Drive a digital rc servo motor
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Posts: 2
IS THERE ANYONE KNOW HOW TO WRITE A PROGRAM IN PROPELLER CHIPS TO DRIVE A·DIGITAL RC SERVO MOTOR?
Post Edited By Moderator (Chris Savage (Parallax)) : 11/9/2006 9:40:37 PM GMT
Post Edited By Moderator (Chris Savage (Parallax)) : 11/9/2006 9:40:37 PM GMT
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(Frequently heard from other's)
Tommy, I know it wasn't designed to·x, but can you make it·do x·anyway?
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Chris Savage
Parallax Tech Support
<http://ww1.parallax.com/Default.aspx?tabid=65>
There are other servos called "Super Servos" which require a 300hz update.· These require special hardware to drive them.· That is, a standard receiver won't drive it correctly.· They were meant to interface directly with solid state heading hold gyroscopes, which were specially designed to output a 300Hz signal, to complement the "Super Servo".· The higher rates give better servo response, which is really good for helping hold a model helicopter tail rotor.
Driving a servo is fairly straight forward.· Make a routine that outputs a positive pulse every 20ms.· Set the pulse duration to a width between 1.0ms and 2.0ms, which corresponds proportionally to the amount of travel.· 1.5ms is nominally the center point.·
Joel-
Silly me, I thought all digital servos used the 300hz update. Thanks!
Randy
One is the update from the receiver (or Stamp/SX/Propeller/Servo Controler) and this is usally 50Hz.·
The other update is from the servos internal controler board to the motor.· On many digital servos this is 300 Hz.
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John R.
8 + 8 = 10