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FSX Very Basic Question

I tested the gauge in-game. The success was mixed. The Fuel switch worked as expected (though I forgot that the light comes on when the fuel switch is off, so the battery thing works in reverse. Fortunately, I think I can fix that.)

However, the problem was that the APU Starter light would not come on. I'm sure that the code is just screaming the answer at me, but I just don't know enough to catch on. Any ideas? Doug's XML debugger showed that L:APU_Starter was indeed changing to 1, so it must be one of the other values. The debugger did not list L:APU_Ign as an active variable.
Code: 
<Gauge Name="CL6_APU_Panel" Version="0.3">
    <Image Name="APU_Panel.bmp"/>
  
    <Element>
    <Position X="221" Y="52"/>
        <Select>
            <Value>(L:APU_FuelSOV,Bool) (A:ELECTRICAL MASTER BATTERY, bool) and</Value>
            <Case Value="0">
                <Image Name="FuelValveClosed.bmp"/>
            </Case>
            <Case Value="1">
                <Image Name="FuelValveOpen.bmp"/>
            </Case>
        </Select>
    </Element>
  
    <Element>
    <Position X="368" Y="52"/>
        <Select>
            <Value>(L:APU_Starter,Bool) (A:FUEL TANK LEFT MAIN LEVEL,pounds) 5 &gt; and (A:ELECTRICAL MASTER BATTERY,bool) and (L:APU_FuelSOV,Bool)and</Value>
            <Case Value="0">
                <Image Name="APU_Start.bmp"/>
            </Case>
            <Case Value="1">
                <Image Name="APU_Start_Ign.bmp"/>
                1 (>L:APU_Ign,bool)
            </Case>
        </Select>
    </Element>
  
    <Mouse>
        <Area Left="221" Right="285" Top="52" Bottom="116">
            <Tooltip>APU Fuel Valve</Tooltip>
            <Cursor Type="Hand"/>
            <Click>(L:APU_FuelSOV,Bool) ! (&gt;L:APU_FuelSOV,Bool)</Click>
        </Area>
        <Area Left="368" Right="432" Top="52" Bottom="116">
            <Tooltip>APU Start/Stop</Tooltip>
            <Cursor Type="Hand"/>
            <Click>(L:APU_Starter,Bool) ! (&gt;L:APU_Starter,Bool)</Click>
        </Area>
    </Mouse>
  
</Gauge>
 
Check your use of FUEL TANK LEFT MAIN LEVEL. You use pounds unit when it is expecting percent. You might be thinking of FUEL TANK LEFT MAIN QUANTITY.
 
It works when I remove it, though strangely enough it seems to work regardless of the state of L:APU_FuelSOV.
 
TurboCompound said:
It works when I remove it, though strangely enough it seems to work regardless of the state of L:APU_FuelSOV.
Click to expand...
Yeah, that's why I pointed out that it wasn't correct to use (A:FUEL TANK LEFT MAIN LEVEL, pounds), and why I suggested that you remove it from your script so you could see if that was, in fact, the only culprit. Take a look at the online SDK to see a list of all A:Vars and the recommended units. If inappropriate units are used, then variables will return values that likely won't work with your code, as was the case with your example, I believe. The wiki section of this site contains a description of what goes on behind the scenes with units - how Flight Sim handles units.

One other point is that I believe Doug and Tom's debuggers show L:Vars but, if I remember correctly, not A:Vars. That's one reason I use BlackBox3, though its limitation is that it wont work debugging modeldef XML. I think that if you could have seen what was going on with that A:Var, then you would have known there was an issue there. Mind you, each of those tools has its strengths and all are recommended.

Below is a BB3 screenshot of some Fuel A:Vars with various units applied. Its from an airplane with 100% fuel added, 121 gallons in the left main tank. Each value is "correct" in the sense that the values returned follow the FS units logic, but they don't all make sense unless one understands how units work.

Note the value returned for a 99.99% full tank using (A:FUEL TANK LEFT MAIN LEVEL, pounds) is 2.2046. The 5 &gt; in your script was a problem in this case. (A:FUEL TANK LEFT MAIN LEVEL, pounds) is always less than 5, and the Case Value would always be zero. Again, the fundamental error was the incorrect units with that A:Var.

Bob

upload_2015-5-10_19-23-50.jpeg


[edit] Explanation of the BB3 values:

FUEL TANK LEFT MAIN LEVEL: This is a percent type variable, and the default unit of measurement is percent over 100. The tank is ~100% full, so Flight Sim stores the value 1.0000 into memory (1.0000 percent over 100=100%), together with a flag that says its a percent type of unit. When FS is asked to display (A:FUEL TANK LEFT MAIN LEVEL, percent), then it recognizes this as a percent type unit as well, and applies a 100x conversion factor so that the value returned for percent is 99.9987.

However, when FS is asked to display (A:FUEL TANK LEFT MAIN LEVEL, pounds), then it assumes this is a weight variable. The default weight unit is kilograms, so FS assumes that the 1.0000 stored in memory represents 1.0000 kg. When it is asked to covert that to pounds, it returns 2.2046 (1 kg=2.2046 pounds). But that value has no meaning because A:FUEL TANK LEFT MAIN LEVEL is a percent variable, not a weight variable.


