Rc Servo Controlling question...

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hamedhbbb
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Rc Servo Controlling question...

Post by hamedhbbb » Wed Jun 21, 2006 2:28 am

hi guys...

i need some info please

i wanna know if i send pulses to a servo and i put a 5 or 10 mseconds between pulses (not 20 ms) what happen? is it dangerouse?
it means that signal ferequency is 100Hz or 200Hz...

if yes then why? and how much? !

when i test this.servo works normally.


thanks
hamed

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Sambuchi
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Post by Sambuchi » Wed Jun 21, 2006 10:01 am

20ms "time period" is a spec for every servo motor.

A servo should tell you the min "time period" required to use the motor.

Each servo has a built-in controller that responds to electrical pulses sent to it.

Servos will not respond to just any pulse width; rather, they are limited to a defined range of pulse widths. Most servos have a minimum pulse width limit around 1.0ms and a maximum limit around 2.0ms.

I think that is the standard for Futaba servos..

Sending a pulse whose pulse width is outside this range may damage the servo’s control board. Repeatedly sending these bad pulses will almost certainly destroy the servo.

Servo manufacturers suggest placing a small delay of at least 0.02s (20ms) between pulses to prevent overdriving the servo... also bad and could damage the servo.

dyarker
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Post by dyarker » Wed Jun 21, 2006 1:02 pm

I think he's using the right pulse widths, it's the period he's playing with.

If it works, it's alright within reason. The 20mS period standard allows control of multiple servos over an RF link.
Dale Y

hamedhbbb
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Post by hamedhbbb » Thu Jun 22, 2006 2:17 am

hi

yes, i dont change pulse withs, its 0.7 to 2.7 ms for my servos.
but my question is about period... which for most servos is about 20 ms.

i wanna change it to 5 or 10 ms. i did it before for test, ... and servos works normally with that period ,but faster and stronger. it doesnt warm up!

so, whats your opinion? can i use 5 or 10 ms period with this servos or not?
i dont wanna use RF, i control servos with MCU

thanks

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Sambuchi
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Post by Sambuchi » Thu Jun 22, 2006 4:03 am

... well if you read my first post, changing the 20ms may cause overdriving.. dont do it

Sambuchi wrote:20ms "time period" is a spec for every servo motor.

A servo should tell you the min "time period" required to use the motor.

Servo manufacturers suggest placing a small delay of at least 0.02s (20ms) between pulses to prevent overdriving the servo... also bad and could damage the servo.

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