DC Servo control

[Quicksilver1]

Hello,
I'm attempting to vary the speed on modified for 360 degree op DC servos with the MC9s12DP256DGV2 PWM. The servo is the HS645.
I've found the correct frequency and duty cycle on a signal generator, and am having trouble when I connect the PWM to the servos I've verified my calculations more than once and have verified my outputs with an O-scope.
I recently searched the forums here and found that a I can control these servos with a MOSFET.
So my questions are:
1) Is this a correct assumption?
2) If so, how do I go about choosing the correct one? and
3) How do I do it?
Any help would be appreciated.
Thanks in Advance,
Hector

 

[Skogsgurra]

Sorry that I am not at all aware of the equipment you are mentioning. The only HS645 I can find is a servo that is gearad towards model builder's RC and the MC9s12DP256DGV2 didn't pop up at all. Not until I had reduced the letters down to 12DP256, which sounded somewhat familiar (a micro controller).

Does this mean that you are trying to drive a servo motor directly from a micro controller's output pins?

If so, you need more help than just a short advice. Hint: study the characteristics of the motor (amps and volts needed) and then compare to what the micro's output pins can deliver.

So, yes, you can use MOSFETs to increase drive capability. But you will have to find the corresponding applications notes yourself. We do not do design work here. Also, there are certain restrictions regarding hobby activities. Please read about site Posting Policies by clicking text below the Submit Post button.





Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[Quicksilver1]

Skogsgurra,
Thank you, and I do apologize as I believe that my post has violated some of the posting policies. I did not see those in the beginning of the post. I do not see a spot to delete the post, so I can not do it myself. So my sincerest apologizes go to fellow board members.
Thank you,
Hector

 

[Skogsgurra]

No probs. I think that your post will survive - at least you do use proper language and punctuation. Not many hobbyists do that.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...