Fuel Senders & Calibration

[nitrousinducedcoma]

We have installed fuel probes in our new wings from a company called Sky Sports.This company has since been sold to Aircraft Spruce in which there technical department does not know much about the senders.The manual for the senders says it is a capacitance system.It has no float or other moving parts and works well with a westach dual gauge (part#WS2DA4).We have tried calibrating the tanks both ways (resistance & capacitance).Nothing happens in capacitance mode but we do get what seems to be a good reading in resistance mode for every two gallons we put in.The problem came when flying.When in level flight the level of fuel would be close to accurate but when you change attitude the level of fuel is all over the place.Basically the fuel level bounces around alot.Is this normal for the system.We just want to know if we did the calibration correct and or if theses senders really will work with the Dynon System.Or do we need to install that convertor that you have.Any help with this problem would be helpful.I also sent a couple of pic's of the sender we use.
Regards
Steve

 

[nitrousinducedcoma]

2nd pic

2nd pic of sender

 

[16FW]

I have those same senders. They are capacitive, but the sender converts the output to resistive to work with the analog gauges. Fuel sloshing may account for the changing level readings.

 

[nitrousinducedcoma]

Thanks 16FW. Dynon said i had to get ahold of the sender manufacture which is Westach to find out what that sender puts out.Westach says the senders i have put out 240ohm to 30ohm and the EMS-D120 needs 0-5 volt out put from the sender.I have to change the senders out of the wing to the 4 wire 0-5 volt.It took some phone calls and some digging but found out what i needed.

 

[dynonsupport]

We can read resistance, and you don't need to change your senders.

We have two modes:
Sensor type 1 is resistance mode
Sensor type 2 is voltage mode.

Normally, capacitive senders output voltage, but yours is unique and outputs resistance. So you should use mode 1 (resistance)

Beyond that, it should work, and as you say, it does. The changing in flight is probably sloshing or something else the sender is telling us to do. We don't do more than show what the sender outputs, so if it's moving around that's the sender changing resistance.

If you do still find issues, you may need to swap out senders to fix the problem, but it's not because of the voltage vs. resistance issues. We've had good luck with the Princeton probes which look a lot like the ones you have.

Sorry if we didn't make the voltage vs. resistance vs. capacitance thing clear enough on the phone.

 

[rockyjs]

I have an aircraft in my shop with the same probes getting a new panel around a FD 180. I'm curious if the calibration on the probe head should be left as is, or recalibrate the probe and then do the calibration for the FD 180 explained in the manual.

 

[16FW]

I would do the probe calibration first. If you don't it might be too far out for the FD 180 to calibrate.

 

[dynonsupport]

If it has a decent voltage or resistance spread already from end to end out of the box there's no need to do anything more. But if moving the arm produces no voltage or resistance change, do its calibration first.