# Machsupport Forum

## Mach Discussion => General Mach Discussion => Topic started by: McYoda on September 08, 2008, 03:17:18 AM

Title: Calculating Step For Mach
Post by: McYoda on September 08, 2008, 03:17:18 AM
I like how to calculate the step for Mach when using step motors. I plan to build another new machine using servo motor and gear rack.

The equipment would be like this.

Servo Motor RPM = 3200
Gear Rack = 20 DP
Pinion = 20 Teeth
GeckDrive = 320
Decoder = 500 CPR
Gearbox/belt = 9

I think that is everything I need. How do I get the steps for Mach?
Title: Re: Calculating Step For Mach
Post by: Hood on September 08, 2008, 04:21:59 AM
What are you meaning by the Gearbox/belt = 9? is that a reduction of 9?
Without any gearing then 1 rev of motor moves 1 inch, one rev of motor is 2000 pulses (500 x 4) so that is what your steps per unit will be.
If you have a 9:1 gearing then it will need 9 revs to move 1 inch so Steps per would be 2000 x 9 = 18,000.
Hood
Title: Re: Calculating Step For Mach
Post by: McYoda on September 08, 2008, 10:49:07 AM
Thank you for the clear explanation.

What are you meaning by the Gearbox/belt = 9? is that a reduction of 9?
Without any gearing then 1 rev of motor moves 1 inch, one rev of motor is 2000 pulses (500 x 4) so that is what your steps per unit will be.
If you have a 9:1 gearing then it will need 9 revs to move 1 inch so Steps per would be 2000 x 9 = 18,000.
Hood
Title: Re: Calculating Step For Mach
Post by: writerson on April 07, 2010, 05:49:44 PM
in this calculation, how many step per do we need to turn this servo 3200 RPM ?
Title: Re: Calculating Step For Mach
Post by: Hood on April 07, 2010, 06:06:00 PM
Depends what  line count your encoder is.
Hood
Title: Re: Calculating Step For Mach
Post by: writerson on April 08, 2010, 02:53:34 AM
if we have 2000 line encoder,, how many step per do we need to turn this same servo motor 3200 RPM
Title: Re: Calculating Step For Mach
Post by: Hood on April 08, 2010, 03:28:01 AM
If its a 2000 line encoder then that is 8,000 in quadrature so 8,000 x 3,200 = 25,600,000 pulses per min/60 = 426,666 pulses per second (426KHz)
If it was a 500 line encoder then it would be 2,000 x 3,200 / 60 = 106,666Hz (106KHz)

Hood
Title: Re: Calculating Step For Mach
Post by: writerson on April 08, 2010, 06:51:16 AM
i understood that i'll need 426Khz for 2000 line - 8000 in quadrature for 3200 RPM ! but what will be the "step per" in this calculation ?  ( 8000 ? )
Title: Re: Calculating Step For Mach
Post by: Hood on April 08, 2010, 07:14:29 AM
It all depends on what the pitch of the ballscrews are and if you have any reduction between the motor and the ballscrews.
Hood
Title: Re: Calculating Step For Mach
Post by: writerson on April 08, 2010, 07:43:10 AM
i didnt mean any movement of axis.. i just mean, how many  "step per" do we need to turn motor 3200 RPM with 2000 line encoder.. we need totally 426,666 KHZ but.. what could we set "step per" from motor tuning to turn servo 3200 RPM ??
Title: Re: Calculating Step For Mach
Post by: Hood on April 08, 2010, 07:44:52 AM
If you are calling one rev of the motor as 1 unit then 426,666/3,200 will be the steps per unit.
Hood

Edit sorry thats wrong, if 2000 line encoder thats 8000 per rev so if one rev is one unit then its 8000
Title: Re: Calculating Step For Mach
Post by: writerson on April 08, 2010, 07:49:28 AM
again a little confused !!! cant we turn this servo continuous 3200 Rotation Per Minute ?? or 533.333 Rotation Per Second ?
Title: Re: Calculating Step For Mach
Post by: writerson on April 08, 2010, 07:54:03 AM
if i set 8000 to "step per" it means that it will turn 3200 RPM right ? (for this calculation)
Title: Re: Calculating Step For Mach
Post by: Hood on April 08, 2010, 08:00:19 AM
If you set the steps per at 8000 that means when you command a move of 1 unit per minute the motor will turn one revolution in one minute and the pulses sent out will be 8,000 per minute.
If you command a speed of 3,200 units per minute then that will be 8,000 x 3,200 = 25,600,000 pulses sent out per minute or 426,666 pulses per second.

Hood
Title: Re: Calculating Step For Mach
Post by: kf2qd on April 12, 2010, 03:58:52 PM
Is this a spindle motor?