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Mach Discussion => General Mach Discussion => Topic started by: dgalaxy on February 19, 2007, 10:40:39 AM

Title: 2000 line encoder mach3
Post by: dgalaxy on February 19, 2007, 10:40:39 AM

Hi i have almost buttoned up my stepper plasma table now im working on my mill  i have the rutex servo drives and 29" nema42 servo motors i have a question i was told that you cant run 2000 line encoders with mach3 is this true i was told that it would run real slow i need to get 500 cpr  . the reason im asking this is because i allready have the 2000 line encoders they came with my motors just wanted to make sure before i purchase some new encoders
Thanks JOhn

Title: Re: 2000 line encoder mach3
Post by: Chaoticone on February 19, 2007, 11:26:48 AM

Hey John,
    What kind of speeds are you looking for? I think the problem with the encoders you have now will be Machs max pulse rate of 45Khz. 45,000 pulses per second.

Brett

Title: Re: 2000 line encoder mach3
Post by: dgalaxy on February 19, 2007, 12:30:19 PM

I have seen the video where mach was running a mill at 60ipm but i think that is going to be way to fast for my level i was thinking maybe around 20ipm or less at the very most ill be cutting mainly 1018 steel some aluminum with various cutters  iwas going to try the us digital 500 cpr what do you think  it is just a 9x42 bridgeport with hiwin ballscrews i installed nothing fancy

Title: Re: 2000 line encoder mach3
Post by: Hood on February 19, 2007, 01:27:39 PM

You will want 100IPM plus on a Bridgeport ;)
 What are the pitch of the ballscrews? Do you have any reduction between them and the motors?
Hood

Title: Re: 2000 line encoder mach3
Post by: dgalaxy on February 19, 2007, 02:57:13 PM

P.C. Dia. 1.28"
Ball Dia. 0.125"
Lead Angle 2.84°
Circuits 2.5 x2
Lead 5TPI
Static Load 12491 lbf
Dynamic Load (1x106 revs) 4158 lbf
Lead Accuracy 0.0003"/2&Mac185;;0.0005"/ft
Drag Torque (Preload) 3.5 in-lb(280lbs
im going to run probably a 2 to1 5mm pulley i have a friend that works at j&K pulley here in st.louis hes making me some pulleys for my machine

Title: Re: 2000 line encoder mach3
Post by: Chaoticone on February 19, 2007, 03:10:19 PM

Hey John,
    Hood is right, he's bad about that. You will want at least 100 IPM. If you are running a screw that is 5 TPI, it has a .200" lead. It will have to turn 5 rounds to travel 1 inch. With 2-1 pullies that makes it 10 revs of the motor to move 1 inch. I think a 2000 line encoder (let someone confirm this) will take 8000 pulses to turn 1 round. Your max speed with this set up would be 45,000/80,000=.5625 rounds per second X 60 = 33.75 Inches per minute. It will run like this but unless you are very patient, you will not be happy.


Brett

Title: Re: 2000 line encoder mach3
Post by: dgalaxy on February 19, 2007, 03:25:58 PM

OK i geuss i need to get the 500 line encoders for sure

Title: Re: 2000 line encoder mach3
Post by: Hood on February 19, 2007, 03:41:38 PM

Yep, for a 500 line encoder it would be 45,000/20,000 x 60 = 135IPM
What is the max RPM of your motors and at what Voltage?
Hood

Title: Re: 2000 line encoder mach3
Post by: HillBilly on February 20, 2007, 07:17:37 AM

I think the step multiplier in the Rutex drives will allow you to use the higher count encoders for the servo loop.

I may be wrong but it looks like you can set one step pulse to equal ********* amount of encoder pulses.

Darek

Title: Re: 2000 line encoder mach3
Post by: guynamedbathgate on February 20, 2007, 07:51:13 AM

just thought Id write in and say Im using 1000 line encoders for my servo system on Mach. Works great. dont know about 2000 though

Title: Re: 2000 line encoder mach3
Post by: dgalaxy on April 11, 2007, 05:11:43 PM

Well i got my encoders mounted 500 usdigital and im still playing with it im just fascinated by servo i have sem 29 inch nema 42 and these suckers i think are big compared to my 260 steppers. and  mach3 will make these things  switch direction so fast they will jump off the ground usually when i show my wife stuff she could care less  but she even thought that the servos were impressive  just making my own conclusion about the stepper vs servo war   from a green horn rookie point of view

John\

another thing hey guys right now im running 70v at 1500kva   do you think i should be running this P.S in series 140 v at 750kva my motors can handle 180v 8.8 amps 3 of them

Title: Re: 2000 line encoder mach3
Post by: guynamedbathgate on April 12, 2007, 05:57:13 AM

I hear yah.
Im using servo's on my mill and they run so freakin nice. cant say the same for the stepper on my rotary table.
Chris ::) ::)

Title: Re: 2000 line encoder mach3
Post by: polaraligned on April 12, 2007, 02:02:29 PM

I'm running 1000 line encoders on my servos which are geared down
4:1 driving a 5TPI ballscrew.  I am using gecko drives with the step
multiplier set at x5.  I should be able to run 168 IPM with this setup
but my Gecko's fall apart at anything over 120 IPM.  They just can't
handle the fast count rate that the encoders put out. 

Scott

Title: Re: 2000 line encoder mach3
Post by: Brian Barker on April 12, 2007, 02:31:05 PM

That is a bit much for a G320 :(

Title: Re: 2000 line encoder mach3
Post by: dgalaxy on September 28, 2008, 07:50:22 AM

Sorry i have been neglecting my mill for some time finally got my plasma table up to par.

Im useing rutex 2020 drives 29 inch motors  at 67 volt 15kva us 500 line encoders and a 5tpi at 2to 1  max motor rpm is 1550 at 120 volt
i have my velocity set at 30 and my accelration set at 5  and it seems im loseing steps  it is alot better in exact stop than cv   does 30 and 5 seem like a good starting place
once i hit cv it is real bad any suggestions

John