I do 3D carving, and it's very important to know the job runtime before 
starting and while tuning, for various reasons.

The Properties time estimator is not useful, it just uses distance/feedrate.  
That doesn't take into account acceleration, which dominates the runtime in my 
case.  The actual runtime can be 3x-20x the time estimated there, depending on 
how deep and detailed it is, so it really says nothing.

I'm used to estimating under Mach3, which gives a 100% accurate time estimate 
which was wonderful.  It may take a few minutes to eval a large file. 100:1 is 
an acceptable eval time (100 min file evaluated inside 1 min).

I did have a thought "what if I give 100x the vel and accel, stepgens,  100x 
the Traj max vel/accel, divide the axis SCALEs by 100x, and use 100x for 
Feedrate Override?"  Then I could just disable the physical stepper drives, 
take the cycle time and mult by 100x. Actually that won't stress the step times 
weirdly because their scales are divided by 100x.

But all I got was "Joint Following Error" and couldn't move anything, even in 
manual jog.  Not sure why, with the scale kicked down 100x, a max velocity 100x 
greater will just run steps out at the same max speed.  But apparently I broke 
something.  I do use a 7i92 card with a PLL so there's that.  I did increase 
MAX_ERROR by 100x but no luck there.

Is this experiment a dead end?  Why did it break, and is there any way to make 
my concept work?

Is there a better way, like disconnecting EMCMOT from the stepgen and having it 
tally the time consumed without actually spending the time to do anything?


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