ONLYRAW
The ONLYRAW modifier retrieves only the raw stored samples. It does not add interpolated or lab sampled values at the beginning of each interval during calculated retrieval such as average or minimum or maximum.
Normally, a data query for minimum value will interpolate a value at the start of each interval and use that together with any raw samples to determine the minimum value in the interval. Interpolation is necessary because some intervals may not have any raw samples stored.
- Example
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Import this data to demonstrate the behavior of the ONLYRAW query modifier.
[Tags] Tagname,DataType,HiEngineeringUnits,LoEngineeringUnits RAMPUP,SingleFloat,100,0 [Data] Tagname,TimeStamp,Value,DataQuality RAMPUP,06-Aug-2012 9:01:00.000,1,Good RAMPUP,06-Aug-2012 9:02:00.000,2,Good RAMPUP,06-Aug-2012 9:03:00.000,3,Good RAMPUP,06-Aug-2012 9:04:00.000,4,Good RAMPUP,06-Aug-2012 9:05:00.000,5,Good RAMPUP,06-Aug-2012 9:06:00.000,6,Good
When you query the minimum without any modifier, you see that the minimum value may not be one of the stored values.
set starttime='06-Aug-2012 09:02:30',endtime='06-Aug-2012 09:05:30' select timestamp,value,quality from ihrawdata where tagname = RAMPUP and samplingmode=Calculated and CalculationMode=minimum and numberofsamples=3
Time Stamp Value Quality 8/6/2012 09:03:30 2.500000000000 100.0000000 8/6/2012 09:04:30 3.500000000000 100.0000000 8/6/2012 09:05:30 4,500000000000 100.0000000 set starttime='06-Aug-2012 09:02:30',endtime='06-Aug-2012 09:05:30' select timestamp,value,quality from ihrawdata where tagname = RAMPUP and samplingmode=Calculated and CalculationMode=minimum and numberofsamples=3 and criteriastring='#onlyraw'
Time Stamp Value Quality 8/6/2012 09:03:30 3.000000000000 100.0000000 8/6/2012 09:04:30 4.000000000000 100.0000000 8/6/2012 09:05:30 5.000000000000 100.0000000 - Anticipated Usage
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Use the ONLYRAW modifier to query the minimum and maximum values of stored data samples, similar to the RawAverage Calculation mode. A minimum or maximum of raw samples is more like doing a MIN() or MAX () in an Excel spreadsheet. Realize that if you use the ONLYRAW modifier, there may be intervals with no raw samples. The ONLYRAW modifier is useful for Calculation modes and not the Sampling modes.