Help Understanding Servos, Encoder and Motion Controllers
Hello Friends,
I am starting on my second machine. My first was a stepper motor machine. I am now wanting to servo a machine. I ran into some Galil products pretty cheap but I'm not sure if I can use them on these hobby type machines. I have a Galil DMC-730 motion controller, and 3 Galil 900ozin servos but I'm not really sure how it all works together. Sooooooo for starters any help with the following questions would be much appreciated.
Can the Galil DMC-730 work with a regular PC with Mach3 on it?
Can I use the 10 wire encoders with Gecko drives if I don't use the other Galil stuff?
And last, what other type of electronics would I need? I assume some type of power supply and maybe more???
Maybe I would be better off to off the motion control and buy geckos???? I looked on Galil's website and found no information about the products I have so I am guessing they are out dated. Thanks for all your help!!!
Allen
Encoder resolution for Gecko servo drives.
Quote:
Originally Posted by
freak_brain
Al,
Thank you very much!! A lot of this I don't understand but I am learning thanks to people like you.
I didn't look at that pdf until you posted a link... I just forgot to go back to their website.
Anyhow, Thanks again for your help. Now maybe the gecko people can help me on the resolution restriction of their products.
Allen
Hi freak brain.
I will answer what I can.
Geckos, from what I remember when I was setting up my control box, actually don't have an upper limit on the encoder count more or less. What is the limiting factor is the ability of the computer to generate the pulse stream fast enought to go anywhere at any type of speed. The standard is 500ct encoder in quadrature giving 2000 per rev. Your 1000 in quad, will be 4000/rev.
At a given pulse rate, you willl go 2 times slower. There are 2 ways around this. new encoders with 500 ct or the G340 servo drive with encoder multiplication which will allow you to get away with what you have.
The third option is to use a motion control card such as the smoothstepper or deskcnc card or other device that generates the step pulses and not the computer itself thru the pport.
Those 80v servos are a good match for the gecko's as the gecko has an 80 volt limit. I am assuming they don't have a ridiculus current rating. Max torque of a dc motor is direclty rated to its current draw. Limit the current and you are effectively limiying torque.
I looked at those renco encoders on ebay and will be buying some next week as they are a nice package and I several upcoming projects that will need encoders. Puls at $20 they are a bargain. If your motor has a 3/8 encoder shaft you can always turn the shaft down to 1/4 or I have read where people bore the encoder disc to a larger size. I have done this myself once and was very happy with the result.
Gecko accepts only single ended encoders, but you can use just the a and b pulses and ingnore the rest or get a differentil to single ended converter chip. Candcnc sellls these as part of his stuff or you can buy a chip from newarkinone or one of the other chip suppliers and do it yourself.
Al, some of the encoders have a ten wire connector comming out but they will only use 6-8 wires as needed.
Mike