Taranaphobia

[Biggles' Elder Brother - Moderator]

Thanks Chris - sorry about having to delete the post, but it was really throwing the page formatting!

Well done for bottoming it out at least we know the answer!

BEB

[Paul Nazaroff]

Posted by Biggles' Elder Brother - Moderator on 14/05/2014 16:02:28:

I think TH% just delays timer start until the throttle is above a certain percentage. The timer runs normally as far as I know.

BEB

TH% works as a percentage of throttle input. Idle throttle position will run the timer at 0%, half throttle will run the timer at 50% speed, and full throttle runs the timer at 100%. You have to set your timer by calculating how long your battery will last at full throttle. If you have an esc with a reasonably linear relationship of throttle position to power output then TH% will give a fairly accurate timing of capacity remaining. If the esc is not linear than a curve could be added to the throttle mix to make the timing more linear in relation to the stick input. A bit of trial and error is involved with the initial calculation for the timer setting. Don't forget to allow yourself some buffer. When the timer reaches 0 seconds you still want some battery capacity left. Lipo's do not like being totally discharged and unexpected problems can always occur just before the landing.

i find this a very useful feature.

Paul

Edited By Paul Nazaroff on 16/05/2014 11:36:17

Edited By Paul Nazaroff on 16/05/2014 11:37:43

[Rich too]

Posted by Biggles' Elder Brother - Moderator on 14/05/2014 13:59:00:

To answer you question Rich - no I don't have shares in FrSky, or any associated company, or any distributor of their products here, or in any other country. I have absolutely no route to any financial or in-kind benefit what-so-ever from Taranis, OpenTx or anything connected with them. Clear enough?

Frankly mate if your not interested that's fine, but I don't see why you feel obliged to chip in your negative views? Just accept, you're might not be interested - but some people are, OK?. If you don't want to play here then just don't read it and don't post here - its as easy as that.

BEB

Edited By Biggles' Elder Brother - Moderator on 14/05/2014 13:59:29

ok, take a chill pill - it was just a little bit of humour.

[FilmBuff]

Here's my 2p worth. It is very easy to create a simple model, but anything more advanced is certainly not intuitive.

Expo - easy enough.

Mixes - easily mixed CAR, but then I found that rudder did not work independently - only as part of the mix when operating the aileron stick.

None of this is complex - it just needs someone to produce a good "how to guide". Open TX for Dummies.

BTW - I hope we are being eavesdropped by the FBI or GCHQ. Taranis is also a very advanced Unmanned Combat Air Vehicle...

 

Edited By Biggles' Elder Brother - Moderator on 16/05/2014 13:37:22

[Eifion Herbert]

Just used Taranis for the first time for real, controlling a model in the air and everything. First impressions are that it's a very nice radio to use. The sticks are very smooth, and the model felt more locked in somehow. Now I admit this may be entirely subjective, and I, having spent money on a new radio am doing my best to convince myself it was a good purchase (I think we all do this a bit), but I honestly did feel that the model was responding quicker, and more smoothly than with my previous radio.

The vario / altimeter worked really well, all in all very pleased.

While setting the model up (Radian) I noticed the tail surfaces were binding, so I went to adjust the end points. I've done so from the Servos screen, then I realised I could have done it from the Sticks screen, or by adjust the weight of the Mixes. Does it matter? Is there a prefered or recomended way of setting end points?

Edited to add - just had a play in C9X - setting the servos to 50% weight, then the Sticks to 50% then the Mixes to 50%. I notice each one has an effect, so that you get 50% output then 25% then 12.5% output as you add the 50% weighting by three methods. I also notice that the "Servos" screen on the Tx is labelled "Limits" in C9X so is this the "right" place to set end points?

Thanks,

Eifion

Edited By Eifion Herbert on 16/05/2014 20:31:37

[Biggles' Elder Brother - Moderator]

Congratulations Eifion - nice one!

Yes I think the stick quality on the Taranis is very good. I have no doubt what-so-ever that the stick quality on say a Jeti is better - I've never tried a Jeti but I imagine its better! But hey its over 7 times the price! I certainly think the sticks on the Taranis are as good as any I've used on a mid range Tx such as my old Futaba 8FG for example. They certainly don't feel like "budget radio" sticks.

Regarding the successive halving thing - this is what I meant in the early posts in this thread when I said I view my Taranis in terms of "signal flow". Think of it this way:

Fingers->sticks->mixer->servos(limits)->control output

And you can see how the successive halving comes into being - if only half of the stick movement is passed to the mixer, and only half of that to the servo etc. - that's what you get.

OK - weights or limits? Well the real answer mate is "what ever you want", whatever you feel comfortable with! Its your Tx and your model - you do what ever works for you.

Now the purists will be apoplectic at that comment - so to save me from lynching here's a more "correct" answer! Strictly speaking weights (or throws, or rates) are used for a slightly different reason than limits.

