# LTSpice constraints on plots

A have a circuit for which I have parameterized some of its resistors with the .STEP command. Consequently, I have many different graphs when I simulate the circuit. I would like to know if it was possible to put a constraint on the graphs that would tell the simulation which one can be plotted (like for example : V(vout) <= 100mV)?

• I don't believe there is. And what's more annoying is that there's no way to really know which plot corresponds to each element in the .STEP command. – squarewav May 8 '16 at 4:36

It is possible to differentiate the steps in LTspice by Right-Clicking on the waveform's label (in the waveform window) and then adding @x to the trace's expression, where x is the step's number. For example, for .step param x 1 5 2, plotting V(out)@1 will plot V(out) for the value x=1 (first step), V(out)@1 => x=3 (2nd step), and V(out)@3 => x=5 (3rd step).
Alternately, you can Righ-Click in the waveform window and then on Select steps, where you will be presented a more graphical option of plotting the steps.
As a side note, in case you have stepped points and you have used .MEAS commands, the log file will have results for each step. With the log file still opened, you have theoption to plot the results with Righ-Click, then choose Plot .step'ed .meas data.