fuel guages

[paulfoster]

have flightdeck 180 installed in RV7A IO 360 setup-had first engine start over weekend.My question relates to the wiring to fuel tanks-have vans fuelguages as backup.when the dynon is powered up the vans guages do not read .i have both wires onto the fuel sender pickup[float]have yet to calibrate the dynon.can both dynon and vans guage share the same pickup?

 

[dynonsupport]

Fuel level pickups cannot share gauges. You must install two senders if you want two gauges. The sender is powered by the gauge, so you now have two things powering the sender. You really want to disconnect this before you power up the plane again, since you don't know what voltage either device is using, so you might damage one gauge with the other.

 

[Steve_G]

Has anybody installed Vans fuel gauges (float-type) as a back-up to the EMS?  If so, how do you install a 2nd sending unit?  

Steve
Vans RV-9A
D-180

 

[philipp_steinbach]

Re: fuel gauges

Installed EMS D-10 in our Xtreme, we use SkySports capacitant fuel level sensors.
After calibration process according to the book all looked well, switch off and on again with the Master still okay, but after 30 min beeing off and switched on again all calibration data were lost.
Any idea? Is the keepalive cable essential for this?

Any chance to get indication for 3 capacitant sensors in the EMS?
We have 2 wingtanks and 1 fuselage tank for aerobatics.

 

[dynonsupport]

That information is stored in memory that does not need power keep it from changing. Do you see the "CAL" label near the fuel tanks indications, or some number that doesn't change correctly or at all?

Only two voltage inputs (for capacitance probes) are supported in the EMS. This is a hard limitation based on the hardware built into the product.

 

[philipp_steinbach]

It shows randomly between 3 and 5 Liters when completely full (65 Liters) and when I check the setup page it asks again for the size of the tank, so it seems to erase everything by the time beeing switched off.
There´s no letters or else near the fuel indicator except "Lit" and the numbers, no CAL.

 

[dynonsupport]

Just to clarify (my post below originally read wrong), fuel calibration data CAN NOT erase itself.

So it sounds like it's not "erasing", but rather, that the calibration that you're ending up with is not valid to begin with.

Whenever you go into the calibration a tank, it always starts completely fresh by asking you how big your tank is, so what you're seeing is expected.

Do you know what voltage your senders output at empty and full respectively? Alternatively, did you happen to write down the numbers the unit displays at the end of your fuel calibration process?

 

[philipp_steinbach]

I had about 40 flights in the last 6 days, so far (except the fuel gauges) everything was ok until yesterday when all 6 CHTs read -99 from startup, even 4 times recycling did not change anything.
Same was for EGTs which showed between 220 and 340 F, quite unlikely... After flying for 40 minutes, suddenly the normal readings reappeared, and with no change to the fuelstate, the fuel indication which read strange values from 0 to 5 no matter how full the tanks are suddenly went to full indication (65 Liters Main, 110 Liters right).

Any ideas?
Could there be a flaw in the EMS itself?

I used a FlightDek 180 for the last 2 years and 250 hrs , this still works perfect, but this device gives me some headache...

The plane will be on display at Sun N Fun, so any advice to make it working nicely is highly welcome!

 

[dynonsupport]

It could be the EMS itself, but also could be something in the wiring.

Particularly, if the 5V excitation line is hooked up or shorted to something it shouldn't be, that can affect readings system-wide.

 

[philipp_steinbach]

The 5V line goes exclusively to the ManP sensor, like described in the Installation Manual.
We ordered 2 more EMS D-10, could you please check and let me know when they are shipped?
We´ll have a government test pilot coming here saturday crosschecking the plane before the CofA is issued.
Would be very helpful to show him a usable fuelsensor...
Thanks for help.

