Override CDI

[MDChase 6]

Gents,

 

       Does anyone know how to override the FSX CDI and Obs Variables like the RealityXP GPS' do, all I want to do is inject my own deflection and course variables so any plane can utilize my FMS as opposed to creating my own HSI.

 

Thanks

 

-Matthew Chase

HC-130H Pilot, CGAS Barbers Point

[WarpD 824]

Sure, simply hack FSX and determine the memory offset in FSX of the variable.  Once you know that, simply write your value to that memory offset.

[MDChase 6]

Ed,

 

  Thanks for the response, I have built a .dll for my data but I'm not really sure what hacking to find the offset entails although I am guessing this is the same thing FSUIPC does. Thanks for your help.

 

-Matt

[WarpD 824]

FSUIPC states that the value can not be overridden.. for what it's worth.

 

That means that Rxp is probably running a pretty heavy hack to get around any "protection" that FSX has for that variable.

[mgh 89]

Many FSX variables are read only because they are determined by the geometry/physics at the time. For example, the underlying bearing from a VOR variable depends on the relative positions of the aircraft and navaid.

[n4gix 4,947]

David Drouin's UNS-1Fw FMS writes a custom variable published globally as (L:UNS CDI NEEDLE,number) that may be used instead of the default (A:HSI CDI NEEDLE,number) in the HSI. The HSI CDI NEEDLE variable will switch between NAV1 and GPS as a source depending on the GPS DRIVES NAV1 variable.

 

In his control code, he can set the value of his (L:UNS CDI NEEDLE,number) variable to use either the NAV1 signal source, the GPS signal source or his UNS signal source.

 

In pseudo-code:

 

if (source) = 0 and (A:GPS DRIVES NAV1,bool) = 0, then (A:HSI CDI NEEDLE,number) (>L:UNS CDI NEEDLE,number)

 

if (source) = 1 and (A:GPS DRIVES NAV1,bool) = 1, then (A:HSI CDI NEEDLE,number) (>L:UNS CDI NEEDLE,number)

 

if (source) = 2, then (myFMSdeviation) (>L:UNS CDI NEEDLE,number)

[MDChase 6]

Thanks for all the help guys, I've already built a .dll (after much struggle since I'm going through my C-130 type rating right now) that I can send variables to XML gauges so I'll just write my own custom HSI I was just hoping for a more elegant solution so I could distribute my FMS (runs on tablets) so everyone could utilize it. Pretty proud of it so far it's my first step in to design and it has a fully updating navdata and is pretty versatile. Basically I calculate the cross track error course and distance on the app then feed it to my dll so it can be used in the simulator.

 

-Matt