Can I use lua to set a control based on the state of another control

[DaveDewhurst]

What I want to do is this

(I haven't tried it yet beyond checking the log to make sure the controls can be recognised)

 

1. When the AP is switched on either by the "z" key or the button in the VC, switch the Yaw Damper On

2. When the AP is switched off either by the "z" key or the button in the VC, switch the Yaw Damper Off

 

I need to be able to differentiate between AP on and AP Off rather than just recognising the key press as depending on the initial condition of the AP I need to know whether to switch the YD on or Off

 

So something like

if AP_Master == On and YD == Off then
set YD on
elseif AP_Master == Off and YD == On then
set YD off
end

Is that doable, before I start trying

 

If you're interested Im trying to workaround an issue the Alabeo C400 has where Activating the AP turns on the YD but deactivating leaves it on.

 

Thanks in advance

 

Dave

[Pete Dowson]

What I want to do is this

(I haven't tried it yet beyond checking the log to make sure the controls can be recognised)

 

1. When the AP is switched on either by the "z" key or the button in the VC, switch the Yaw Damper On

2. When the AP is switched off either by the "z" key or the button in the VC, switch the Yaw Damper Off

 

I need to be able to differentiate between AP on and AP Off rather than just recognising the key press as depending on the initial condition of the AP I need to know whether to switch the YD on or Off

 

States of things in FS are CHANGED by controls, but those are simply messages passed to FS to obey. They are just transient.

 

You need to check the current state, which is accomplished by reading the appropriate offset. All offsets for default aircraft (and used by many add-ons too) are listed and described in the List of Offsets document in your FSUIPC Documents folder. Note however that some add-ons (eg especially PMDG) implement their own methods with their own autopilot and you need to find the right way to get this information for your target aircraft.  I have mapped the PMDG 737NGX and 777X offsets into FSUIPC and these are also documented for you (you have to enable the service in the PMDG settings someplace first). But other aircraft may be more difficult, and may even require reading of LVars instead. Searching the User Contributions subforum might help.

 

The facilities to read (and write) both offsets and LVars are included in the ipc library for Lua plug-ins, so, yes what you want to do is clearly "doable". You'll want to use event.offset to call a function based on changes to the A/P status, and have the plug-in loaded automatically, perhaps via an [Auto] section in the INI file. You can have different ones for different aircraft loaded by Profile-specific [Auto...] sections.

 

Pete

[DaveDewhurst]

Got it, I think (well it seems to work) :razz:

--Lua file to automatically disable the Yaw Damper when the AP is disconnected
--and enable it (to mirror the VC button) when z is pressed
--Dave Dewhurst

function setyawdamper(offset, AP_Master)
    Yaw_Damper = ipc.readFLT(0x0808)
	if AP_Master > 0 and Yaw_Damper == 0 then
	ipc.writeFLT(0x0808, AP_Master)
    elseif AP_Master == 0 and Yaw_Damper > 0 then
	ipc.writeFLT(0x0808, 0)
    end
end

event.offset(0x07BC, "FLT", "setyawdamper")

Oddly, I was expecting ON == 1 and OFF = 0

but on seemed = 1.405......e-45

so I just set it equal to AP_MAster which was the same value when on

 

Thanks again, it took less time than I thought

 

Dave

[Pete Dowson]

Got it, I think (well it seems to work) :razz:

--Lua file to automatically disable the Yaw Damper when the AP is disconnected
--and enable it (to mirror the VC button) when z is pressed
--Dave Dewhurst

function setyawdamper(offset, AP_Master)
    Yaw_Damper = ipc.readFLT(0x0808)
	if AP_Master > 0 and Yaw_Damper == 0 then
	ipc.writeFLT(0x0808, AP_Master)
    elseif AP_Master == 0 and Yaw_Damper > 0 then
	ipc.writeFLT(0x0808, 0)
    end
end

event.offset(0x07BC, "FLT", "setyawdamper")

Oddly, I was expecting ON == 1 and OFF = 0

but on seemed = 1.405......e-45

so I just set it equal to AP_MAster which was the same value when on

 

Oh dear.  Very few offsets are FLT (32-bit floating point). Where they are it says so. 07BC is just a UD (unsigned double word), i.e. a simple number, and is most certainly either 0 or 1.

 

Same for the yaw damper.

 

Pete

[DaveDewhurst]

Hmm,

Ill re read what I read that made me think it was a float and try again.

Thanks for the extra pointer

 

Dave

 

EDIT, yep it was me reading things wrong (nothing new)

changed them to UD and can now set the values as 0 & 1

 

Thanks

Edited January 8, 2016 by DaveDewhurst