MGL Avionics User Forum

Have three working fuel pressure VDO senders and trying to install another one and not getting voltage reading in the iEFIS Explorer iEFIS light panel - System Diagnostics - RDA1 diagnostics.

In my simulator it has o.3 volts, I measured this 0.3 volts on one of my fuel pressure VDO senders on an aircraft the iEFIS Explorer iEFIS light panel - System Diagnostics - RDA1 diagnostics was also 0.3 volts. In another aircraft I see iEFIS Explorer iEFIS light panel - System Diagnostics - RDA1 diagnostics 4.5 volts.

The instructions for the https://mglavionics.co.za/Docs/MGL%20Av ... %20912.pdf states
Fuel pressure sender input
Use input “Curr1” to connect to a 0-5V or 0.5-4.5V DC output fuel pressure sender. Select the
corresponding sender type in your EFIS fuel pressure configuration menu.
It is also possible to use a resistive pressure sender. In this case connect the pressure sender
to the fuel pressure sender input (the other end of the fuel pressure sender variable resistor is
connected to ground via the engine block).
Also connect a pull-up resistor of 2.7KOhms from the fuel pressure input to the 12V supply
this will energize a typical 200 ohm VDO sender.
Select “Resistive sender” in the setup for a 200 resistance and “pressure increases with
resistance”

So it appears the system does not care what voltage the VDO resistive pressure sender is energized with? 12 volts is ok? I wonder where my other 3 aircraft are getting the 0.3 volts and 5 volts to energize the sender. Any guidance here is appreciated.

VDO senders are resistive senders. This is NOT supported on the RDAC CAN - I think the instructions are clear.

The instructions call for a voltage output sender. This is a sender with built in active electronics that outputs a voltage proportional to pressure. These tend to come in two flavors - 0.5V to 4.5V and 0V to 5V. They are usually powered by a 12V DC source.

Rainer,
I am confused. The MGL instructions for this box as I showed above:
"It is also possible to use a resistive pressure sender. In this case connect the pressure sender
to the fuel pressure sender input (the other end of the fuel pressure sender variable resistor is
connected to ground via the engine block).
Also connect a pull-up resistor of 2.7KOhms from the fuel pressure input to the 12V supply
this will energize a typical 200 ohm VDO sender.
Select “Resistive sender” in the setup for a 200 resistance and “pressure increases with
resistance” "

I have a VDO resister pressure sender on my 3 other aircraft. I am simply asking since I am getting different voltage readings, does it care what the voltage reading is, or can I use the 12 volt as the instructions are clear.