OpenTx - Questions and Problems

[IanR]

Can anyone explain why, on Open TX 2.2, the switches shown on the simulator are in alphabetical order, and not in the order in which they appear on the transmitter (as was the case with previous versions)

I am finding it very difficult to get my head round the new layout.

Is there a way to change the look of the simulator back to how it was previously?

Thanks Ian

[Andy48]

Posted by IanR on 16/05/2020 11:51:02:

Can anyone explain why, on Open TX 2.2, the switches shown on the simulator are in alphabetical order, and not in the order in which they appear on the transmitter (as was the case with previous versions)

I am finding it very difficult to get my head round the new layout.

Is there a way to change the look of the simulator back to how it was previously?

Thanks Ian

I think this was done because of the escalating number of different transmitters OTX will work on, all with a different number and layout of switches..

No it cannot be changed back.

The switches can prove to be a bit of a weak point on FrSky gear and OTX, simply because of their versatility. It is also annoying that on the Horus transmitter only some switches are labelled.

BTW, while you have updated this far, why not fully update to 2.3?

Edited By Andy48 on 16/05/2020 12:20:12

[IanR]

Thanks for clearing that up for me, Andy.

When I start Open TX 2.2.3 I am asked if I want to update to 2.2.4 and I say no - I don't want to introduce any further possible complications. I should state that I am about to celebrate (?) my 70th birthday and am beginning to realise that this will come with not just "senior moments" but senior-rest-of-my-life. These days I have the attention span of a gnat - a sleepy gnat.

My only reason for upgrading to 2.2 was to be able to use lua on my transmitter in order to make changes to S6R receivers at the field, rather than waiting to get home and do it via the computer - otherwise I would have left well enough alone.

So, (1) is it worth updating to 2.3 for someone like me (who is not interested in telemetry) and (2) would I also need to update my X9D Plus?

Many thanks Ian

[Andy48]

Hi Ian, I'm older than you! I look on OpenTX as being part of keeping mind and body alive, and I enjoy a challenge. hey ho!

Yes its worth updating to 2.3, (not 2.2.4) and yes its essential to update both. Should not introduce any more complications than updating to 2.2.4. Telemetry is well worth it if only to monitor signal strength during flight (RSSI). Great feature after the first few tentative flights with a new model. Also really useful if you fly electric to monitor battery voltage and consumption.

In most cases updating makes little difference, except it irons out bugs and adds extra bits and pieces, some of which are really useful.

[IanR]

Thanks, again, Andy. I will update to 2.3 per your advice.

Ian

[GrumpyGnome]

Morning all,

I have an interesting conundrum. I am setting up a wing with elevons on my x9d+. As usual I have created a mix of aileron channel to elevator channel with a mix of 100%. Everything works in the right direction, but.......

If I input full up - both servos move in unison, with same travel

If I input full down - both servos move in unison, but the travel is not equal, the left aileron (assigned to the ele channel) stops at about 75% of the right aileron throw

Similarly, full right aileron works ok, but full left shows uneven throws.

All inputs are at 100%, no expo or diff, no offsets, all mixes are 100%, all outputs are at 100%.

I have tried different servos and receivers but seen the same behaviour. Interestingly, I can see similar behaviour in an older model, where I had swapped one servo and assumed the uneven throw was a result of that. I know, should never assume! I guess I never really noticed the effect in flight as I must have been making compensating stick movements.

Anyway, anyone have any idea of cause and/or fix?

TIA

GG

Edited By GrumpyGnome on 18/10/2020 06:45:38

[Ron Gray]

Have you tried re-calibrating the sticks?

[Attilio Rausse]

Do you use your computer to set up your transmitter?

[GrumpyGnome]

Hi Ron,

Yes, no change.

Hi Attilio,

No, programmed with the transmitter.

GG

[GrumpyGnome]

Hi Ron,

Yes, no change.

Hi Attilio,

No, programmed with the transmitter.

GG

[Peter Christy]

Posted by GrumpyGnome on 18/10/2020 06:45:01:

All inputs are at 100%, no expo or diff, no offsets, all mixes are 100%, all outputs are at 100%.

I suspect that is the problem - you are over-driving things!

Take a very simple mix, like a V-Tail or elevons. If you set the travel adjust to 100% AND the mix to 100%, when you move the stick diagonally, you will be trying to move the servo through 200%!

It ain't gonna happen!

Back in the early 70's, when I designed the very first "digital" mixer, I had a load of queries from customers complaining that the servos were only moving half their normal travel. As soon as I showed them that moving the stick diagonally caused one servo to move 100%, and the other not move at all, they had a "light bulb" moment.

Try setting the mixes to 50 or 60% and see if that helps.

--

Pete

[GrumpyGnome]

Thanks gents.

I will:

a) import to Companion, check and export

b) try recalibrating again

c) try reducing the mixes.

I will report back.

