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Author Topic: mach 3 and encoder  (Read 4820 times)

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Offline ziga

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mach 3 and encoder
« on: September 10, 2007, 10:13:09 AM »
Hi

I hope i posted the question in the wright addres

I have a cnc mill wich i wuld like to 'rebuild' from steper to servo motors, i am thinking of buying a gecko drive for brush dc motors. and now i am searching for encoders. I found these RM22and RE36, they are both nice, but i am having some questions, how do i wire tham up? they do not have only a and b signals, they have z, z-, a-, b-? what about these? and how does mach and gecko drive think about counts per revolution? it changes at 2500 it is 8129 counts, and at 5000 it is only 4096, and what about speed? when i am having a stepper motor i use only 200 step pulses to make a turn when i will be having encoder i will need 8129 or 4096 or is it something between??

Could somone plese help me understand these?

Ziga
« Last Edit: September 10, 2007, 03:07:30 PM by ziga »
Re: mach 3 and encoder
« Reply #1 on: September 11, 2007, 10:29:11 PM »
Rogers machine has a nice board for the encoders to hook into and most of the users only use about 250 - 500 count encoders.... a 500 line will give you 2000 PPR of the servo and that is as good as you are going to get from a stepper... Also have a look at US Digital for the encoders.

Hope that helps
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline ziga

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Re: mach 3 and encoder
« Reply #2 on: September 12, 2007, 04:37:47 AM »
yes i have a machin with stepper mottors but, at these moment, but i am thinking of buying a bigger machine and fitting it with servo motors dc brush, so i am gonna have to put in encoders, and i would like to have aroun 0,001mm accuracy.

So even at full speed, my spindle is 5mm per revolution, that would make it, 0,00123mm accurately. at 4000 rpm with RE36.

But these encoder have A, B, Z, and -A, -B, -Z wires wich ones do i have to hook up on my computer for a and b inputs?

and i have another question(related to gecko drive G320 and encoders)
encoders must be hoked up on it the same way as in my paralel port. so whan a machine gives a 5 steps order gecko drive will move for 5 steps, and than it will barake the mottor, like the stepper motor, or it will slowly stop, havenig some moment and keep going?
(i didnt get the answer at gecko drive)
Re: mach 3 and encoder
« Reply #3 on: September 12, 2007, 10:50:50 AM »
Use A and B for the computer and the drive...

The srtating and stopping of the servo motor is all done in the drive.. This is a PID loop (of sorts) and it is trying to correct the error all the time. So if it is out of position it will fight to get back.

Hope that helps
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline Whacko

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Re: mach 3 and encoder
« Reply #4 on: September 12, 2007, 02:38:24 PM »
Just a note, there is a company that boasts that they are the 10 Dollar encoder company. I have used them, they work very well. Best check it out at http://www.usdigital.com
If you are not in the states, you can order from just about anywhere in the world.

Whacko
Nothing's impossible

Offline ziga

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Re: mach 3 and encoder
« Reply #5 on: September 12, 2007, 05:06:13 PM »
yeah i think this is just what i need.

I found some encoders which cost around 60 - 157 euros depends on resolution, but you need to wire it up to some chip, wich transforms a signal in-to end signal, couse the actual output of the encoder is 2 week. but thay are very expencive, but have resolution up to 8129 resolutions per rev