Control Systems: HP prime app, now with frequency, time domain and root locus plots

[hata]

Hi Chandler

No, you can't specify the end points of the range, you specify the midpoint (= controller gain) AND you specify the relative range from a dropdown list (e.g. x 0.02 - x 50) - which gives you the endpoints of course.
In case you don't have a controller (only a process): select controller type 'P' (proportional) and enter the desired mid-point for the open loop gain range.
If the open loop gain (center point) is already baked in the process (transfer function) itself, than enter '1' as desired mid-point for open loop gain, or select controller type 'none'.
Note that the two last options in the dropdown list for open loop gain range allow you to enter one endpoint for the range - because the range lies completely to the left (x 0.01 - x 1) resp. to the right (x 1 - x 100) of this endpoint then.

Also note that there is not a fixed linear step involved between samples, but a factor by which the frequency of each sample is increased to calculate the frequency of the next sample: the samples form a geometric series. This makes more sense, because in the high frequency range you want this step to be greater than in the low frequency range. Compare with a Bode chart, which is logarithmic for the same reason.
You don't choose the factor yourself - it is calculated for you based on the number of samples you want (drop down menu) and the open loop gain range (drop down menu).

Hope this helps.
Regards