[runiko]

Hi, I'm just starting off my journey through DIY CNC milling, and I was hoping for some help, since Google has failed me .

I have a bunch of servo motors that I am modifying to use a 15-turn potentiometer. I am not having trouble with that. it is hooked up to a little test circuit with a 556 timer and big control potentiometer on it. That works great.

The problem is that I want to now hook the servo up to my computer's serial port and have Mach3 turn it. It doesn't have to be perfect right now, I just want a proof of concept. Stepper motors can be controlled via the serial port with just some simple components wired up without any microcontrollers or anything like that. How can I do the same for a servo motor? I don't want to have to buy and program an arduino or pololu or whatever, I just want it to connect to the port and take commands directly with mach3 running it.

What do you think?

Thanks in advance!

[Iron-Man]

Mach III uses the parallel port.
For DIY Servo check out this link.
http://www.cnczone.com/forums/showthread.php?t=40940

[mcphill]

What are you calling a "servo" motor - an RC model servo, or an industrial servo with a built in encoder?

Post a make and model number, and better yet a link to the part datasheet and you may get some useful replies.

[runiko]

Thank you for your replies, my newbie-ness is showing through, eh? sorry

I have three JR Sports ST126MG servos which I am really having fun with even on my simple little test circuit. They don't have any built-in anything besides the pot comparator circuit.

Looking at Mach3, it seems that it could just hook up through the parallel port (I said serial port up above, didn't I? Oops) and have it generate the 1-1.5 ms patterns to direct the motors by hooking their "signal" wire up to the corresponding pin of the port, and have it be fast enough to divide the 15 turns of the servo into small enough steps. Am I incorrect in this? I'm trying to track down something about it on Google, but the guiding hand of an experienced mach3/servo user is probably going to be so much more helpful.

[japroach]

If you wanted to control an RC servo directly via mach3, you'd probably have to write a plugin. The only similar feature I can think of is PWM spindle control.

Or you could use intermediate hardware (cpld or microcontroller), that would receive a step direction command from mach and convert that to a servo pulse.

[S.Almajid]

Hi is any can help me i have problem in my Quick CNC china machine i am new in these field i have a problem my DSP 0501 control system is not working nothing display in the screen .can anybody help me what i have to do i am in trouble.pleas send the solution throw my e mail.
[email protected]
Thanks
Alnajar

[Iron-Man]

See the following links;
http://openservo.com/
Open servo has a digital servo project based on the AVR MCU. You should be able to modify the software to work with mach 3. Also check out this site,
http://www.servomagazine.com/
I hope this helps.

Iron-Man