TX16S "auto detect format" on DSM?

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ThatVWguy
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TX16S "auto detect format" on DSM?

Post by ThatVWguy »

Hi,

I'm curious to know if the signal range conversion from OpenTX to Spektrum is handled "visibly" or if the magic happens behind the scenes similar to the channel re-mapping.

I was setting up a Blade 180 CFX (2014ish model) and found posts regarding OpenTX (via Taranis) and Spektrum channel output ranges being different. The documentation confirms this and insists if the "autodetect format" box is left checked, that the transmitter will output -100 to 100 within the Spektrum scale of 1100us to 1900us. However, the monitor channels don't reflect this.

Since the documentation of others suggested setting the output limits to -76.5 to 76.5 where Spektrum asks for -100 to 100, I did that. Then realized I wasn't getting to my 3rd headspeed output. Checked again and found somebody mentioning needing to use 85 for travel limit of throttle achieve the "above 100" Spektrum transmitters use. I tried that and still couldn't get to high head speed. I set the limit to 100, still no joy. When I enabled "extended limits" in model setup, and set the output travel limit to 110, I was able to get to the high head speed. This seems to suggest the "us" output is indeed scaled, but doesn't reflect in monitors. I'm curious if this range is automatically specified for all channels, or just select channels. Reason is, with all the other channels limited to 76.5 travel ends (- and +) the swash plate on the heli maxes out, for example, if at middle pitch I apply full "up" (back) elevator, then lower pitch, the swash plate starts to level off as I increase negative collective near the ends.

Although not scientific (I don't have the tools or instrumentation to compare transmitter outputs as interpreted by the flight board), I bound the heli back the 180 CFX and noticed this "swash limit" seems to be more easily reached (or starts flatten out sooner) with the TX16s if I set the limits to -/+100.

Come to think of it, I don't recall checking to make sure both TXs were set to high rates while conducting this unscientific test. But now I'm still wondering if what I researched for setups from forum posts dated 2014, if this "autodetect format" was developed after that time...

TL;DR version. Does the "autodetect format" handle the "us" output deviation between OpenTX and Spektrum expected "inputs" invisibly/behind-the-scenes? Does it apply to ALL channels?
Transmitter is V2.3.9
Module status shows: DSM 2 11ms (though the 180CFX manual specifies 22ms, I tried that and noticed about half a second latency, so went back to 11ms) V1.3.1.36 AETR.

And now the ultimate in Lazy, does anybody have an OTX file I can peruse setup specifically for the older Blade 180CFX, preferably with my TX firmware versions, and knows it flies as it should, dual rates included?

Thank you kindly for any feedback.

-Ron

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Kilrah
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Re: TX16S "auto detect format" on DSM?

Post by Kilrah »

The module does the pulse scaling unless you tick the checkbox that disables that. It's not related to autodetect.
ThatVWguy
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Joined: Mon Apr 12, 2021 1:25 pm
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Re: TX16S "auto detect format" on DSM?

Post by ThatVWguy »

Thank you for the quick response Kilrah. Honestly was expecting an e-mail informing me the post went up, may have gone to spam so I'll need to check that..

Anyway, what then does the "autodetect format" do?

And is the pulse scaling supposed to be reflected in the "Channel Monitor" screen?
I tested rudder and aileron with the different output limits, and got the results as follows:
Ail: Weight - 100; output limits - 76.5; output us - 1891 (the system seems to "round" the numbers and displayed 76%)
Rud: Weight - 100; output limits - 100; output us - 2012

Should I just assume that the module is sending out the documented 1900us even though the output monitor reflects 2012us on the Rud channel?

-Ron
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Kilrah
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Re: TX16S "auto detect format" on DSM?

Post by Kilrah »

The channel monitor doesn't know what the module does, it displays what the radio puts out, what happens afterwards is out of its purview.
Autodetect is about the module finding out from the receiver what DSM variant it needs to use to talk to it instead of you setting it manually.
ThatVWguy
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Re: TX16S "auto detect format" on DSM?

Post by ThatVWguy »

Kilrah, Thank you!

That confirms it then. Although I haven't looked for change logs, I take it the "old" information I found was from before the modules would automatically do the output conversions, or they must have had the equivalent of "Enable Max Throw" by default.

For my use, with any of my DSM/Spektrum products, I will leave "Enable Max Throw" disabled, but allow extended limits, and this will allow me to use the same "servo travel limits" and settings listed in the models' manuals.

krysly
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Re: TX16S "auto detect format" on DSM?

Post by krysly »

ThatVWguy wrote: Wed Apr 14, 2021 2:07 pm Kilrah, Thank you!

That confirms it then. Although I haven't looked for change logs, I take it the "old" information I found was from before the modules would automatically do the output conversions, or they must have had the equivalent of "Enable Max Throw" by default.

For my use, with any of my DSM/Spektrum products, I will leave "Enable Max Throw" disabled, but allow extended limits, and this will allow me to use the same "servo travel limits" and settings listed in the models' manuals.
Hi Ron,

i actually have the same challenge and try to understand it.
Could you provide me your openTX File for the Blade 180CFX with the settings which works for you?
That would be great.

Many Thanks
Christian

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