RCU Forums - View Single Post - Servo Programmer question
View Single Post
Old 07-13-2010, 07:33 PM
  #2  
mglavin
My Feedback: (31)
 
Join Date: Nov 2001
Location: Elverta, CA
Posts: 5,295
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Servo Programmer question

Daddy,

What’s your reasoning for centering the servo arm to be perpendicular to the case? In a perfect model where all things are equal this may make sense, but our model specific linkage geometry is anything but perfect. That said many believe it’s necessary to center the servo arm as you mention providing for equal surface deflection in either direction, unfortunately this is rarely realized. There are methods which can be used to realize equal surface throw with equal arm/control output; but almost always its a mechanical linkage thing verses the short cuts many use with programmable transmitter and servos.

That said, if you center the servo arm perpendicularly to the servo case and you want equal throw either side of center with regard to the servo arm only you’d program the travel arcs equal offsets in each direction, i.e., the servo centers at 1510us, you’d want to program equal numbers in each direction say 1510 + 300 in one direction and 1510 – 300 in the latter. Your actual numbers will vary dependent on how much servo arc or t ravel you want for the specific model.

Again all things are not perfect and the electro-mechanical variables of transmitters and servos may in reality skew these numbers a little, best way to insure you get what you want to is to use a simple photocopied protractor enlarged to suit your needs centered over the servo output shaft, follow the servo travel arc with respect degrees in both directions and program accordingly. Generally speaking servo travel arcs are 60 degrees either side of center (but you may require/want less or more).