Hitec 180 degree servo with Aurora 9x - RC Groups
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Aug 14, 2016, 04:06 PM
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Hitec 180 degree servo with Aurora 9x


I have an aurora 9 and for the slopes I have 180 degree mad stab elevator setup where the elevator moves 90 degrees in each direction to do flips and knife edge spins on slopes (good for nice flat spins too). Part of getting this to work is using roughly a 2/1 circular pulley ratio and I was wondering if I got the aurora 9x and a digital servo that I could program the servo like a HS-5070MH for 180 degree travel and use a 1/1 ratio and have much better resolution and smoothness than what I have now. Do I lose a lot of resolution when the servo is programmed for 180 degrees? Will the resolution of the transmitter make a difference for 180 degree travel?

Thanks!
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Aug 15, 2016, 10:31 AM
Xpress..'s Avatar
I believe you should be able to program the 5070 for 180* rotation, one way you can check is if you can spin the geartrain 180* by hand. You will need a Hitec programmer to do this.
Aug 15, 2016, 02:05 PM
Registered User
But one thing i saw in some videos is that you had to put the servo into a low resolution mode to program the servo for 180 degrees, which for my purpose is self defeating.

Setting a Hitec Digital Servo to 180° travel (2 min 8 sec)
Aug 15, 2016, 04:46 PM
Xpress..'s Avatar
Quote:
Originally Posted by mnavarro
But one thing i saw in some videos is that you had to put the servo into a low resolution mode to program the servo for 180 degrees, which for my purpose is self defeating.

http://youtu.be/uWLpEZJutZ4
This only applies to HS-7XXX series servos, 5XXX series are at a fixed resolution that you can't change.
Sep 25, 2016, 06:20 AM
Registered User
So does the HS-5070MH with the maxima RX/Aurora 9x support end to end 4096 resolution? I'm close to upgrading my Aurora 9 to a 9x. I found this at servo city:


Dimensions 0.92 x 0.45 x 1.14 (23.6 x 11.6 x 29mm)
Product Weight 0.44 oz (12.5g)
Output Shaft Style 25 tooth (B1) spline
Voltage Range 6.0V - 7.4V
No-Load Speed (6.0V) 0.14 sec/60
No-Load Speed (7.4V) 0.12 sec/60
Stall Torque (6.0V) 43.28 oz/in. (3.1 kg.cm)
Stall Torque (7.4V) 53.06 oz/in. (3.8 kg.cm)
Max PWM Signal Range (Standard) 750-2250μsec
Travel per s (out of box) .083/μsec
Travel per s (reprogrammed normal res) .116/μsec
Max Travel (out of box) 125
Max Travel (reprogrammed normal res) 174.5
Pulse Amplitude 3-5V
Operating Temperature -20C to +60C
Continuous Rotation Modifiable No
Direction w/ Increasing PWM Signal Clockwise
Deadband Width 2s
Motor Type Cored
Feedback Style 5KΩ Potentiometer
Output Shaft Support Top Ball Bearing
Gear Type Straight Cut Spur
Gear Material Metal
Wire Length 11.8 (30mm)
Wire Gauge 28AWG


Are these specs correct? If so it doesn't look like it's a high resolution servo at 174 degrees and you lose resolution at the larger range of motion.

I guess i am trying to understand whats the whole point of 4096 resolution if you cant use it... My use case is a good example of why you would like it. Maybe in the end its not significantly noticeable as I would be relatively happy with just the increase in servo range.
Last edited by funkyfreestyler; Sep 25, 2016 at 01:37 PM.
Sep 25, 2016, 04:19 PM
Registered User
Ok, so I did a little more research. Is the HS-7245MH (which has the 2.5 circuitry) the smallest servo that will do what I'm asking. Even if it's resolution is reduced to 2048 from 4096 when programmed to 180 degrees still would give twice the resolution of my Standard Aurora 9.

The max resolution of the HS-5070MH is 1500? If you do the basic math...125/ by travel per us .083 = about 1500 which is the same as 174/.116. But my Aurora 9 given it's 1024 resolution can't really access all of this. Just upgrading to the 9x with the same servo would give me 50% more resolution.. and going to the 7xxx models (which are 12 bit) will give me and additional 50% more resolution for 180 degrees. Am I understanding this correctly?
Sep 26, 2016, 12:24 PM
Xpress..'s Avatar
Here's the resolution rundown for our servos:

5XXX series: 1024
7XXX series: 2048
8XXX series: 4096
9XXX series: 4096
D-series: 4096

Out of the box, this is what the servos resolution is. Opening up the servos range of motion still gives you the same resolution, it's just the points won't be as fine.

The original G1 AFHSS operates at a max of 1024 resolution so that's all you're going to get out of any servo. Going to our G2 AFHSS (9X, Flash 7/8) gives you 4096 resolution as a max possibility, which only the 8XXX, 9XXX, and D-series servos can take full advantage of.

The speed itself can help improve how your system feels, depending on what airplane you use it in. Going from the old 1024 22ms equipment to the new 4096 7ms equipment in my 35% Yak 54 really improved how the airplane felt in the air- lot more crisp and precise than before.
Sep 27, 2016, 05:47 AM
Registered User
Ok, Last question on this and I promise we could put this to bed.

The HS-7245MH has the 2.5 circuitry (from the website) :

HS-M7990TH features our newest high resolution "G2.5" 12 bit generation programmable digital circuit .

Which means it 4096 resolution at some level, perhaps not end to end.
Sep 27, 2016, 11:38 AM
Xpress..'s Avatar
Not correct, all 7XXX series servos have a max of 2048 resolution.
Sep 27, 2016, 05:00 PM
Registered User
Well, 12 bit implies 4096, 11 bit is 2048, perhaps you're just not using the extra bit.
Sep 28, 2016, 11:41 AM
Xpress..'s Avatar
The G2.5 refers to a software version. The HS-M7990TH is a 4096 resolution servo because it has a magnetic encoder instead of a potentiometer, but the HS-7245MH is not 12 bit, it's just a standard 2048 servo.