Lvar read for FBW A320

[myles841]

Hi there,

I have an ACARS application and various users are reporting an issue that the park brake is no longer detected for the FBW A320 in MSFS.

I am looking to update the application (if possible) to read from the Lvars for the park brake which I believe is A32NX_PARK_BRAKE_LEVER_POS.

However, when doing so it always returns 0 regardless of lever position.

I am using the latest FSUIPC and Paul's FSUIPCClient DLL (3.2.7).

I have essentially been trying to get the value using FSUIPCConnection.ReadLVar("A32NX_PARK_BRAKE_LEVER_POS").

Any help would be appreciated. This is a C# application.

Thanks.

[John Dowson]

For c# questions using Paul Henty's dll, you should really post in Paul's sub-forum. I will move your post for you.

This can also occur if trying to read an lvar after opening a connection and before the lvar values have been received from the FS. To prevent this, you need to register for the update callback using the function
     fsuipcw_registerUpdateCallback
Lvars will be available to read once the registered callback function has been called.

If using a registered version of FSUIPC7, you (i.e. your users) can also try listing the available lvars and values using the Add-ons->WASM-<List Lvars... menu option.
This should give you a snapshot of available lvars and values.

Also, if using a registered version of FSUIPC7, it is possible to use the lvars-to-offsets functionality to populate a user offset with the lvar value, and then spoof the park brake position offset (0x0BC8) to the value held in the lvar offset. See the following post for details: 

 

John

[myles841]

Thank you for the information, that makes sense.

Hopefully Paul would be kind enough to provide an example of how to use fsuipcw_registerUpdateCallback with his library as I am struggling to find any examples for this.

I call FSUIPCConnection.Process before FSUIPCConnection.ReadLVar("A32NX_PARK_BRAKE_LEVER_POS") when loaded in the sim with a test harness application but still reads a 0.

EDIT: I just found this thread 

Ill have a look into this first. Am i right in thinking to use WASM you need the registered version of FSUIPC7? If so, I will relay this information to the users.

Thanks.

Edited July 21, 2021 by myles841

[John Dowson]

I have just noticed this:

4 hours ago, myles841 said:

I have essentially been trying to get the value using FSUIPCConnection.ReadLVar("A32NX_PARK_BRAKE_LEVER_POS").

That is the old method of accessing lvars via FSUIPC offsets. You should try the newer method using the MSFSVariableServices class. See 

 

John

[myles841]

Thanks John, I have successfully got it working using that post/WASM, I should have searched a bit more!

 

[John Dowson]

45 minutes ago, myles841 said:

Thanks John, I have successfully got it working using that post/WASM, I should have searched a bit more!

👍