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Old 04-30-2018, 01:48 PM   #1
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Default Analog vs digital steering servo question?

After going through two Traxxas oem 2075X servo units i installed this anolog 145 ouncer to get me by. It does quite well for trail and mild crawling. It is quiet and centers nicely with no chatter. I am thinking i'd like to try an analog 270 oz vs digital as i really like the non chatter and centering stability. I am using a Hobbywing 60bl esc . Is there any real advantage to digital?

https://www.ebay.com/itm/HobbyStar-A...72.m2749.l2649
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Old 04-30-2018, 02:13 PM   #2
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Default Re: Analog vs digital steering servo question?

Quote:
Originally Posted by willygee View Post
Is there any real advantage to digital?
Higher positional accuracy, better holding power, better centering, and much higher potential for torque and speed. Digital is pretty much better at everything a servo does or is supposed to do.

Last edited by svt923; 05-01-2018 at 06:54 AM.
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Old 04-30-2018, 02:43 PM   #3
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Default Re: Analog vs digital steering servo question?

I think the two 2075x (both failed first one super twitchey) left me with an attitude.I did notice the HW60bl esc provided smoother operation of my analog servo than the Traxxas XL 5hv
esc did..maybe because the bec has a higher rating.
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Old 04-30-2018, 04:08 PM   #4
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Default Re: Analog vs digital steering servo question?

Quote:
Originally Posted by willygee View Post
I think the two 2075x (both failed first one super twitchey) left me with an attitude.I
Traxxas electronics, go figure
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Old 04-30-2018, 04:40 PM   #5
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Default Re: Analog vs digital steering servo question?

The Stock Servo ist crap, way too weak for that heavy trex.
Without weighten the axlles a powerhd 20kg waterproof is a improvement. If you put weights on your axles it will come to it's limit. My next step was a Holmes sv500 i feed direct from my 3s lipo and this is a beast of a Servo. In a bend if it can't turn the wheel it turns the hole truck

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Old 05-01-2018, 12:51 AM   #6
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Default Re: Analog vs digital steering servo question?

The digital servo's just out perform old analogue. The other issue you face is that reputable servos will be digital so if you find analogue ones then the quality control maybe questionable. The old adage 'Buy cheap, buy twice' is so suited to servos! :-)
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Old 05-01-2018, 12:33 PM   #7
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Default Re: Analog vs digital steering servo question?

It's an RC Helo site, but the logic applies to other areas of the hobby as well.
https://www.rchelicopterfun.com/rc-servos.html



"...digital servos have much improved deadband, better resolution, faster response, quicker and smoother acceleration/deceleration, and immensely better holding power.

You can test this very easily by plugging in a digital servo and an analog servo to your receiver. Try to turn the servo wheel off center on the analog RC servo.

Notice how you will be able to move it slightly before the servo starts to respond and resist the force - it feels a bit "spongy".

Now do the same thing with the digital RC servo. It feels like the servo wheel and shaft are glued to the case – it responds that fast and holds that well."



However, do note that digital servos require more input power relative to output power, when compared to Analog:


"Yup, digital servos are power hungry. All those hundreds (thousands) of power pulses per second use up more battery power than an analog servo would. This really is not that much of a problem these days since RX battery packs have at least double or triple the capacity of what the same size/weight pack had just a few years ago. That said, it can be a big issue for your BEC (internal or external) or a voltage regulator all of which have a finite maximum current output. "


Since RC cars/trucks generally only need one servo doing the hard work (steering servo), digital makes sense as it's still usually well within a BECs output to power them, until you start getting into high end models, or want to up the voltage to increase torque output

Conversely, for my RC planes I used to to strike a balance: I use analog for more basic functions (eg. flaps and landing gear), where generally the servo is simply traveling from point A to B, and precision or response time isn't that critical, but efficient power output, and lower cost, are. For my main controls (especially the all-important elevator), digital is the way to go.

More recently though, as digital servos take over the hobby, it sometimes makes more sense to just go digital all around, and beef up the BEC if needed.

Last edited by AggressorBLUE; 05-01-2018 at 12:40 PM.
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Old 05-01-2018, 05:44 PM   #8
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Default Re: Analog vs digital steering servo question?

the RC helicopter fun link was very informative thank you.
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Old 05-02-2018, 09:59 AM   #9
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Default Re: Analog vs digital steering servo question?

no problem!
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