FUEL TANK LEFT MAIN QUANTITY: This is a volume variable, and the default unit of measurement is cubic meter. The tank has about 121 gallons in it, so Flight Sim stores the value 0.458038 into memory (121 gallons=0.458038 cubic meters), together with a flag that says its a volume type of unit. When FS is asked to display (A:FUEL TANK LEFT MAIN QUANTITY, gallons), then it recognizes this as a volume type unit, applies the cubic meter to gallons conversion, and it returns 120.9984.

However, when you ask FS to display (A:FUEL TANK LEFT MAIN QUANTITY, pounds), then it assumes this as a weight variable. The default weight unit is kilograms, so FS assumes that the 0.458038 stored in memory represents 0.458038 kg. When it is asked to covert that to pounds, it returns 1.0098 (0.45803 kg=1.0098 pounds). But that value has no meaning because A:FUEL TANK LEFT MAIN QUANTITY is a volume variable, not a weight variable.

Make sense?
 
Last edited:
TurboCompound said:
It works when I remove it, though strangely enough it seems to work regardless of the state of L:APU_FuelSOV.
Click to expand...

Hi,

Besides Bob's comment, you must leave a space between (L:APU_FuelSOV,Bool) and and, otherwise (L:APU_FuelSOV,Bool) is not recognized. Like:

Code: 
<Value>(L:APU_Starter,Bool) (A:FUEL TANK LEFT MAIN LEVEL,percent) 5 &gt; and (A:ELECTRICAL MASTER BATTERY,bool) and (L:APU_FuelSOV,Bool) and</Value>

And you must remove 1 (>L:APU_Ign,bool) in <Case Value="1">. <Case> is a container for other tags, and does not support scripts.

Tom
 
TurboCompound said:
Interesting. I didn't realize that FS processed units that way. I'll see if I can find the right units.
Click to expand...
Keep going! I imagine XML might be easy for you since you already work with SIOC for your home built. That sounds more difficult to me.
 
It's different is all. It's like learning a Slavic language then learning a Germanic language.
That being said, I feel like I'm starting to get a basic idea of XML.

However, there is still the issue of "1 (>L:APU_Ign,bool)." Would I place it here?
<Value>(L:APU_Starter,Bo...and (L:APU_FuelSOV,Bool)and; 1 (>L:APU_Ign,bool)</Value>
 
Code: 
<Gauge Name="CL6_APU_Panel" Version="0.3">
<Image Name="APU_Panel.bmp"/>

<Element>
<Position X="221" Y="52"/>
<Select>
<Value>(L:APU_FuelSOV,Bool) (A:ELECTRICAL MASTER BATTERY, bool) and</Value>
<Case Value="0">
<Image Name="FuelValveClosed.bmp"/>
</Case>
<Case Value="1">
<Image Name="FuelValveOpen.bmp"/>
</Case>
</Select>
</Element>

<Element>
<Position X="368" Y="52"/>
<Select>
<Value>(L:APU_Starter,bool)</Value>
<Case Value="0">
<Image Name="APU_Start.bmp"/>
</Case>
<Case Value="1">
<Image Name="APU_Start_Ign.bmp"/>
</Case>
</Select>
</Element>

<Mouse>
<Area Left="221" Right="285" Top="52" Bottom="116">
<Tooltip>APU Fuel Valve</Tooltip>
<Cursor Type="Hand"/>
<Click>(L:APU_FuelSOV,Bool) ! (&gt;L:APU_FuelSOV,Bool)</Click>
</Area>
<Area Left="368" Right="432" Top="52" Bottom="116">
<Tooltip>APU Start/Stop</Tooltip>
<Cursor Type="Hand"/>
<Click> (A:FUEL TANK LEFT MAIN LEVEL,pounds) 5 &gt; (A:ELECTRICAL MASTER BATTERY,bool) and (L:APU_FuelSOV,Bool) and
if{ (L:APU_Starter,bool) ! (>L:APU_Starter,bool) }</Click>
</Area>
</Mouse>

</Gauge>
 
TurboCompound said:
However, there is still the issue of "1 (>L:APU_Ign,bool)." Would I place it here?
<Value>(L:APU_Starter,Bo...and (L:APU_FuelSOV,Bool)and; 1 (>L:APU_Ign,bool)</Value>
Click to expand...

What I notice after inspecting your code is that you want to show "APU_Start_Ign.bmp" when

Code: 
(L:APU_Starter,Bool) (A:FUEL TANK LEFT MAIN LEVEL,percent) 5 &gt; and (A:ELECTRICAL MASTER BATTERY,bool) and (L:APU_FuelSOV,Bool) and

and, at the same time, you want to keep that status in (L:APU_Ign,bool). It means that (L:APU_Ign,bool) depends on a value returned by the script from above.

Therefore, you can simply code this:

Code: 
<Value>(L:APU_Starter,Bool) (A:FUEL TANK LEFT MAIN LEVEL,percent) 5 &gt; and (A:ELECTRICAL MASTER BATTERY,bool) and (L:APU_FuelSOV,Bool) and d (>L:APU_Ign,bool)</Value>

the d character replicates the result of the previous script, so (L:APU_Ign,bool) can receive a copy of that value.

Tom
 
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