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

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.

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

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.

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.

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)

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