Analog telemetry problem in 2.1.7

Post Reply
RightRudder
Posts: 241
Joined: Tue Jan 15, 2013 9:41 pm
Country: -

Analog telemetry problem in 2.1.7

Post by RightRudder »

I am having a problem getting telemetry from a D8RII+ Rx to work properly and there is another problem with transfer between the radio and PC in both directions. Although I can set up a sensor on either one, during the transfer, the source (set as A2) gets reset to ---. I have an openXvario on analog in A2 and a VFAS sensor on the digital telemetry port. The digital telemetry works fine. I have set up a sensor for vspd as a calculated with A2 as source, averaging with auto offset and filter both checked. I have similarly created a calculated sensor for Alt using Vspd as source, set to Totalize also with auto offset and filter. A1 and A2 show up with an auto discovery as ID F102 and F103 and instance 25 for both. I see them displayed correctly on Taranis. In Companion in the telemetry tab I have set the altimetry source as my calculated Vspd sensor and in the top bar section I have set Alt as the source for altitude. As stated if I burn these to the transmitter the source gets reset to --- but I can manually reconfig the vspd source to A2 and then both the Vspd and Alt fields in the telemetry page are populated with data. If I reset the telemetry I get zeros for altitude and vertical speed. When I raise the model up with my hand, the vario beeps and then settles but the altitude racks up to thousands of meters! How do I scale the analog data properly? What about the transfer problem? Am I doing something wrong?

Joe

User avatar
Kilrah
Posts: 11108
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Analog telemetry problem in 2.1.7

Post by Kilrah »

Hi,

You should adjust the A2 offset so that the reported value is 0 when not moving, and scale so it gives something more or less realistic as a vertical speed. Select unit m/s or ft/s, otherwise it will not be considered a valid vario source.

Note that ahis analog method is a "last resort" solution, it gives *something* but isn't really good nor precise.
RightRudder
Posts: 241
Joined: Tue Jan 15, 2013 9:41 pm
Country: -

Re: Analog telemetry problem in 2.1.7

Post by RightRudder »

I checked Auto offset. When I reset telemetry on the Taranis it does go to zero. But when the vspd goes to something like 0.5m/s the altitude climbs into the thousands in one second. How do I scale the value for A2?
User avatar
Kilrah
Posts: 11108
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Analog telemetry problem in 2.1.7

Post by Kilrah »

The Ratio parameter.
And you shouldn't use any function (totalize etc).
RightRudder
Posts: 241
Joined: Tue Jan 15, 2013 9:41 pm
Country: -

Re: Analog telemetry problem in 2.1.7

Post by RightRudder »

Are you sure your advice is correct? It doesn't seem to work. The openXvario is wired to average the PWM output and is compiled as vavg=vspd so it is putting out a voltage proportional to vertical speed. If I set the telemetry variable as alt with source A2 and it is not totalized then the altitude display acts like a vertical speed, ie when I lift the model up the altitude dispayed starts to increase but then decreases again without lowering the model. I can set it to calculated and totalize but then I lose the ability to scale the value as is possible when the telemetry value is set as custom instead of calculated.

Also what about the issue where the telemetry parameters set in companion are wiped out when the file is written to the radio or vice versa?

User avatar
Kilrah
Posts: 11108
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Analog telemetry problem in 2.1.7

Post by Kilrah »

Well firstly I'd need to correctly understand what you want - My understanding was you just wanted a Vspd value and vario tones.
Now with additional info it seems you're trying to get an altitude value out of that vertical speed?

There is nothing to do that in OpenTX. Indeed what you're looking at is an integrator, which "totalize" indeed implements part of, so playing with that is your best bet. You can try scaling down the Vspd with ratio so it becomes tiny, but then will be ridiculously imprecise.

The whole idea is flawed though, the oXs takes altitude and derivates that into a vertical speed with some filtering to remove fluctuations and noise a user wouldn't want to see, but that would be essential for an integration back into altitude to work. Supposing it was reliable in the first place which isn't the case given the limitations of the telemetry stream.
Even with everything "perfect" your altitude would likely suffer integration drift of a few meters per second which would obviously make it useless.

For the transfer error I'd need to know exactly what you've set up and what gets mangled, or even better a sample file to reproduce the problem.
RightRudder
Posts: 241
Joined: Tue Jan 15, 2013 9:41 pm
Country: -

Re: Analog telemetry problem in 2.1.7

Post by RightRudder »

Well the main thing for me is the operation of the vario. The altitude reading is a nicety but not essential. Maybe I'll scrap the idea but it seemed to work fairly well on my sky9x a few years ago. The other problem seems to just involve using A2 as a source for a calculated telemetry item. If I set it up that way in companion then when I copy down to the tx and then open up the telemetry page and look at the source for that item it got changed to ---. If I fix it back to A2 on the Tx and then read the eeprom back to the computer and then go take a look, it is again reset to ---.
User avatar
Kilrah
Posts: 11108
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Analog telemetry problem in 2.1.7

Post by Kilrah »

I can't reproduce the --- issue, so please send your eeprom file as requested.
RightRudder
Posts: 241
Joined: Tue Jan 15, 2013 9:41 pm
Country: -

Re: Analog telemetry problem in 2.1.7

Post by RightRudder »

Ok here is the file I just read from the tx. Notice how the calculated vspd source is --- but I had set in on the radio as A2. Same thing happens if I set it to A2 in companion and then go check it on the tx. Am I missing something here?
Spectre.eepe
(77.03 KiB) Downloaded 343 times
User avatar
Kilrah
Posts: 11108
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Analog telemetry problem in 2.1.7

Post by Kilrah »

Ah got it, thought you meant "vario source" got reset, not the sources for the calculated sensor.
Seems to be a bug in companion with the Average formula indeed.

But the "good" news is that it won't bother you because using Average as you are does absolutely nothing... It gives you the average of multiple sources at a given instant, so with only one source it always returns just that value. It's not a temporal averaging, that would be the "filter" checkbox on each sensor.
RightRudder
Posts: 241
Joined: Tue Jan 15, 2013 9:41 pm
Country: -

Re: Analog telemetry problem in 2.1.7

Post by RightRudder »

Ok good to know. Should I report that as a bug? I think you are one of the dev's ? So maybe you are already notifying Bertrand or whomever would be best to inform?

Let me know if I should do something. Thanks for your help.

Joe
User avatar
Kilrah
Posts: 11108
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Analog telemetry problem in 2.1.7

Post by Kilrah »


Post Reply

Return to “openTx for FrSky radios”