#### Peter Nachtwey

##### Member

In reality EVERYTHING HAS A DEAD TIME!!!!I please to excuse me, I have one stupid question:

Why do all your models include dead time? Do all your systems have transport delay (conveyors, pipelines, etc.)? What is the reason?

In most cases the dead time is so small it can be ignored.

That doesn't' look right because there is no dead time. What is the SSE ( sum of squared errors ) between the actual data and your estimated data? I always print that because it tells me how good my model is.Peter Nachtwey's "Hotrod.zip" example is approximated pretty well by the following function

W(s) = 3,77142857142857/ ((170,2864769*s+1)* (36,0195267*s+1)* (14,57362541*s+1)* (11,51468826*s+1))

This doesn't look right either. Again, would like to see the SSE.destination unknown example (post 36):

W(s) = 2,22 / ((91,225*s+1)* (21,3625*s+1))

(If I get data (not image) maybe I can improve the model.)

SSE is the sum of squared errors is more appropriate than other evaluation methods when testing for goodness of fit between a model and actual data.

My SOPDT program returns this for hotrod.txt

sse = 250.31414761879358

RMS error = 0.436

The open loop gain = 3.757 PV/%CO

Time constant 0 = 0.685 minutes

Time constant 1 = 2.849 minutes

Ambient PV = 77.840 in PV units

Dead time = 0.354

Time units are the same as provided in input file

The closed loop time constant = 0.285

The controller gain = 1.472 %CO/unit of error

The integrator time constant = 3.534 minutes

The derivative time constant = 0.552 minutes