EPA on a radio

[TC3 Benjammin]

Are end point adjustments on radios really that important?

[jeepinator]

YES !
They do two things:
1) Keep your servo from fighting a mechanical limitation (steering only goes so far)
2) Improves resolution throughout the useable range. This means that the finite amount of steps you are alloted will not be wasted on rotation that cannot be used.

[Nairb]

Very well said, Jeep. (He's right!)

[TC3 Benjammin]

That's great! Now explain to me in English. Thanks.

[jeepinator]

Each channel represents the full range of motion with a binary value. The binary value is 10 bits long. This equates to a range, in decimals values, from 1 to 1024.
So, in effect, 1 may represent a full rotation of the servo arm in one direction and 1024 represents a rotation of the servo arm the other direction. In other words, from a full left turn to a full right turn there are 1024 unique graduations, or steps.
If a servo has a total rotation of say 100 degrees (to make it easy), each step will rotate the servo arm about .1 degree.

If your servo hits a mechanical limitation at 50 degrees of rotation, you will only be able to use 512 of the steps. They will still be at the .1 degree resoltion.
If you set the EPA so that the servo will not rotate more than 50 degrees, then all 1024 steps can be utilized for this smaller rotation amount, giving you better resolution (.05 degrees per step).

God, that is hard to explain !

I hope you understand now, cause that is the best I can do ...

[jeepinator]

I did not spend 30 minutes figuring out how to eplain this for nothing.

... your welcome :rolleyes:

[draggerman11]

Thanks Jeep, that made perfect sense to me. Although it was not directed at me, thanks alot Jeep!

[TC3 Benjammin]

Jeepinator,

Thank you very much for the insightful post. You helped me immensely. Thanks for all the time you spent on me, I do not deserve your wisdom! Smartarse. :rolleyes:

[jeepinator]

Your welcome :p

Sorry for being a smartypants.
Did you REALLY understand it ?
It is a fairly important setting to understand (this goes for everyone, I suppose).

[draggerman11]

Yes Jeep, I did. You put it in English for us radio dumbies :p

[TC3 Benjammin]

I understand. Thanks.

[jeepinator]

You welcome.
Sorry for the misunderstanding. I was only looking for a bit of appreciation, especiallly since you wanted me to elaborate (at least that's what I concluded by the 'explain it in English' comment).

Enjoy your weekend !

[TC3 Benjammin]

No worries. ;)

[InspGadgt]

Very good explaination Jeep...Kudos...I do want to point out one slight modification to that explaination. The steps are inherrient in the transmitter not in the servo. That's why the old Futaba radio was called the 1024 because it was the only radio at the time in FM that had that finite of steps. The JR for example only had now i can't remember for sue but i think it was 756 hence the name of the radio...but it may have been 512. So by setting the EPA at the maximum physical limitation of the steering (or throttle in a nitro car) this as Jeep stated earlier allows you to use the full incremental steps of the radio through a reduced amount of servo movement.

[jeepinator]

It may not have come accross, but I do understand that.
There are no adjustments that can be made on the servo, so I was implying all adjustments (like EPA) are to be made on the radio.

It's all about resolution ;)