As the name suggests this validation rule provides the facility to check the rate of continuous change (rise/fall) within a specified time period or span. The configuration part is almost similar to that of Rate of Change with one exception i.e. giving a timespan as shown below.
<validationRuleSet validationRuleSetId="validationROCTimeSpantest1896" timeZone="GMT"> <rateOfChangeTimeSpan> <rateofRiseFallDifferent> <rateOfRise constantLimit="1.6667E-05"/> <rateOfFall constantLimit="-1.6667E-05"/> </rateofRiseFallDifferent> <timeSpan unit="minute" multiplier="60"/> </rateOfChangeTimeSpan> <timeSeriesSet> <moduleInstanceId>Validation-import</moduleInstanceId> <valueType>scalar</valueType> <parameterId>Q.m</parameterId> <locationSetId>Meteo Stations</locationSetId> <timeSeriesType>external historical</timeSeriesType> <timeStep unit="hour"/> <readWriteMode>add originals</readWriteMode> </timeSeriesSet> </validationRuleSet>
Example
For this example, we take the rate of change (rise or fall of 0.1/hr) and timespan of 4 hr.
Looking at the figure above, the rate of change between Pnt0 and Pnt1 is more than Pnt1 and Pnt2. For a given validation rule, the rate of rise between Pnt0 and Pnt1 is violated and hence Pnt1 will be marked as Unreliaable point.
However the rate of rise between Pnt1 and Pnt2 is not violated and hence Pnt2 should be marked a valid point. However Looking at the rising trend, the rate of rise between Pnt0 and Pnt2 is violated. Hence wrt Pnt0, Pnt2 should be marked a unreliable.
This functionality is captured under the functionality of Rate of Change within given TimeSpan.
Under normal circumtance Pnt1 will be marked as Unreliable point, and Pnt2 will be marked as Reliable point. But as long as the time elapsed between Pnt0 and Pnt2 is not exceeded the given timespan, Pnt2 will be compared with the Pnt0 instead of Pnt1. In such a situation Pnt2 will also be marked as Unreliable point.
Now we move further to Pnt3, the rate of rise between Pnt2 and Pnt3 is not violated, however compared to the Pnt0, Pnt3 will be violating rate of change because it also falls under the timespan of 4 hrs.