Help with custom sensor definition

JTD

Member
Joined
Oct 26, 2008
Messages
122
Location
dallas tx
Is there any one out there that can help me create sensor definition for two pressure transducers. And show me how to add to file.
 

kurtfly

I love flying!
Joined
Jun 21, 2014
Messages
211
Tim,
It has been a while since I have added my pressure sensor but this is what I remember:

Export your current USER files to usb stick and put them on your computer  The .SFG file is the sensor definition file.  Open this file with Windows notepad or any text editor.

I added a hydraulic pressure sender to my system.  It has an output of approx 500psi/volt with an output range of approx. .5 to 4.5V (0 to 2000psi).  So, paste this to the bottom of your sensor .SFG file.

sensor={
id=UMA HYDRAULIC PRESSURE
;UN-VERIFIED
function=PRESSURE
pins=C37_P8 C37_P22 C37_P23 C37_P31
name=HYD PR
min_val=0
max_val=2500
resolution=0
round=10
is_piecewise=0
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=502
c_x0=-265
}
low_resistance=NONE
low2high_cross=0
high_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=0
c_x0=0
}
high_resistance=NONE
high2low_cross=0
window=.2
shift=3
age=16
}


Adjust the C_x0 and C_x1values to match your transducer.  The industry standard y=C1*X + C0.  If you tell me your sensor output I can help with the calibration.

Add one more sensor definition for the second transducer. Change the name=HYD PRESS to whatever you want to name it.

Save this file as any "unique name".SFG and put it on a usb mem stick.  Import the new .SFG file to your Skyview system.  Then configure the new sensor as any other.  chose the widget, size and location, etc.

This should work - the only thing you need to be aware of is when updating SV firmware you will have to re-import your custom SFG file after upgrade.
 

JTD

Member
Joined
Oct 26, 2008
Messages
122
Location
dallas tx
Kurt
One of the things that confuses me is the Pins=. I want to connect my pressure sensors to pin 20 and 21 respectively. In you example you have them P8, P22,P23, P31. I just don’t understand. When I look at my SFG file I see this as well.
Thanks
Tim
 

kurtfly

I love flying!
Joined
Jun 21, 2014
Messages
211
The pins you use depends on the type of transducer you are using and the output it provides.  My UMA pressure transducer outputs a voltage.  It is powered by the aircraft power buss, not SV.  The best choice for me was the "Type C" input. 
You should be able to use the Type A for most pressure transducers that output 0 to 5 V.  Just copy (2 times) a section from your .SFG file that is for the pins you are using.  You will have to change the fields: id=new transducer, name=PRES1 or PRES2, Min_val and Max_val, and calibration Coefficients.

sensor={
id=KAVLICO 150PSI FLUID PRESS (101693-000)
;VERIFIED
function=PRESSURE
pins=C37_P4 C37_P6 C37_P7 C37_P8 C37_P9 C37_P10 C37_P11 C37_P12 C37_P20 C37_P21 C37_P22 C37_P23 C37_P31
name=OIL
min_val=0
max_val=150
resolution=0
round=1
is_piecewise=0
low_coeff={
c_x4=0
c_x3=0.0956743059068595
c_x2=-0.619407933883778
c_x1=38.9340680988917
c_x0=-20.8757934103442
}
low_resistance=PULL_UP_10K
low2high_cross=0
high_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=0
c_x0=0
}
high_resistance=NONE
high2low_cross=0
 
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