the tag values.
So, the function always generates a dataset that has a timestamp that is every fifteen minutes, and fills in the corrosponding correct value for the first tag that gets updated every fifteen minutes, and fills in whatever the last good read was for the second tag:
Looking at the chart above, we see that the second tag has a lot of data filled in for the timestamps. This isn’t real data. Is there any way to make that dataset have an empty cell for the values for the second tag if there isn’t a real time-stamp?
Here’s the query I’m running:
tagList = [ '[default]Compressor Stations/WestWater Compressor Station/WEST WATER COMPRESSOR STATION/SUCTION STATIC PRESSURE', '[default]Orifice Meters/Duck/DUCK CREEK 13-28/GAS FLOW RATE'] dataSet = system.tag.queryTagHistory(paths = tagList, startDate = startDate, endDate = endDate, returnSize = -1, returnFormat = "Wide")