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Posted by pressalltheknobs | Aug 22, 2017 @ 12:38 AM | 2,492 Views
Upgrading the XJT firmware. (2017-05-21 170317) fixes Q-X7 binding problems.

Wizard for QX7
Posted by pressalltheknobs | Jul 20, 2017 @ 10:32 PM | 2,835 Views
FrSky D16 Telemetry RXs...

This summary is for guidance only and may not be completely accurate. Check for manuals and firmware updates that may add features for the actual features supported.

XSR = CPPM and SBUS only
X4R = 4 PWM channels. CPPM support.
X4RSB = 3 PWM channels and SBUS. CPPM support
X6R = 6 PWM channels and SBUS
X8R = 8 PWM channels and SBUS

In combination...
x4R + x6R = 10 PWM channels and SBUS
2* x6R = 12 PWM channels and SBUS
x6R + x8R = 14 PWM channels and SBUS
2* x8R = 16 PWM channels and SBUS

Note: 1 You must disable telemetry on one or the pair. For the X6R and X8R this is a bind time configuration. For the X4R you need OpenTX 2.2 with the "bindopt" feature and updated XJT/RX firmware from March 2017 or later.
Note: 2 You can also use these with a FrSky SBUS to 4 PWM converter to the N + 4 PWM channels

FrSky D16 Non Telemetry micro RXs...

XMR = 6 PWM channels for micro use no telemetry
XM = SBUS only for micro use
XM+ = SBUS only for full range use

FrSky D16 Telemetry Stabilizing RXs

X6R = 6 PWM channels and SBUS
X8R = 8 PWM channels and SBUS

Note: X6R and X8R support D8 mode

FrSky D16 Telemetry Redundency RXs

R-XSR = CPPM and SBUS used in conjunction with another RX to get redundant receivers.
RX8R = 8 PWM channels and SBUS used in conjunction with another RX to get redundant receivers
RB 10 = 10 PWM channels and SBUS not a...Continue Reading
Posted by pressalltheknobs | Apr 21, 2017 @ 12:29 PM | 4,531 Views
Seems like it should be easy to just test the RxBat Telemetry value. The problem, depending on the version of OpenTX being used, is that telemetry values hold when telemetry is lost which makes it tricky to set up a good test. However, it turns out that telemetry values will test as FALSE when when telemetry is lost so you can use that fact to set a logical switch. You just need to a test a telemetry value in a way that will always be TRUE when there is Telemetry.

Here's an example...

The purpose of this is if you constantly arm, fly, land, disarm, and repeat on a single battery you don't want the timer resetting each cycle.

First bind the RX and discover the Telemetry.

Then a few Logical Switches
L1 A>x RSSI 0dB - The value here is a "dummy" test. RSSI should never go to 0 when there is telemetry available. You will hit the critical threshold first so this will always evaluate to TRUE when there is telemetry, However, once telemetry is lost it will evaluate to FALSE

L2 AND SF^ !L1 - used to reset the timer
L3 AND SFv L1 - used to start the timer

Then a couple of Special Functions, one for a throttle cut and one to reset the timer...

SF1 SF^ OverrideCH1 -100 enabled - this is a basic cut and stands in for any arm/disarm logic just to provide a working example
SF2 L2 Reset Timer 1

Then set Timer 1 to start on L3

The Timer will not start until there is telemetry and you arm.
The Timer will continue while you are armed or disarmed while there is...Continue Reading
Posted by pressalltheknobs | Apr 12, 2017 @ 07:48 PM | 5,265 Views
1) charge the battery
2.) go into the Radio Setup (Long Press Menu) and set the time and date and Default Channel Order.
3) from the Radio Setup, press Page to see the Version page and record it
4) press page a few more times to the Calibration screen and calibrate the sticks.
5) exit to the Model monitor Screen
6) Short Press Menu to get to the Model selector screen. the * marks the current model
7) Create a new model in slot 01 ...It should create using the default channel order you set in the Radio Setup. If there is one already you can edit that but it may have a different channel order. You can't delete the current model so you have to create one in Slot 02. Make that the current and so on.
8). Assuming you have receiver press Page to get to the Model Setup page and up or down to get the the Internal module settings..Select the correct protocol for you RX ..probably D16 if it is and X , D8 if its a D or VII.
9) Follow the bind instructions to bind your receiver. D16 uses the Receiver number to implement a model matching feature. It will default the slot number model slot number.

