MobiFlight Community Support

Hi

On my previous build i had digital displays showing GS, altitude (above sea level & altitude above ground) and actual heading (not autopilot).
These were all preset extractions on Link2FS.
Since switching to Mobiflight I have been unable to recreate these readings.
Links2FS Extractions:
<D = Altitude above sea
<E = Altitude above ground
<J = Actual Heading
<O = Ground Speed

Could anyone spread some light on the offsets & maths if required to get these results?
These worked on the Standard Cessna 173, A2A 182, PMDG 737NGX in FSX & P3D v4.

I have searched and test several different offsets but without success.

Many Thanks
Phil

Hi
Basicly i recommend to check the FSUIPC Offset Lists ..... These are located in the Sim Folder..... There Subfolder "/Modules/FSUIPC Documents/ "
For example the "FSUIPC4 Offset Status.pdf" File include all standard stuff you need for your request.

In this File use SEARCH ( STRG-F) and type for example "gorund speed".
You will find all you need !

Ground speed:

02B4 4 GS: Ground Speed, as 65536*metres/sec. Not updated in Slew
mode!

Here recalculation is needed.... I not do this myself so you must test....
At first Value divide through 65536 (cause there is written the raw value is 65536 multiplyed.
Then you got "meters per second" .....
If you Multiply by 3600 ( Number of Seconds in a hour) you got Meters per Hour .
Finaly you like Knots .... 1852 Meters are a Nautical Mile..... 1 Mile per Hour is a Knot ..... So if you divide the meters/sec throug 1852 the result is GS in Knots.
$/65536*3600/1852 ....
If you combine this to a multiplication then my result is "2,96607E-5" ( Rounded and i hope i didi it right)
So try out in Mobiflight the Transform $*2.96607E-05 (NOTE... The decimal must be a POINT ... Not the Decimal Sign IMPORTANT)

(I hope that was correct. Normaly i try out those things myself.... PMDG give you a GRD Speed on the PFD...... Simply make this calculation and check there if your result is nearly the same. "Maby" i did a logical issue.

**************
For the Other things the way is the same.....Search - Read - Calculate

Many thanks,

I now have most of this working, just one query.
I have:
radio altitude (altitude above the ground)
Ground Level (altitude of ground)

is there a way in mobiflight to add these 2 results together to get Altitude above Sea level into one?
I couldn't find an offset to get the altitude above sea level.

Many thanks

Phil

Hi Phil,

Altitude above sea level is an independent term. Search for QNH in the documents.

Radio altitude is often used for landing for the decision height. The AP will callout the minimums.

Hi Stephan

Many thanks, having searched altitude in the list and trying all offsets. I decided it was 2 offsets added together.

QNH (thank you for pointing that out). This works perfectly

Is there actually a way of adding to offset results together? (just curious)

Also

can i add a switch/button to change a display from one offset value to another? (Switch doesn't do any events, just on or off)
(if switch is OFF display QNH, if switch is ON display Ground Clearance)?

I had this in my previous arduino programming (if (digitalRead(SWITCHPOS1) == HIGH) {HCMAX7219.print7Seg(...etc.)
I'm sure it will be possible but I'm struggling to find a way

Many thanks
Phil

Hi Phil,

at first I have to understand what you mean with adding...
You tell it after also...

Wikipedia:
QNH is a virtual pressure that is calculated so that when set as a reference pressure on a standard atmosphere calibrated altimeter, it will be displayed at the station height above sea level at standard temperature (15 ° C). (Quotation help for QNH: English Nautical Height.) The unit of measurement is hectopascal hPa (in the USA inch Hg).

Another term is the QFE. If you set your altimeter to 0 (zero) feet then you can read off the actual pressuration for your present height. So if you set the present altitude (in feet) on your altimeter, you can read out the QNH.

To your question: Yes, that is possible with MobiFlight.
You need 2 configs for your 7-segment-display and every config needs a precondition, so that alway only one config of these two is active.
First precondition is if your switch is on display QNH
Second precondition is if your switch is off then display ground clearance or vice versa.

I'm very sure that when pizman read this, he can explain it much more better than I. So stay tuned

Hi Stephan

Thanks for your reply,
I have my 2 configs, but i can't see the switches in precondition
I have set them up as buttons but no event/offset/macro as I don't want the switch to do anything in the sim, just to switch my display.

Just discovered my heading is not working correctly having moved to a different airport due to magnetic variation.
actual heading shows (0580)= 344º, magnetic (02A0) = 331º but the true heading on compass/ runway direction is 13º (which = offset value 0580-02A0), but i can't see how to subtract one variable value from another.

Kind Regards

Phil

Hi

Lots of questions... This will get a long Posting

About the 2 Configs for your Display.....

Your right.....
Mobiflight not allow us to "read" a Switch Position (Pin Status) for a precondition.
The "precondition" MUST be a existion Output Config..... And Those Configs can only read a FSUIPC Offset.
Its not possible to check a Pin like in your posted Code Part from the Arduino IDE.

So there are two ways.....

1. You use a existing Offset Information as a idicator.
For example you can say..... If your Gear is down ( So your on the Ground or in departure or final aproach) then Display should show Value A .... If Gear is UP then it should show Value B .
This is verry usefull for example in the Radio. Hear you can say if Active Microphone is set to Com1 then show Com1 Frequency on Display..... If active is Com 2 then show Com2 ..... If Active is ADF then show ADF and so on.

****
2. Using CUSTOM Offset ! ( Thats what you need pretty sure)
In FSUIPC exist "free" Offsets for personal use. This Offsets are "0" Zero at Systemstart and can be written and read by the User. For Example Offset 66C0 ( 1 BYte INT)
If you make a Input Config for your Switch ( On OFF Switch on a single Pin) with Press.... Write Offset 66C0 1 Byte to "1" and Release.... Write Offset 66C0 1 Byte to "0"

Now THIS Offset is 1 or 0 whitchever your switch is used....
Now you make a Output Config (without device) that Read exactly this Offset.
And THIS Config now is used as a precondition for your 2 Configs of the Display.
The ALT Value should be shown aslong this Readout Config of Custom Offset = 0
The QNH Value should be shown aslong this config is "1" .

*********


About your Altitude and Heading.

You must know what you need and what you want

As Stephan said.... There is not one Altitude... There are multiple....
Alt over GRD .... Alt over Sealevel in Standarf Atmosphere ..... Alt over sealevel in real atmosphere ..... Altitude from Ground in relation to sea level .... Radar Altitude ..... GPS Altitude .

Same like Heading/CRS.
You got magnetic North , geographic north. Heading ...Noseposition in releation to crosswinds and so on.

Finaly Speed.
there is True Air Speed , Indicated Air Speed , Speed over ground , Speed with or without wind factor and so on.


Summary.... Some Values can be readout directly on a Offset.... Others must be calculated with multiple offsets ( as you said) .
Its not possible to do that with Mobilflight.... We can NOT say Offset A minus Offset B for example.
BUT: Normaly we not need such Values. In a real Aircraft you have only basic Informations..... And all those standard Informations are available directly !

Thank you for spending time replying to my questions.
When directed by atc to turn right to 90º that is Magnetic Heading?
This is figure I'm wanting to display (the direction of the nose of the aircraft) to match up with runway headings etc. (I use this as a digital compass)
As far as i can see:
02A0 2 Magnetic variation (signed, –ve = West). For degrees *360/65536. Convert True headings to Magnetic by subtracting this value.
0580 4 Heading, *360/(65536*65536) for degrees TRUE.

But this isn't possible to do in mobiflight. Is it possible to add this feature in the future?

Kind Regards

Phil