ww w.stratomaster.eu
MGL Avionics
Fuel management FF-2 & FF-4
Install & User’s manual
© 2002-2007 MGL & Delta Omega
www.delta-omega.com
Page 14, june07
Level Sender
If required the FF-2 or FF-4 can interface to a standard automotive fuel level sender(s) as
indicated. Most of these senders are resistive types.
The level input terminal has an internal 1K resistor pull-up to 5V.
Capacitive types can be used provided they have a voltage output not exceeding 2.5V.
Sender’s output range is in general in the 0-0.5V range, and many capacitive senders have an
output which is compatible with a resistive sender.
Senders with an output voltage range above 2.5V need to be connected through a resistive divider
in order to condition the voltage on instrument’s input in the 0-2.5V range.
•
For a 0-5V sender, a resistor divider with 270 Ohm in series and 270 Ohm to ground.
•
For a 0-12V sender, resistor divider with 1.5 KOhm in series and 270 Ohm to ground.
Please note that capacitive senders may exhibit large errors as they are very sensitive to the
composition of the fuel used. We do not recommend using capacitive senders with automotive
fuels for this reason.
Please ensure that the float of the level sender moves freely at all times and that the float is large
enough not to remain submerged in case the mechanism becomes sticky. This will result in an
incorrect indication of fuel level.
Note that you need to perform the calibration routine as outlined in the respective section of
this manual.
Sender pictures
Flow
Level
Power supply
Connect the ground and +12V input terminals to your plane’s power supply (you will need a pre
regulator for a 24/28V supply).
Note for operation on supplies with inductive loads: Any operation of electronic instrumentation on
power supplies that are subject to high voltages caused by operation of inductive loads (starter
motors, solenoids, relays) are required to be fitted with suitable protection.
All Smart Singles are guaranteed to withstand temporary over voltage up to 40V without additional
protection. We recommend that measures are taken to prevent voltage transients in excess of this
limit.
MGL Avionics recommends the fitment of a fuse in line with a 33V TransZorb© to protect electronic
instruments, radios and intercom systems. Only one such arrangement is required for a cluster of
instruments.
Please note that product warranty excludes damages caused by unprotected, unsuitable or
incorrectly wired electrical supplies.