Other information here...

official OpenTX manual

good introduction to programing...

lots of useful articles but the organization of them is a bit out of control and in particular here...

a good Companion oriented reference of OpenTX 2....Continue Reading
Posted by pressalltheknobs | Feb 16, 2017 @ 01:45 AM | 5,706 Views
The "Throttle Trim Idle Only" magic checkbox changes the offset of the lower 25% of the range as the throttle trim is changed so min throttle varies with the trim from -100 to -75. However, max throttle stays at 100. The throttle curve is scaled to fit between the trim level and 100 so the full stick throw still acts.

A problem with the "Throttle Trim Idle Only" feature is that it is tied to the Throttle trim switch and doesn't move if you cross trim because it is implemented as a "magic" feature for historical reasons.

Partly to understand what the feature does and partly to provide a mix that can be used with any trim switch I worked out how to implement the feature using Mixes.

What is going on is that as the trim increases the offset of the CH line, the line weight is decreased to keep the max at (x=100% y=100%). The trim only affects the bottom 25% of the range so the factor for the offset and weight adjustment is half that and rounds down to 12 since we are only allowed whole numbers.

Since the relationships are linear we don't need custom curves but can just use weight and

[I3] Thr Weight (+100%) NoTrim
*= TrmT Weight(-12%) NoTrim Offset(88%)
+= TrmT Weight(+12%) NoTrim Offset(12%)

which appears to almost exactly duplicate the behavior of the "Throttle Trim Idle Only" magic check box. Note that trim has to be removed from all the mix lines so we don't double dip and get extra trim messing...Continue Reading
Posted by pressalltheknobs | Feb 01, 2017 @ 05:11 PM | 6,246 Views
Caveat: I don't yet own a Q-X7 but I do own a 9XD+. OpenTX works the same way on both except for some minor details. This "How to" was prepared using Companion 2.2 RC10 to get the Q-X7 screens but its all standard stuff going back to OpenTX 2.0 and before. There is a small chance that this does not agree exactly with a real Q-X7 which at the time of writing ships with a slightly earlier release of OpenTX 2.2. I strongly recommend you upgrade to a recent stable version of OpenTX at your earliest convenience. Refer to the for the latest news on new releases. OpenTX 2.2 is still in pre-release and release candidate are announced in the NEWS and you will not find it on the Downloads page. Once released it will no doubt be published there and I will update this note if I remember.

Q-X7 with OpenTX Rates and Expo
Adding rates and expo on the Q-X7 with OpenTX is fairly straight forward except for one gotcha (see the DANGER note.)

Assuming the default newly created 4 channel model which has 4 defined MIXES for the 4 channels which are controlled by 4 corresponding INPUTS that use the 4 sticks... Ail, Elv, Thr, Rud.

1. Goto the INPUTS page
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2. Select the Input you want to add rates and expo (usually Ail is the most important) to and "Insert Before". This is important.
3. Scroll to the Weight field. press the wheel to edit and and change the Weight field to say 60
4. Scroll the Expo number and set it to say 50 (Note. You may...Continue Reading
Posted by pressalltheknobs | Feb 01, 2017 @ 05:00 PM | 5,312 Views
OpenTX is unusual in using the term "Weight" where other systems...Spektrum and Tactic for example...typically use the term "Rate". Weight and Rate are the same thing as you point out.

Rates, as in "Dual Rates" are actually doing the same thing as "Rate" on a mix so while you may have found it confusing, it is correct.

In the simple case, a stick controls a channel proportionally. 0% stick gives 0% channel and 100% stick gives 100% channel. If the stick is y and channel is x then

y = x

and you get a graph like this ...
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The slope of a graph or its gradient is the rate at which y changes with x, hence the term "Rate" is often used in RC.

If you set a "Rate" you change the rate at which x changes with y so for a 70% "Rate" when the ail stick is 100%, the ail channel is only 70% or...

ail stick = 70% ail channel, which you can also write as y = 0.7 * x
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When you mix two channels you do so with a particular weight (or rate)

If ail weight (or rate) is 100% and you mix elv at 70% weight (or rate) then you get ...

ail channel = 100% ail stick + 70% elv stick or...

y= 1*ail + 0.7*elv

If you don't touch the ail stick leaving it at 0% and push the elv stick to 100% then the ail channel will go to 70%... essentially the elv stick is controlling the ail channel at a 70% "Rate".

Weight is probably a "better" term to use when combining mixes because it seems to...Continue Reading