Originally Posted by
Darkgenerals
My point is Tekin used that method because of the 360 degree rotation, its not superior technology for something like a servo.
Check out this link where people way smarter than me discuss encoder vs potentiometer. To sum it up however, something like a savox 1256TG has better resolution per degree of movement than Tekin's encoder. You can even do the math, 4096 of resolution over 200 degrees of movement. Thats .0488 degree per 1 value on the potentiometer.
My point is they did not use it just for 360. It IS a superior technology that we will notice on the track.
I work with magnetic encoders and potentiometers weekly. I took multiple classes on feedback/control loops in school less than 2 years ago, and I program 3d printers in my spare time that use position sensors. They both have benefits and drawbacks, of which most aren't mentioned in that short thread. For RC, the magnetic encoder provides more accuracy. Resolution does not equal accuracy. I'll try to detail this below.
Even in that thread, someone posts this:
"Potentiometers are often less costly than encoders, but they can be more affected by the environment (vibration, water, etc)."
Potentiometers rely on physical contacts sweeping across wires to change the resistance (thus the voltage). The processor measures the voltage and uses that to determine position. Since the resistance properties of all matter changes with temperature, the measured position will change as well.
Lets do an example:
0 volts equals center. +6 volts is full left and equals 90 degrees. We will ignore left, but for reference purposes it is -6 volts and -90 degrees.
Lets say this happens at a temperature of 60 degrees.
If you told the servo to go to 45 degrees, it would turn the gears until it saw 3 volts coming back from the potentiometer. If it saw 3.1 volts, it knows it went too far. Now, you've ran your car for 20 minutes and the servo has warmed up to 70 degrees. Heat increases resistance, so in order to get a measurement of 3 volts (where the potentiometer "thinks" it is at 45 degrees) it actually has to travel to 47 degrees. Having many steps of resolution means the servo can be precise. However, you can be precise and not accurate.
Also, as the servo ages the potentiometer will continue to wear out since there is a physical contact that moves inside it. It's like a brushed motor and this will further affect the voltage measurement, causing a larger error in the accuracy of the servo. It still would have the same resolution, but the accuracy is what truly matters.
Magnetic encoders are contactless, just like brushless motors. They are no less accurate 10 years after using them than they were when new. If you buy servos and sell them 2 years later, you might not notice a difference due to wear between a potentiometer and an encoder (you will still have variations based on temperature and other factors). If you keep servos for a long time, you won't have any degradation in accuracy after using them for multiple years.
so lets sum that up.
its programmable (agreed)
aluminum case (agreed)
better gears (which I'm waiting for you to prove)
Never claimed it was better. I listed it as something that affects price.
response time ( Again lets see some proof to this one)
Never claimed this. I listed it as something that affects price and isn't reflected in the speed spec.
Better position sensors ( not true)
See above why they are better.
I was just interested in what that means for this servo. ESC has a few more functions than a servo, can any of the servo's do data logging?
There are servos that do data logging. I have no way to know if this is a feature at the moment for the Tekin servos. Here are some wild things I made up that could potentially be added later:
A limited/adjustable torque option. Say you have a steering rack that you are worried about breaking. You can set the maximum torque the servo will apply so that on crashes and hard impacts, the servo gives a bit to save the steering system. Or this could be used for nitro cars on the brakes to make them more linear feeling.
Adjustable stall parameters. Say the servo is unable to move to the position you are inputting on your radio because it is wedged under a pipe. If the servo can't reach the desired position after an adjustable amount of time, it could cut power to the motor to prevent damage.
Failsafe positions. Rather than relying on the receiver to demand a failsafe setting, the servo could have a backup default position to prevent nitro runaways.
A low power mode. Say the input voltage drops suddenly. You could program the servo to reduce power draw to avoid a receiver brownout.