You usually use limits when you want to be sure a servo can't move further than a set point. Mainly you'd want this for mechanical reasons - something might jam if you did, or you need a retract mechanism to positively lock, or you need to set the tick over idle point on an engine etc. Its important to realise that often in such circumstances the limits might be different at either end of the servo's travel - depending on the circumstances.

Weight adjustment is more related to controlling the plus/minus envelop a servo moves over. So here you want to control both directions to the same degree - thus, for example, cutting down the overall envelope both sides of neutral. You usually do this simply because you want to control the sensitivity and the envelop of movement - for example because if you have too much aileron throw you can't use the full stick range because doing so produces frighteningly fast rolls!

BEB

[Chris Bott - Moderator]

Posted by Biggles' Elder Brother - Moderator on 16/05/2014 22:24:30:

You usually do this simply because you want to control the sensitivity and the envelop of movement - for example because if you have too much aileron throw you can't use the full stick range because doing so produces frighteningly fast rolls!

BEB

 

Or indeed because you can't use full stick range because doing so hits the limits you've had to set up to save stalling the servo.

EDIT ADDED HERE - The following is incorrect (in fact I may well delete it later)

i.e. If full stick produces 40 deg of movement, but the engine barrel hits the stop at a servo movement of 30deg, you might set a limit at 30 deg, (or a tiny bit less).

Setting just an endstop though, would mean that the endstop happens with the stick only 3/4 of the way down.
So you'd probably decide to reduce the mix percentage so that you reach the limit at or around the end of stick travel.

You could do this by just adjusting the mix percentage, but then you can run into trouble with stalling servos if more than one input can move the servo.

Edited By Chris Bott - Moderator on 17/05/2014 07:46:23

[J V R]

Reading this thread with interest, the way I look at the % are, on the sticks page I set maybe 80% then on the mixer page I then have say 100% of the 80% available, that's my system, not sure if it's the right way to look at it though.

JVR....

Edited By J V R on 16/05/2014 23:21:06

[Biggles' Elder Brother - Moderator]

Posted by Chris Bott - Moderator on 16/05/2014 22:42:57:

Posted by Biggles' Elder Brother - Moderator on 16/05/2014 22:24:30:

You usually do this simply because you want to control the sensitivity and the envelop of movement - for example because if you have too much aileron throw you can't use the full stick range because doing so produces frighteningly fast rolls!

BEB

Or indeed because you can't use full stick range because doing so hits the limits you've had to set up to save stalling the servo.

i.e. If full stick produces 40 deg of movement, but the engine barrel hits the stop at a servo movement of 30deg, you might set a limit at 30 deg, (or a tiny bit less).

Setting just an endstop though, would mean that the endstop happens with the stick only 3/4 of the way down.
So you'd probably decide to reduce the mix percentage so that you reach the limit at or around the end of stick travel.

You could do this by just adjusting the mix percentage, but then you can run into trouble with stalling servos if more than one input can move the servo.

I may be misunderstanding what you're saying here Chris - but if you mean what I think you mean, then I'm not sure C9X agrees!

I thought the same as you when I was making my post on this above, but I wasn't 100% sure - so I tested it on the simulator. First set the weight at 50% - and as you'd expect 100% stick movement gives 50% channel output movement - no "dead zone" at the end. Now set the weight back at 100% but alter the limits to plus/minus 50% - the same throw. Now test with the simulator and,...its exactly the same - again no "dead zone" you don't run out of channel output before you run out of stick movement. I haven't tested this on the actual Tx - but that's how the simulator reads it.

BEB

[Chris Jones 7]

Posted by Eifion Herbert on 16/05/2014 20:25:17:

Just used Taranis for the first time for real, controlling a model in the air and everything. First impressions are that it's a very nice radio to use. The sticks are very smooth, and the model felt more locked in somehow. Now I admit this may be entirely subjective, and I, having spent money on a new radio am doing my best to convince myself it was a good purchase (I think we all do this a bit), but I honestly did feel that the model was responding quicker, and more smoothly than with my previous radio.

I don't think your wrong on this Eifion, I noticed the same thing when I switched from a DX8 to a Taranis. Somehow everything just flew "better". Not sure what it is but everything from an indoor foamy through multirotors and helis to a DLG was just nicer to fly.

Chris

[Chris Bott - Moderator]

Eifion - I've put this feeling down to the fact I'm flying more now I have the Taranis and therefore I'm getting more practice. But maybe you have something there, who knows?

BEB - You are absolutely right, the limits settings do indeed seem to reduce the servo throw proportionally, how clever is that! Their use then, I'd think, is purely to set the ends of throws of the servos no matter how many different mixes you have to that servo. (I've added a note to my post above).

[David...]

Taranis has a resolution of 4096 steps, that's 4x more than a standard Tx some spektrum have 2048. Zhou would notice the increase in resolution IMO. We used to pay (last year) a lot of money for high resolution radios, not now though!

