Controlling servos?

[crash80]

Hi all,
I am very new to building any type of cnc system. My profession is machining requiring programming, running, fixing our various machines. Typical maintenance machinist. But, enjoy other hobbies like flying RC Helicopters, racing Go-Karts etc. and I always modify or build new stuff for all my stuff. I am lucky that my employer allows me to use the equipment after hours to build my stuff.

Now I would like to build a small cnc machine for my garage. I am looking at an X-3 or X4 type machine. Now, I would like to possibly build my own control boards but I have a problem. I don’t know much about electronic circuitry. I understand electricity, pretty simple, but when circuitry is built then I get lost.

What I ask from any of you is if you would help point me in the right direction for understanding servos, steppers, control boards, etc. . I am looking for books, software, anything that will help me understand the system. I know I can just buy the stuff, which is fine, but I also want to learn what is happening, why it’s happening, and how to diagnose a problem if one was to occur.

I currently have a small servo that I would like to use to experiment with to see if I can make it work. But, I know nothing about it. This is what is on it.
Emerson
3 phase brushless
240 VAC
3.0 A.
0.47 HP
0.35 KW
5000 RPM

Now I know the volts, amps, H.p.,etc. stuff, but the thing has a single connector that has 18 pins in it. Why, that’s what throws me off. I see 3 poles for the motor, but why 15 for the encoder? Then, how to I figure out which pin is for what? How do I check to see if it’s good or bad? This is the kind of info I am looking for also.

Thanks,
T.J.

[Al_The_Man]

The first thing you will need is the spec sheet on the motor you have, this will give you the requirement for commutation and the feedback encoder type/pin out.
If you are starting from scratch, let google be your friend and learn as much about the basics first, there is a wealth of information out there, starting with the commutation of your motor.
http://users.tinyworld.co.uk/flecc/4...otor031102.swf
Al.

[mcphill]

You likely need a servo controller that will power that motor and interface with the encoder to give it the proper closed-loop control. Some are more "universal", and some are relatively "proprietary". Stepper motors are quite universal, but servo's much less so.

[Al_The_Man]

You will also need to know the difference between a PID loop that is controlled/closed back to the drive and one that the loop is closed back to the CNC controller.
Al.