How To Obtain Gain "K" Value From Root Locus Plot - Or Other Tool Needed? #1198

Hi,

yes, I am aware that the root locus varies the K value. What I am asking is once having plotted the root locus, how do you determine the value of K on the plot. For example, in the following plot, if I wanted to find out the value of K here, how would I determine it at that particular location? If I hover my mouse over the plot, the x and y values are highlighted on the upper-right hand corner. The value of K is not.

Referencing the general formula for calculating the gain at a particular location of the root locus, it appears that it consists of dividing the product of the pole vectors by the product of the zero vectors (absolute values). Is this not something that is trivial using matrix / vector mathematics? So, if you move / hover the mouse over a particular location of the root locus, being that it already has the locations / values of all of the zeros and poles, can it then automatically calculate the value of "K" (it automatically displays the x and y values - why not "K")?

If you click a location on the root locus plot, the gain at that point on the plot will show up at the top of the screen:

Oh, I see. You actually have to select it with the mouse. I did not do that. I thought merely hovering the mouse pointer over the plot would do the trick since when doing so, the x and y values appear on the right-hand corner - thus was expecting the same for the K value.

This fixes the issue.

Thank you very much for clearing this up.

Much appreciated!

Issue is rectified.