You may access everything in simlog through MATLAB base workspace. This documentation page includes some basic functions to access and plot the logged data: https://www.mathworks.com/help/physmod/simscape/ug/log-and-plot-simulation-data.html
To take it one step further, you can extract the time and value (in any reasonable unit you wish) of a simlog signal series, and use them as base workspace variables. Then you can "hold on" and plot several of them together.
Here is the doc page on the "series" of simlog data: https://www.mathworks.com/help/physmod/simscape/ref/simscape.logging.series.html
The "time" and "values" functions/methods of the series will give you the access you need.
Some pseudo-code:
% run some simulation first
t = time(simlog.motor.w.series); % all signal should have the same time stamps
v1 = values(simlog.motor.w.series,'rpm'); % specify unit
v2 = values(simlog.motor.v.series); % default unit
figure(1); clf;
hold on;
plot(t,v1);
plot(t,v2);
I believe you can also do
t = simlog.motor.w.series.time;
v1 = simlog.motor.w.series.values('rpm')
