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Author Topic: Motor tuning for Series 1  (Read 829 times)

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Motor tuning for Series 1
« on: May 13, 2017, 03:52:50 PM »
I am setting up Mach4 for a Bridgeport Series 1 Boss4 with its original Sigma stepper motors with the cooling fins. In the motor tuning section of Mach4 there is a simple math equation for calculating "counts per inch" which requires specs for the stepper motors and I don’t have a clue.

1. Does anyone know the following specs for the Sigma motors?
- steps per revolution
- screw pitch ratio

2. Are the specs the same for all three motors X, Y, Z?

3. I am using a PMDX-424 controller board which has “step pulse signals up to 100 KHz”. How does this relate to the motor tuning, or does it?

Re: Motor tuning for Series 1
« Reply #1 on: May 13, 2017, 05:25:14 PM »
The motors are standard 200 full steps per revolution.

I think the screws are 5 turns per inch.

On a Boss 4 machine if I recall correctly, the ratio from the motors to the screws is 1:1 but
some later machines were 2:1 ratio.

Your motor drivers will likely be set for microstepping which increases the number of steps
required by the microstepping factor. We would likely recommend 8 for this machine.

All three motors are the same.

The 100 KHz will determine the maximum speed possible but does not affect the counts
per unit of motion calculation.  Remember that is thousands of cycle per SECOND and motion is
measured in inches per MINUTE.

For the assumption of 8 micro steps, 200 step motors, 5 TPI screw and 1:1 ratio, you would
need 8000 steps per inch of travel. Given 100,000 times 60 second per minute, the PMDX-424
can produce 6,000,000 steps per minute, resulting in a limit of 750 inches per minute. That
far exceeds the 100 inches per minute that this machine is typically capable of running.
Steve Stallings
For PMDX product support, please use PMDX forum or direct email for quickest response. We do not use this forum as our primary product support site.
Re: Motor tuning for Series 1
« Reply #2 on: May 15, 2017, 03:31:17 PM »
Those settings did the trick. Great PMDX support, per the usual. You answered my questions before, during and after my PMDX purchase. Thanks Steve!