Dynon HDX Fuel Flow "K" Factor settings?

[pacecapt]

I have a Dynon HDX system in my Zenith, I am flying behind a UL Power 350is and I don't have the Red Cubes. I know that the Dynon system will measure FF without the Red Cubes as long as I input a "K" Factor based on my actual GPH. Here is my issue, in the Hardware settings I have required inputs for both the (C37/P14) and (C37/P19) but I don't have any wires attached to the P19. The system will not let me enter all "0's" in P19 and defaults to 10000 as the lowest value. Pin 19 in the EMS also shows nothing attached. Is there a way to delete the P19 in the Hardware setup? I know that P14 is fuel flow to the engine and P19 is return fuel flow back to the tank...

 

[skysailor]

What fuel flow sensor are you using? Did you input the correct type in the EMS settings? If you do not have a return to tank fuel flow sensor you do not need to zero the K factor on the return since it will get no input.

 

[pacecapt]

What fuel flow sensor are you using? Did you input the correct type in the EMS settings? If you do not have a return to tank fuel flow sensor you do not need to zero the K factor on the return since it will get no input.

There are no fuel sensors. The Dynon HDX has the ability to calculate fuel flow based on getting the correct "K" Factor into the settings.

 

[Marc_J._Zeitlin]

There are no fuel sensors. The Dynon HDX has the ability to calculate fuel flow based on getting the correct "K" Factor into the settings.

Yeah, but only if it's getting pulses (even synthetic ones) on pin 14. I have an SDS FI system, and the output from the SDS goes to pin 14. I assume that the 350iS has some sort of FF output from its FADEC system. If you haven't connected that, there's your problem.

 

[pacecapt]

Yeah, but only if it's getting pulses (even synthetic ones) on pin 14. I have an SDS FI system, and the output from the SDS goes to pin 14. I assume that the 350iS has some sort of FF output from its FADEC system. If you haven't connected that, there's your problem.

I know it is connected to the ECU as I do get FF numbers...the basic premise of my question is why does P19 have a required K Factor input (which can't be Zeros) when there is nothing connected to P19. I have to adjust the K factor value to match (as close as possible) to actual fuel usage...

 

[swatson999]

If there's nothing connected to it, then what difference does it make what the K factor is? It'll be multiplying by zero (the input to the pin).

"Nuthin' plus nuthin' is nuthin'. That's mathematics, son. Two half-nuthin's is a whole nuthin'..." - Foghorn Leghorn

 

[Rhino]

"Nuthin' plus nuthin' is nuthin'. That's mathematics, son. Two half-nuthin's is a whole nuthin'..." - Foghorn Leghorn

He was always my hero.

To my knowledge, no, you cannot delete pins in the setup. Just leave it at default.

 

[pacecapt]

If there's nothing connected to it, then what difference does it make what the K factor is? It'll be multiplying by zero (the input to the pin).

"Nuthin' plus nuthin' is nuthin'. That's mathematics, son. Two half-nuthin's is a whole nuthin'..." - Foghorn Leghorn

If you read my comments again you will see that the system will NOT let you have all "0's" in the K factor settings so ""Nuthin' plus nuthin' is nuthin" is not the answer...rather hoping someone from Dynon will respond...

 

[pacecapt]

He was always my hero.

To my knowledge, no, you cannot delete pins in the setup. Just leave it at default.

The problem with "leaving it at default" is that the FF is not accurate...I am working through it, I just thought that someone might have experienced this before and my have some useful suggestions...

 

[Rhino]

Not sure I'm understanding this correctly. If you have nothing connected to that pin, it shouldn't be getting used in your fuel flow calculations. It has a one volt threshold before it is used for calculations. The number should have no effect if nothing is connected to the pin. Position 33 on the serial port correlates to that pin. It might be helpful to export the serial data and see what the 3 bit number is in that position. The range is 0 to 999. Yours should presumably be zero. Other than that possibility, I'd say this is something to approach Dynon with.

 

[Rhino]

The problem with "leaving it at default" is that the FF is not accurate...I am working through it, I just thought that someone might have experienced this before and my have some useful suggestions...

The "plus" was in the quote. The system doesn't add to the number. It multiplies. So nothing (less than one volt) connected to the pin should mean zero, and multiplying that by any number is still zero. That's why he said the setting shouldn't matter.

 

[swatson999]

If you read my comments again you will see that the system will NOT let you have all "0's" in the K factor settings so ""Nuthin' plus nuthin' is nuthin" is not the answer...rather hoping someone from Dynon will respond...

I guess the reference was lost on you. Allow me to paraphrase the cartoon character I quoted:

Nuthin' TIMES nuthin' is nuthin'.

 

[pacecapt]

Not sure I'm understanding this correctly. If you have nothing connected to that pin, it shouldn't be getting used in your fuel flow calculations. It has a one volt threshold before it is used for calculations. The number should have no effect if nothing is connected to the pin. Position 33 on the serial port correlates to that pin. It might be helpful to export the serial data and see what the 3 bit number is in that position. The range is 0 to 999. Yours should presumably be zero. Other than that possibility, I'd say this is something to approach Dynon with.

I agree with your assessment hence my posting in the first place...if I was using Red Cubes, I would need one from the fuel feed to the engine and one on the return line (I fly a UL Power and it has a return fuel line to the tank). If I had Red Cubes then the settings to the engine P14 and the setting from the engine P19 would both be 68000 as the Red Cubes do the calculating (Fuel to the engine P14 minus fuel returned P19 gives you the FF). Since I don't have them I am using the algorithm from the Dynon Software to estimate FF. This is done over time and normally you would adjust PUL/GAL on P14 (higher number is less FF, lower number is more FF). My bottom line is that since I don't have anything on P19 why is it showing on the Dynon Hardware Calibration page and it won't let me input any number less than 10000. I am slowly working through this but I thought one of the experts might have already solved it...

 

[Rhino]

Return flow has always been somewhat of a wonky, hit or miss proposition, and I'm hardly an expert in that regard. And given the highly customized nature of your situation, that's why I recommended you contact Dynon. Whatever resolution you come to, please come back and post it here for future users who may need the information. Good luck.

 

[Dynon]

This reply has 80% confidence, mostly because I don't have access to the engineers that could fully-clarify as of this writing. Things I think are true:

• Fuel flow comes over CAN from the ULPower ECU
• As you've indicated, one doesn't use the fuel flow sensors in this configuration.
• I believe, but am not certain, that the displayed fuel flow equals the CAN-reported fuel flow when the k-factor is set to its default setting.
• Even though there's no fuel flow sensor connected, adjusting the k-factor will ratiometrically adjust the ECU-reported fuel flow. Raising K-factor lowers reported fuel flow . The equations in the install manual would still work as described.
• You can/should unhook the pins as described in the installation manual (see image below). The below was written for the 912 iS, but the same applies to ULPower

 

[Akash408]

Any one please help me

How can we calcualte the k factor of FT 60 fuel flow tranducer.
second question is that
what is the minimum value of k factor of FT 60 and maximums value of k factor

 

[jakej]

Akash - the default K Factor is 68000, as per the Install Manual - afaik there is now minimum/maximum K, it all has to do with each individual installed FF unit & variations of its install. For most GA 4/6 cylinder engines you can probably expect to see the calibrated K factor be in the 50000 - 68000 range, YMMV.
Read the manual - it explains the process

 

[Akash408]

W

process

Which manual i read

 

[Rhino]

https://dynonavionics.com/includes/guides/skyview/SkyView_System_Installation_Guide-Rev_AN.pdf