Redundant fuel gauges

[Thoug(Guest)]

Hello,

I'm planning on a EFIS D100/EMSD100 installation in my RV-9A. Prior to this plan I was going to use Van's basic engine gauges, so I had already purchased the fuel gauges. I would still like to install these for redundancy. My question is, can the EMS and these fuel gauges share the standard resistive type fuel level sensors?

I'm an electrical engineer, so I understand that the gauge/EMS need to apply a voltage to the sensor resistor in order to measure the resistance; and having both the gauge and EMS trying to do this would likely confuse both instruments. Can the EMS be programmed for capacitive sensors (where it's measuring a voltage) and measure the voltage induced by the fuel gauge?

Thanks,
Todd Houg

 

[dynonsupport]

Todd,
Your plan will work. We have internal pull-up resistors, but these are turned off in capacitive mode. Just hook the signal wire from the gauges to the input pin on the EMS, configure for cap mode, and you should be fine. We calibrate all fuel sender types the same, so you would just do the normal calibration routine.

We expect a 0-5V input range on this pin, so if the gauges are pulled up to 12V, you might need a resistor divider to fit this input into our range. It doesn't need to do the full 0-5V range though- our cal procedure will take care of that.

 

[Thoug(Guest)]

Excellent, I was hoping that would be the case. I meant to ask what the voltage ranges you were expecting, you're one step ahead of me! I haven't tested Vans gauges yet, but I'll hook them up and see what voltage ranges I get. I'll make sure they stay in the 0-5V range.

Thanks again,
Todd Houg