12many

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Hi,

I'm experimenting with atypical frame architectures & motor configurations.  This has led me to discover an unusual issue on the GCS Configuration / Outputs page.  Not exactly a bug, more of a undesired-behavior.  Steps to reproduce:

1. With at least two output channels enabled, set channel_1_max=1900 (default), set channel_2_max=1500 (updated value)

2. Check Link for both channels

3. Check Live Testing at bottom of page

4. Drag sliders.

Issue:  Sliders do not move in-sync.  Sliders at maximum do not result in 1900 / 1500 output as expected, they generate 1500 / 1500 output instead.

Should I bug this?

I'm trying to create proportionally biased outputs to compensate for different motors & props on a vehicle.  To simplify things, I'm running some 4S motors from the 6S power rail.  Setting max_output seems to be a good way to avoid over-driving these motors.  Is this advisable or is just trusting custom vehicle throttle curves the way to go?


« Last Edit: November 02, 2016, 12:04:58 am by 12many »

f5soh

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You want to test outputs, when you link outputs you got the same value.
Seems the expected result when you use the link option for calibrating escs or setting neutral together.

12many

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Thanks for responding so quickly f5soh.

At least to me, 'link' implies link by slider value (throttle percentage) not actual output value.  It's not a big issue, I can always set values manually not using Link and just line the sliders up visually.

Actually the second part is more important - can you comment on limiting MAX to scale back motor output?  I'm kind of assuming that the FC mixer will scale (LERP) output proportionally (0-100% throttle) to MIN-to-MAX (100-1500 in this case).  Is this a safe assumption?
« Last Edit: November 02, 2016, 12:05:26 am by 12many »

f5soh

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When you play in the Output tab you have direct access to the outputs, the Throttle has nothing to do here.

If you want something proportional / using mixers, try setting some "manual" stabilization in Flightmodes tab.

12many

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Sorry if the question was unclear.

Please correct me if I'm wrong but my assumption is that MIN/MAX values set in the Outputs page will be used in proportion to throttle level by the flight controller.  I.e:

    Default 100(min) / 1900(max) = 100Hz @ ~0%, 1900Hz @ 100% throttle
 but using 100(min) / 1500(max) = 100Hz @ ~0%, 1500Hz @ 100% throttle

In other words, throttle is liner-interpolated (scaled) at some point to operate within the specified min/max.

Is this assumption correct?  Unfortunately I don't have a tachometer to simply experiment and validate one way or the other.

f5soh

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I wonder how you obtain the µs <> Hz conversion.
Esc or GCS should not accept a min value set to 100µs.

The min/max values matches the values set/calibrated in Esc.

I've had similar issues with this.

IMHO when two sliders are linked, then moving it to min on one should move it to min on the other and same for neutral and max.

So if channel A is 1000 1500 2000
and channel B is 1200 1600 1700
then moving it to min of either should move it to A1000 and B1200, also around neutral they should be A1500 and B1600 and around max they should be A2000 and B1700.

This would be implemented as two linear scalings, where A1000 A1500 is matched to B1200 B1600 when in the lower range and A1500 A2000 is matched to B1600 B1700 when in the higher range.