Dynon Avionics SkyView System Installation Guide - Manual (Page 161)

SV-EMS-220/221 Installation and Configuration
SkyView System Installation Guide – Revision S 7-49
Fuel Level Sensor
Dynon Avionics does not sell fuel level sensors.
The SV-EMS-220/221 supports both resistive type sensors as well as capacitive sensors which
output a voltage (e.g., Princeton). If you have a capacitive sensor which does not output a
voltage on its own, you may be able to use Dynon’s Capacitance-to-Voltage Converter. Read the
relevant section below for the type that you are installing.
After installation, fuel level sensors must be calibrated. Your SkyView display
utilizes onscreen wizards that help you do this. Go to the EMS Calibration Menu to
access these wizards (SETUP MENU > HARDWARE CALIBRATION > EMS
CALIBRATION).
Once a capacitive fuel level sensing system is calibrated for a certain type fuel, only
that fuel should be used and the aircraft should be placarded for such. For example,
ethanol has a dielectric constant much different than 100LL or Auto Fuel. If
calibrated for 100LL, then by using Auto 10% Ethanol in the tanks the indications
could off by 50%.
It is important to understand that fuel level measurements are subject to the
physical limitations of the sensor. Depending on your fuel tank and sensor
geometry, there may be some immeasurable fuel at one or both ends of the fuel
level sensors’ range. SkyView’s fuel calibration process is designed with this in
mind, and always takes the conservative approach to ensure that it does not report
erroneous fuel readings that might indicate that there is more fuel on board than
there actually is. The end result is that you may experience fuel readings at “full”
that are numerically less than the physical capacity of the tanks, and in this case
you may also see no apparent change in fuel level readings when the sensor is
maxed out on the full side. Similarly, on the empty side, you may see a zero
quantity indication before the tank is truly empty if the sensor has reached the
bottom of its travel or measuring capability when the tank still in fact has fuel in it.
Resistive fuel level sensor
You may connect as many resistive fuel level sensors to the SV-EMS-220/221 as open general
purpose inputs will allow. We recommend that pins 20 and 21 of the SV-EMS-220/221 D37 are
used before other general purpose inputs.
Capacitive fuel level sensor
Capacitive fuel level sensors are only supported on pins 8, 22, 23, and 31 on the SV-EMS-
220/221 D37. Capacitive sensors must output a variable voltage within the ranges of 0-5 volts
DC.