About digital servo

Joe

Hi,

I usually use the PULSOUT command to move
the Parallax standard servo and would like to know
if I could use the same rutine for a digital servo.


Thanks, Joe

W9GFO

Yes, the "digital" part of a digital servo refers to what happens inside the servo, not the signal used to control it.

All hobby servos use a digital signal for control and the PULSOUT command sends a digital pulse.

Rich H

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The Simple Servo Tester, a kit from Gadget Gangster.

Joe

Thanks ,


And two more questions about servos :

1-- Do you know if digital servos use
a potentiometer ?

2--There are some servos like the SAIL WINCH servos
that turns more than 360 º , even 15 times 360º like
a GWS servo ( S125 15T D ) .

But I don't understand how does this kind of servos ( multiturn)
stops , because the standard Parallax Servo has phisical (no electronics) stops at the end
of the travel.

Thanks , Joe

W9GFO

As far as I know, yes they all use potentiometers.

I have not taken apart a sail winch servo but I can tell you that multi-turn pots are not uncommon. I would assume that the sail winches use those and perhaps, the stops are the limits of the multi-turn pot. I don't know for sure.

I'm sure you could Google this and get more detailed information but the advantage of a digital servo is that instead of the servo's motor being energized 50 times a second (that how fast the pulses come in) like in an analog servo, the digital servo has a processor that receives the pulses at the same 50 times a second but energizes the motor at a much higher rate. The result is that the digital servo will hold or seek it's commanded position much better. The other advantage is some digital servos are programmable. I only purchase digital servos for use in my helicopters, it the only RC thing that I have that can really make use of the added precision and holding power. Other things like aircraft and cars do just fine with analog servos. Once side effect of the digital servo's precision is that many of them will buzz and some are quite noisy.

In summary, don't think that you need to get a digital servo. To realize the benefit of the increased precision a digital servo offers you will need to have linkages with zero slop - that means ball joints (or better) all around. If you are controlling the servo with a microcontroller then there is no need to have a programmable servo because you can do that in your software. Although if you are making something such as a walker that uses many servos then I could see the value in being able to program the servos.

Rich H

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
The Simple Servo Tester, a kit from Gadget Gangster.