 

[philipp_steinbach]

I found some older thread with obviously similar matters: http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1180359100
In fact, the system asked me also after each step (5 Liters in the Main, 10 Liters in the wingtank) if the fuel was added beacuse the value chagned insignificantly. In fact, for example in the main the empty factor was 48 and still read 7 when it was full and I hit the "full" button.
But the value counted down after each spill, it never stopped.
Also, before calibrating the EMS we calibrated the SkySport sensors with a standard Westach fuel gauge.

 

[dynonsupport]

When the EMS is asking whether or not you are sure you actually put in fuel, it is really gently saying "I'm pretty sure I haven't seen enough of a change to yield a useful reading if you continue".

Now, some float sensors top out before the tanks are actually full (as in the other post), and in this case the EMS is basically telling you that this has happened. Of course, the EMS can only ever tell you about fuel that it can actively measure, so the "full" indication will be what the sender was at when it stopped moving, which will be less than the true capacity of the tank.

 

[philipp_steinbach]

The fuel sensors are described to need 12V, the EMS as far as I understand works with 5V.
Is it better to supply 12 V to the sensors or 5V?

 

[josok]

From your question i suppose 12 V is the input voltage, on what the sensor works. The output of your sensor(s) is up to 5 volts, depending on how much fuel it sees. That's what the EMS takes as input. In short: feed 12V sensors with 12 V. I would measure that "up to 5V" output of your sensor, to see if it makes sense. Is there maybe a calibration procedure for your sensors? If there is, that has to be done before calibrating the EMS.

Edited: In another post you write you have Westfach senders. Make up your mind please?

Regards,

Jos Okhuijsen

 

[philipp_steinbach]

The SkySports sensors are produced by Westach, so we´re talking about the same topic anyway.
There is a calibration procedure which we performed before with a "steam gauge".

To shorten this discussion in general:
Are there any fuel sensors that you recommend?
No matter which principle, all I want is to know how much fuel is in the tanks...
I would be happy to get a link or a name of something tried and trusted!

 

[dynonsupport]

Anything that outputs a resistance between between 20 and 240 ohms will work. For RVs, the Vans sensors work fine. Stewart Warner floats work, as would many of the other automotive ones. Basically, anything that is functionally a variable resistor. Since we calibrate the actual fuel sender in your plane, it doesn't have to go exactly from 20 to 240 in your tank, and if it happens to go to 300 ohms, it would still work.

Additionally, active sensors will work if they output a voltage between 0-5V DC. The probes that Princeton Electronics sells through Aircraft Spruce work well. For RVs, the capacitance plates available on some models will work with additional capacitance to voltage converters that we sell for $50 a tank.

And for all the engineers out there - note that if the voltage on these inputs goes much above 5V, it will mess up all the readings in the EMS. If your sender outputs 0-12V, you could use a resistor divider to get it down to 0-5V, but remember that if the voltage output varies with the battery voltage, the fuel the EMS reads will vary too, which is a bad thing.

 

[josok]

Hi Philipp.
Princeton capacitive, with 5 level points is the one i am using. Seems to be pretty precise in combination with the D180.

Some cheking on the Westach senders, they make capacitive senders, 0 to 5 volts output, should work fine. They make also capacitve variable resistance probes, and the spec seems to be within the range Dynon accepts. And they make a float type sensor, 30 to 240 ohm, which no further spec. It could be a 3 wire beast. So check and confirm the type number you have.

Regards,

Jos Okhuijsen

 

[dhallpolo]

capacitive fuel sender wiring

I'm installing the Dynon capacitive fuel probes.

I plan to supply the 12V feed to each probe from the E-Bus. Any guidance on size of fuse to protect both probe lines?

I like the mini-ATC inline fuses, where smallest size is 2A....

Don

 

[dynonsupport]

The capacitance to voltage converters draw basically no current, so you can use a very small fuse - 1A or 2A would be fine. Remember that fuses protect wires, not the devices themselves, so make sure you select a wire gauge that is appropriate for the fuse you select and the wire length you run (it needs to be able to handle up to that amount of current without burning up).