Subtrim

[rguptaca]

I have read the old FrSky OpenTx manual with regards to subtrims.
Both modes use an ofset.
Is there a reason we don't have a one click option to move the servo center point?
1500us moved to 1550us keeping the +-512us.

[Kilrah]

It's waiting for you right there in the "PPM center" column.

[rguptaca]

Is there a reason we don't have a one click option to move the servo center point?
Trims => Subtrims is one long click.
I don't see Trims => PPM centre.
Was wondering if there was a reason for this?

"The last line after CH32 is the "Trims to Offsets" function. It is used to take the trims of the currently selected flight mode, transfer their content to the subtrims, reset them, and adjust all other flight modes' trims. If you're close to running out of trim, instead of having to adjust every value one after the other, all it takes is to LONG press ENTER on this line and everything is done magically."
- from http://www.open-tx.org/2013/08/22/opent ... manual-en/

Would it not bee the same for PPM centre, save adjusting one value after another?

Trying to understand the history of development and learn.

Also is 1500us the position of pulse position or is the centre of pulse width. I believe it is PWM centre position along with the high and low limits in terms of pulse width based on my reading below.

http://www.societyofrobots.com/images/a ... ontrol.jpg
From http://www.societyofrobots.com/actuators_servos.shtml

http://ebldc.com/wp-content/uploads/200 ... rc_pwm.jpg
From http://ebldc.com/?p=48

[Kilrah]

Is there a reason we don't have a one click option to move the servo center point?

Yes, because having this adjust PPM center would shift the end points, and likely cause your linkages to bind.

Ideally you start setting up your model by setting PPM center so that your servo horns are perpendicular to the linkage which will usually get you to some value that is neither 1500 nor 1520, then don't touch it anymore.

[rguptaca]

Ah, thanks.

[Daedalus66]

In the servo diagrams you would expect to see 1ms and 2ms giving about 45-50 degrees each way, not 90degrees.