GG

[Bob Cotsford]

If all else fails, can you disconnect the servos and check that the left elevon really does move down as far as the right one freely and with no binding or obstructions to the pushrod or horn? Really, if you have both aileron and elevator mixed at 100% the fact that the outputs are set to 100 each way will clip the excess travel so neither servo should exceed that in either direction.

Have you switched to the channel monitor to check how far the channel output signal is moving at max stick deflection in both axis?

last thought - is the extended limits box ticked (model settings page)?

Edited By Bob Cotsford on 18/10/2020 10:55:52

[GrumpyGnome]

Morning,

As stated, I imported and exported to Companion. No change.

I recalibrated. No change.

I reduced all mixes to 50%. Worked fine but would have resulted in very soft responses. So, I kept increasing the mix %....... successfully reached 100% with no problems!

Problem solved but I really don't understand, so will try and replicate it on a new 'model'.

Thanks everyone.

GG

P.S. Bob - I managed to fix it before checking channel monitors.... I'll see what happens.

P.P.S. Still love OpenTx

[EarlyBird]

Morning GG,

This is interesting and quite opportunistic as I am looking at mixing for a V-Tail glider.

I just happened to see this -

Here

and as you see he sets the mixes to 50%.

I wonder if he has increased the throws mechanically.

The other thought is that as the mixes are at 100% and therefore the outputs will be clipped, as Bob said, he has the elevator as the primary control so if full up elevator is applied does this mean that there is no aileron added to one side? That is my guess and does it matter?

The biggest curiosity is that your problem is solved with no obvious changes, even more interesting.

Cheers

Steve

[GrumpyGnome]

Hi Steve,

Just checked, and you are spot on! I have resolved one issue and potentially replaced it with another. I will need to play some more.

Cheers

GG

[Peter Christy]

Posted by GrumpyGnome on 19/10/2020 05:09:01:

I reduced all mixes to 50%. Worked fine but would have resulted in very soft responses.

At which point it would be necessary to increase travel mechanically to get the necessary response.

I don't understand why subsequently increasing back to 100% didn't re-introduce the issue. In theory (and in practice, when I've done it!) the control responses will clip once you push them beyond a certain limit.

Its also worth remembering that OpenTx specifies its percentages in a different way to Futaba, JR, etc. On Futaba and JR, 100% is actually a bit less than 100%, and you can increase the travel adjust up to 125%. On OpenTx 100% means 100%, and you can't really go much beyond that.

For example, setting 100% travel on JR will give a pulse output that varies between 1.1 and 1.9 mS. This is to allow a small amount at each end for trim adjustments. Most servos are assumed to have a maximum travel from 1 to 2 mS, though most will go a little bit beyond this.

On the other hand, OpenTx, when set to 100% already gives a pulse out from .988mS to 2.012mS. ie: It is already trying to drive the servos to their limit. When setting up a model I usually set the inputs to 80 or 90% to bring them back into line with Futaba / JR convention, and not risk over-driving anything.

In view of the above, if you have the input set to 100% and then add (via the mixer) 100% of a second input, you will end up trying to drive a servo to 200% (!) with a pulse that goes from zero to 4mS! Not only is this physically impossible for the servo, but the system will not allow it anyway, and will limit the travel once it goes beyond the boundaries it can cope with.

The only other thing I can think of is that you have done something strange in the mix "multiplex" or "curve" functions, which can have a dramatic effect on the way a mix works. The default "multiplex" setting is "add", with options of "multiply" and "replace". Similarly, there are various options under the "curve" section. Its probably worth checking that you haven't accidentally set up something strange under there.

In summary, by setting both the travel and mixes to 100%, you are trying to achieve the impossible. One or both need to be reduced to keep everything within reasonable boundaries. If this results in insufficient throw on the control surfaces, then you will have to adjust that mechanically.

Best of luck!

--

Pete

[Bob Cotsford]

Extended limits will allow for 140% total output before clipping occurs but this needs to be used with care, you MUST set the Output page channel limits to a prevent the servo or control surface being driven past their mechanical limits allowing for the additional trim range on top of the stick movement. Longer servo arms are always an option!

However - on my Blink wing I'm using 50% on both aileron and elevator mixed for the elevons but on my V tail glider I've used 65% elevator and rudder mixed so that one does clip the output at extreme movements. Both models use 100 as travel limits in Outputs.

Edited By Bob Cotsford on 19/10/2020 11:34:15

[robert chamberlain]

People, somewhere out there, while surfing the web , I did see an add for "GO SLOW". which seemed to solve this issue. I will try to find it and report back,------------------- Bob

[MattyB]

Posted by robert chamberlain on 20/10/2020 04:31:11:

People, somewhere out there, while surfing the web , I did see an add for "GO SLOW". which seemed to solve this issue. I will try to find it and report back,------------------- Bob

Bob, slowing is nothing to do with this problem which appears to be an uneven movement of the servos, probably because of a setup mistake somewhere in the mixer. Even if servo slowing were helpful it can be enabled for any control in OpenTX, so there is no need for an additional device to be added to the model.