Throttle pulling down Rx

[ollie2893]

Made a bit of a weird experience today with my eLogger V3 (s/w V7.84) so I thought I'd ask...

I was rewiring my bird today. Weird thing was that when I connected the battery, my Rx would not boot. My MicroBeast, on the other hand, did - and it feeds only from the Rx. Mind, the MicroBeast never completed the boot coz there was no signal from the Rx. I worked out (after some while) that whenever I disconnected the throttle signal line (from my Rx), all was fine; whenever I connected it, all went bad. Now, I had torn the HV minus line to my ET from its EC3. I did not think too much of it - too many other building sites. But I did work out that when I pushed the HV minus back in, then the Rx would work with the throttle connected.

I should mention - although you will have guessed at this stage - that my throttle signal (a single wire only) is split into my ET (for recording). (The other two +/- lines of the Y-cable, incidentally, pull power from my BEC.)

I always assumed that our signal lines were + and that the ET would ground the LV throttle signal to the HV minus. So I could have accepted that the throttle recording may simply not have functioned with the HV minus ruptured.

I would like to understand what horrible things electric went on in my poor Rx while the ET did not have a minus (the plus was always connected to the flight-pack)?

Incidentally, my Rx feeds from a BEC that's connected to the same flight pack as the ET. This seems like a closed circuit. I am quite intrigued how the throttle recording works when the Rx is powered from a separate Rx pack. The throttle signal then connects - via the ET - the positive terminal of the Rx pack with the negative terminal of the flight pack. Is this wholesome?

[ollie2893]

Some more throttle weirdness I could do with some help with. When running Live Mode, the ET dashboard shows my throttle settings at 2x my input / 10. Problem is that the data read back from the recorder does not match to the values shown by the live dashboard. They should be live*10 but they come out higher.

Example: my ST1 sends out a throttle of 18%, the live throttle shows a reading of 3 but the data recorded in ST1 displays a reading of 65. So to work back to my input signal, I need to divide my recorded data by almost 4.

Except this does not follow either. My ST2 sends out 40%, the live dashboard shows 8 but the data recorder shows 100. So the error for ST2 is materially lower than that for ST1.

Anyone got any idea what's going on here? 100% throttle incidentally records 190 and shows live as 19, so no error at all. The error is exponential, in other words.

EDIT: Just notice that the min throttle value (for 0% input) shows in the data recorder as 30 (the live throttle pulls down to a proper 0). Divided by 10 this is a reasonably small error but it baffles me that the max throttle reading (of 190) should be right (-ish - should really read 200). If I had to pull all Y values down by 30, then my max throttle would come out at 160 - materially too low.

It really would seem like the data recorder would benefit from some throttle calibration. But how to achieve this?

[ollie2893]

Just realized that I can also turn on Live Mode in the chart display. When I do this, the live Chart data matches the recordings (*) but when I shuffle the chart aside so that I can see the live dashboard and the live chart at the same time, then the two show the same discrepancies I talked about above. What gives?

(*) Except that zero throttle now seems to show up at 45 in the live chart