MobiFlight Community Support

Hello all,

I have been messing around with my Stepper (28BYJ-48) together with the ULN2003. I am rebuilding an old King air B200 simulator and have started with the engine gauges. Now, I am working with the ITT gauge. (http://prntscr.com/ehfwxi) this one in particular.

I am using the following settings:

Offset = 0x2038
Float
Byte = 8
No interpolation
Sim = 1200 (reason for this is 1200 degrees max on the gauge)
Stepper = 1700 (full 2048 not needed as it's not 360 degrees round).

After using this and setting my zero point, it works well and it shows the ignition of the engine nicely, however it's not on the correct position though. After engine start, the needle should be stable just before 6 (600 degrees shown on picture), however it's on 9 (900 degrees) which is way too high, but when I shut down it does go all the way back past the 2.

My question is, should I be using interpolation if so how exactly or should I change my sim / stepper settings (was playing around with these earlier, however can't find the best settings for it). I am using the Carenado B200 King air.

Thank you

Hi

As shown in the picture youre gauge is not linear... Not test it but i think the supported offsetvalue is linear normaly.

For those situations you got 2 ways.....

1. You design the backlabel of youre gauge yourself with a linear logic ( The angle between 2 full numbers is same all over the display. then you can work with Raw Offsetvalue.

2. You use the Original NON Linear Gauge Label.... then you need interpolation.... You need to calculate every Step 0-1 ; 1-2 , 2-3 and so on and need to know the angle between 2 Numbers....
You can do this by testing, or you can use math calculation and angle messerusation to find out the right interpolation system.

Hello,

I have now used the interpolation setting and for now have set three values: zero, idle and full power. This "mimics" the ITT value quite well but will add more to make it more accurate, thanks for the help so far!

Thanks

Nice to hear this work for you now.....

Just another hint .....

First.... Do you realy need to reduce the Stepper value ( Using not a 360^ circle ) ?? I see in 3 o clock position there is the "2" Point.... Shortly right of 12 o clock position is the "full 12" point. where is the needle when Aircraft is OFF in the Virtual gauge or in real plane ??
Does it turn below the 2 ( Somewhere between 12 and 2 Position ?? )
If yes then this additional turning range must be implied in youre Stepper Range, too.... Else the lowest point is "2" and it shows 2 already if valie is 0 !

And a hint to find easy the positions......
If you not like to do math calculating you simply can use the "test" button for all points....

After define the Circle range correct and define the Sim Value range you can work with "test" function.
In youre example it was 1200 / 1700
Use Test with a test value from example "100" and see where the needle is stops.... If its not on a Full number increase or decrease the test value... maby to 90 or 110. You will get a feeling after some trys.
If you find a value that exactly hits the needle to a full number then write down this on a piece of Paper.
Do this for all Numbers on youre gauge.... And then you can enter this in youre Interpolation.

Hello!

Thank you for the extra information, much appreciated! I will try this today or tomorrow when i'm next working on the Sim and let you know of my results!

Thanks