Motor Acceleration between Master & Slave

[SparWeb]

Hello,

I've been enjoying my CNC router table since getting it several months ago. The holidays have given me time to try some more ambitious projects, and get tighter tolerances on parts. I knew this is when limitations or problems would show up, but no disasters so far.

Anybody still using Mach3?

I bought a CNC router! It's old! No it's not that bad, but it's a DIY project that the guy has picked at for almost 20 years. Still works, and tonight I have cut wood by jogging the cutter, just trying it out. Learning as I go. The CNC software is installed on a geriatric Windows XP computer...

canadianhobbymetalworkers.com

It's a CNC gantry router (42" x 30") with stepper motors. The gantry moves on belt-driven rack and-pinion, pretty typical.

I have run into a little mystery and I'd like to run it by the wise members here, before I change a setting I don't understand.
I set out to correct a scaling error, and I seem to have found a racking error at the same time. No big surprise, but as I investigated further, I found that the two motors driving the Y-axis have different parameters set. These 2 stepper motors are slaved together and I would assume that they should operate identically. Instead I find that only the velocity settings are the same. They are set to different accelerations. I don't understand why this would be.

Master:
Steps 1736.237
Velocity: 150 in/min
Accel: 30.669776 in/sec/sec
G's: 0.07944
Step Pulse: 2 microsec

Slave:
Steps 1736.237
Velocity: 150 in/min
Accel: 65.0 in/sec/sec
G's: 0.16836
Step Pulse: 2 microsec

Should I change them to match, or is there a reason for the two settings to be different?

 

[SparWeb]

Photos from Mach 3 so that you can see what I am seeing...

 

[DavidR8]

I have a slaved motor on the Y axis of my router. You definitely want them to be the same. Also check the DIP switches on the drivers to make sure they are set the same.

 

[phaxtris]

i also have a slave on my router table, the parameters are set the same for both, drivers should also be set the same (the dip switches as @David_R8 mentioned)

 

[SparWeb]

OK fixed that.
Found another problem: The slave-motor's A-axis prox-sensor was 3/16" back from the stop compared to its counterpart Y-axis sensor.
I found this problem because re-referencing the Y-axis to home didn't zero-out the A-axis and its motor kept turning. Loud noises!
Shifted the prox sensor forward until the sensor's little light came on. Now when I reference the Y-axis, the A-axis comes into Home at the same time.
I had never noticed this wasn't happening before!

I'll do some more test measurements to see if the gantry has come back in line, yet.

Thank you guys!