vba - How to determine when a value is stabilized -
i trying find way determine when value stabilized in excel. in case, temperature. have set of time-series data, timestamp , temperature. @ t=0, temperature begins rise @ rapid rate. when setpoint temperature approached, rate of rise decreases, until finally, stabilizes around setpoint. temperature tends overshoot , undershoot setpoint several degrees before stabilization.
how can have excel figure out when temperature "stable" around setpoint? example, delta t (sp-pv) <= 2. (delta t difference between set point sp , process variable pv)
i thinking possibly using time variable determine data set size (i.e. 5 minutes) , see if average delta t within time <= 2.
i not know how excel search through whole series though.
if @ difference between setpoint , value @ time 0, may mistake crossing "stabilized" point. need examine both estimated rate of change (tn - tn-1)/dt , current value.
stability going combination of "how fast signal still changing" , "how close i". isn't uncommon in real systems there fixed offset (steady state error) between setpoint , measurement no change happening in signal on time. typically corrected integrative term in control system.
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