[Eifion Herbert]

There might be something in the resolution and latency thing after all then. I'd always agreed with the received wisdom that if you weren't a competition level pilot you wouldn't really notice, but I guess we can't all be wrong.

Another question - do I get Rx voltage an RSSI warnings by default or do I need to configure them?

[David...]

With a telemetry X8R Rx you get Rx voltage and RSSI as default.

[Bob Cotsford]

You'll get them with DX8R Plus series receivers too.

I still wonder about the 4096 resolution - the sticks move through about 60 degrees, so each degree represents 4096/60 = 68 and a bit steps per degree.

If I'm honest I doubt I could detect a movement of 1 minute on the stick, in fact some days I doubt I'd notice a resolution of a couple of degrees per step!

What I can see is that higher resolution allows you to use greater rate and servo limit reductions without loss of significant precision.

Edited By Bob Cotsford on 18/05/2014 10:44:35

[Chris Bott - Moderator]

I think all FrSky telemetry receivers give RSSI and Rx voltage by default.

It's easy enough to check in their specifications

Some, like D8R-II Plus, have two analogue voltage ports. The Rx voltage is measured using one of these ports, via a plug in link. You can remove this link and use the analogue voltage port for something else if you wish.

[Bob Cotsford]

Chris, the only exception to that I'm aware of is that earlier D8R (edited) receivers need an external voltage divider supplying one of the analogue inputs in order to get a voltage reading back to the transmitter.

Edited By Bob Cotsford on 18/05/2014 11:39:58

[Chris Bott - Moderator]

That's not a Rx I've heard of Bob, I'll have to add it to my list. Is it available to purchase anywhere?

I know some of the older telemetry receivers ONLY feature RSSI and Rx volts, they have no ports to plug in any external sensors.

It looks like the little indoor one with the tiny servo connectors is the same, although I have no experience of that one.

[Eifion Herbert]

I can see I have data for Rx voltage and signal strength on the Taranis screen when it's talking to the X8R. But will it tell me by default if these values drop too low, or do I need to configure an alert in the custom functions screen?

[Bob Cotsford]

oops, spurious 'X', the early D8Rs (v1?) didn't have Rx voltage and needed a voltage divider to feed a proportion of the Rx supply back to one of the two external analogue ports, then with V2 an input sense was built in and those receivers only had one external analogue port free. Finally the D8R-II Plus went back to two external analogue ports with A1 being fitted with a bridge to enable the internal voltage divider, or the bridge can be removed to allow using it as an external analogue input.

I have an unused example of the little VD5M in front of me, the destructions say it can be bound to a telemetry system but it's one-way only - no telemetry so while it will work with the Taranis there's no rx supply or RSSI display.

 

Eifion, I think you set your 'low' and 'oh Poo!' warning levels on the telemetry page for the model.

 

Edited By Bob Cotsford on 18/05/2014 11:42:43

[Biggles' Elder Brother - Moderator]

Eifion, my understanding is that warning levels are set by default to "oh that's a bit low" and "Opps! I'd land now if I we're you" levels. You can change them from these values - but they are the default. I can't remember the exact numbers for them (and I can't check at the moment), but something like 50 for the first and 42(?) for the second spring to mind? One question that springs to mind is what is the nature of the warning?

I ask because yesterday I was doing what was a "Taranis maiden" - ie the model had flown before but this was its first time on Taranis - when out of the blue, in mid flight, the Tx said "forty eight" to me! At first I was a bit puzzled, forty eight what?

Then it dawned on me - was this a RSSI warning? I intend to try to trigger a RSSI warning in the workshop (with a bit of tinfoil) to see what the Tx does!

BEB

[john stones 1 - Moderator]

You have me confused now lads I don't have a set yet, nor is it putting me off. How can you be getting weak signal indicators on 2.4 ? I thought it hopped about to cure this and make it safe ? maybe I missed something or failed to understand. Has it already hopped whilst it's telling you ? I still fly 35mhz so sorry if it's a daft question.

John

[Fatscoleymo]

John,

RSSI is Receiver Signal Strength Indicator. So it's high (strong) when it's close to you, and weaker as it gets further away, or something is in the way. So nothing to do with the 2.4 signal being locked on to the receiver, just an indication of the strength of signal the receiver is getting from the tranny. I've not yet had a low signal indicator while flying, and it's not something to worry about. Better to know it's getting a bit risky than just lose control with no prior knowledge.

Steve

[Bob Cotsford]

or to put it another way, frequency hopping is an attempt to avoid interference from 'other' transmitters, RSSI is something else entirely and tells you how strong the signal is ie are you getting near the limits of it's range. 2.4 still has the physical limitation of reducing signal strength with distance regardless of whether it's frequency hopping or spread spectrum.

[john stones 1 - Moderator]

Right lads, thanks

John