Tuning the Machine

OK, now to get the OZO purring like it otter…

First I visited EMC Wiki and followed the latency test directions.

These directions are basically the same ones in the integrators manual, however there are a couple of new wizards mentioned on the Wiki page, that came out with release 2.2.2. I first ran the latency test the old fashioned way, and then the newer way by just typing latency-test into a terminal.

The results:

Old way reports 22,778 nS

New way jitter reports 20,020 nS

I decided that I would take an average 20,544 nS and round down to 21 uS

Now to figure out thread pitch, using the method described here I came up with:

X Pitch Count=5 Pitch=.200 in.

Y Pitch Count=5 Pitch=.200 in.

Z Pitch Count=8 Pitch=.125 in.

My motors are 1.8 degree per step 200 steps per revolution.

From the best  manual I could find, my stepper controller requires 15 uS step hold time, there is no timing information for the direction pin. So, rather then configure step time, step space, direction hold, direction setup times individually, I will use 15uS + 21uS = 36uS as the Base Period for now.

The driver I have can only run full step and half step, I am going to assume half step for now as I can not easily access the jumpers in order to verify.

Next I ran the stepconf wizard and set the IO pins for the parallel port and tried to fine tune and measure each axis.  I followed the directions in this PDF as well as this Tutorial.  There was some error with the Z travel distance and I had to run the program again after the initial configuration.  I was able to edit just the sections of the Z axis that I wished with out issue.  Really nice job on the Wizard/Druid thanks to EMC team.

In the end I decided on 2 revolutions per inch on the Z-Axis, had to open up the motor housing, measure with a caliper and then rotate the stepper shaft by hand.  Seems to be scaled right with what I can measure at this point.

I plotted a couple of the examples from the EMC examples directory just try everything and this is what the machine drew, using the pen tool on the Z-axis.


Leave a Reply