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jpcambre

LVAR list

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Is there a list for LVARS and what they control for this plane?

 

I would like to control the AP altitude with a knob.

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Got some LVAR values from my own research.

 

Display Altitude Value = DC8_ALERT_KNOB

You can change the value of the LVAR (increase/decrease by 100) and it will change the Altitude flawlessly.

 

Display Autopilot V/S Value = DC8_VS_WHEEL

Changing this value seems to be more problematic. Some combination of changing the LVAR and the default Autopilot V/S value. I am using FSUIPC AP V/S Value (FSUIPC:0000:07F2) but it is not without problems. If there is a better way to change this I would like to know.

 

Display Heading Value = AUTOPILOT HEADING LOCK DIR 

You can change the value of the LVAR (increase/decrease by 1) and it will change the heading flawlessly.

 

NAV1 Course only seems to be changed via the default value. I am using FSUIPC NAV1 OBS (CRS) (FSUIPC:0000:0C4E) to change the Course flawlessly.

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On ‎12‎/‎31‎/‎2018 at 12:32 PM, jpcambre said:

Is there a list for LVARS and what they control for this plane?

 

I would like to control the AP altitude with a knob.

 

Can you be more specific about what you want to control? The autopilot has no altitude capture function. If the VS wheel is set to zero it will set altitude hold to your current altitude.  Otherwise, use of the vertical speed mode will se the FSX altitude hold to zero or 60000 feet as required because vertical speed hold won't work unless the sim has a target altitude lower or higher than the current one. 

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I just wanted to change the altitude alerter with a knob. Which I did figure that out in post 2. I know that doesn't actually control the altitude capture, it's just an alerter.

 

Right now I'm just trying to figure out the vertical speed. It looks like the actual wheel in the plane is controlled using the LVAR DC8_VS_WHEEL, but this does not control the actual vertical speed function as it is using the default autopilot function. But the wheel still needs to move because as you said when the wheel is set to zero it sets the plane in altitude hold. So if you change the default vertical speed variable, nothing happens because it's still locked on altitude hold.

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When you move the VS wheel, a toggle variable is set to 1 and used to prevent the VS rate from being set every gauge cycle.  The following is code compiled into the model:

 

 (M:Event) 'LeftSingle' scmp 0 ==
         (M:Event) 'WheelDown' scmp 0 == or
             if{ (L:DC8_VS_wheel, number) 100 + (>L:DC8_VS_wheel) 1 (>L:DC8_set_vs, bool) }
         (M:Event) 'RightSingle' scmp 0 ==
         (M:Event) 'WheelUp' scmp 0 == or
             if{ (L:DC8_VS_wheel, number) 100 - (>L:DC8_VS_wheel) 1 (>L:DC8_set_vs, bool) }

 

The toggle variable then triggers a single setting of the VS rate as coded in the logic.xml file:

 

(L:DC8_set_vs, bool) 1 ==
    if{ (L:DC8_VS_wheel, number) (>K:AP_VS_VAR_SET_ENGLISH) 0 (>L:DC8_set_vs, bool) }

 

Then there is the code to set the alt hold altitude, also in logic.xml:

 

(L:DC8_VS_wheel, number) 0 ==
(L:Alt_Hold_toggle, bool) 0 == and
if{ 
    1 (>L:knob_click)
    (A:INDICATED ALTITUDE, feet) (>K:AP_ALT_VAR_SET_ENGLISH) 
    1 (>L:Alt_Hold_toggle, bool)
  }
  
(L:DC8_VS_wheel, number) 0 > 
(L:Alt_Hold_toggle, bool) 1 == and
if{ 
     60000 (>K:AP_ALT_VAR_SET_ENGLISH)
     0 (>L:Alt_Hold_toggle, bool)
  }
  
(L:DC8_VS_wheel, number) 0 < 
(L:Alt_Hold_toggle, bool) 1 == and
if{ 0 (>K:AP_ALT_VAR_SET_ENGLISH)
0 (>L:Alt_Hold_toggle, bool)
  }

 

The default FSX autopilot system is tailored for a more modern AP setup and required many modifications to function like a 50 series DC-8 AP. 

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Think I have it. It's a pretty complex system of workarounds.

 

Basically I have the knob set up to do this:

 

 (M:Event) 'LeftSingle' scmp 0 ==
         (M:Event) 'WheelDown' scmp 0 == or
             if{ (L:DC8_VS_wheel, number) 100 + (>L:DC8_VS_wheel) 1 (>L:DC8_set_vs, bool) }
         (M:Event) 'RightSingle' scmp 0 ==
         (M:Event) 'WheelUp' scmp 0 == or
             if{ (L:DC8_VS_wheel, number) 100 - (>L:DC8_VS_wheel) 1 (>L:DC8_set_vs, bool) }

 

And I am letting logic.xml do its thing. Seems to work though it seems like sometimes it gets off sync by +/- 100 fpm possibly from turning the knob too fast. But I think I can live with that.

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