Talk:Servo control

duration vs PWM

"When a pulse is sent to a servo that is less than 1.5 ms the servo rotates to a position and holds its output shaft some number of degrees counterclockwise from the neutral point. When the pulse is wider than 1.5 ms the opposite occurs."
This article seems to be written for a specific servo.

"that position is always around 1.5 milliseconds (ms)"
Milliseconds are not a unit of position, even if they are linearly related in this context.

"...not defined by the PWM duty cycle (i.e., ON vs OFF time) but only by the duration of the pulse"
They are the same thing.

— Preceding unsigned comment added by 198.95.226.40 (talk) 20:27, 19 March 2012 (UTC)[reply]

Yes, I used to think that RC servos were controlled by PWM duty cycle, just like all other DC motors.

I've added a paragraph attempting to explain "RC PWM" and how it differs from other kinds of PWM.

The PWM duty cycle (ratio of ON time relative to the pulse repetition rate) is not the same thing as the duration of the ON time.

For example, I can set the duty cycle knob on my function generator to "10%" and then turn some other knob that changes the ON time while maintaining a constant 10% duty cycle. RC servos are entirely controlled by the ON time, more-or-less ignoring PWM duty cycle. Other DC motors are entirely controlled by PWM duty cycle, more-or-less ignoring the ON time.

How can we make this article explain things more clearly to new readers? --DavidCary (talk) 17:54, 23 October 2012 (UTC)[reply]

merge

I have proposed merging Servo bandwidth with this article. Biscuittin (talk) 21:23, 31 October 2011 (UTC)[reply]

I think there is a case for merging Servo bandwidth, Servo control and Servo pwm. After these three have been merged, perhaps we could re-examine the case for a merger with Servomechanism. Biscuittin (talk) 22:28, 31 October 2011 (UTC)[reply]

If there are no objections, I propose to merge Servo bandwidth, Servo control and Servo pwm on 16 November 2011. Biscuittin (talk) 09:00, 2 November 2011 (UTC)[reply]

I don't object. I'd like to see more on the article about how the servos rotate, though. Oh, I see now that the information I'm looking for is on the servo mechanism page. Perhaps a merger would be useful, but I'm not knowledgeable enough about the subject to make that kind of judgement personally. But you have no objections from me. BriEnBest (talk) 08:36, 13 January 2012 (UTC)[reply]

I'd oppose merging servo bandwidth because it's about the broad topic of servomechanisms (and some heavy maths), not simple radio control servos.

Servo pwm was deleted because there just wasn't anything in there worth keeping.

Servo (radio control) was created as an obviously important topic that had somehow been missed. There are notes on its talk page for what else is needed in that article. It's very small at present, so I'm against merging servo control into it. Servo control is a useful article for those who care about the timing diagrams and is worth keeping in its entirety (or even expanding). If it were merged into the servo (radio control) article at present, it would make it unbalanced. Escapement (radio control) could even be split out of servo (radio control) at some time, as that's interesting, but only in a historical sense. Andy Dingley (talk) 16:44, 13 January 2012 (UTC)[reply]

RC versus wired

for past five years this page has assumed that servo control with pwm is about radio control; but not all servos having pwm control are radio operated. hobby servos using a pwm interface may be wired, as well. [1] -- 135.23.66.249 (talk) 17:40, 18 September 2016 (UTC)[reply]