8 posts / 0 new
Last post
Deespeed99
Offline
Last seen: 6 hours 17 min ago
Joined: 02/18/2016 - 13:00
Any way to wire in or use an input for a fuel level sender?

I'm not sure how but know you should be able to use a 0-280ohm (for example) fuel sender to a digital or analog input? Any feedback or advice? I would love to display the fuel level on the CD7 dash instead of having a separate gauge.

Jordan Innovations
Offline
Last seen: 19 hours 46 min ago
Joined: 06/07/2015 - 16:52
You'll want to add the fuel

You'll want to add the fuel level input to whatever is feeding the CD7 - being a CAN dash, it doesn't have analog inputs of it's own (besides the switch inputs).  Once it's on the bus, the CD7 can pick it up and display it however you want.

Jaff
Offline
Last seen: 1 day 4 hours ago
Joined: 01/09/2015 - 03:58
This might help towards the

This might help towards the goal?

I saw it on there site the other day when i was using the designer.

https://gaugeart.com/product/gaugeart-analog-to-can-converter/

Deespeed99
Offline
Last seen: 6 hours 17 min ago
Joined: 02/18/2016 - 13:00
Thanks guys. The fuel sending

Thanks guys. The fuel sending unit isn't canbus based. It's a simple Ohm resistance gauge that reads from 0-180ohm. I was curious how you could tie that into an input with the infinity and use a conversion channel perhaps to display it as a fuel level.

sportbikeryder
Offline
Last seen: 12 hours 50 min ago
Joined: 05/23/2014 - 05:39
Try adding a 90ohm pull up

Try adding a 90ohm pull up resistor. One side of the sending unit to ground, the other to the analog input, AND to a 90ohm resistor. Other leg of resistor connected to the 5v sensor supply. (Would have to check to see how much current the 5v supply can provide)

Should result in output below.
3.33v @ 180ohm
3.125v @ 150 ohm
2.5v @90ohm
2v @ 60ohm
1.25v @ 30ohm
0.74v@ 15 ohm

AEM_SB
Offline
Last seen: 1 hour 53 min ago
Joined: 06/07/2014 - 14:29
I agree with the pullup

I agree with the pullup resistor suggestion from sportbikeryder, but a pullup value of 90 ohms may result in over 0.25W of power dissipated by the fuel level sensor when it is at low resistance. I'm not familiar with how much power fuel level sensors are designed to work with, but this might be near the limits. A higher-ohms pullup resistor would be less ideal in terms of voltage-vs-resistance resolution, but the decreased total current would dissipate less heat in the sensor.

 

If you're not already using the Analog10 pin, ChargeOutTemp is an available input on most 506 and 508 ECUs. There is a table that can be calibrated between 0-100,  and it is broadcast via the standard Infinity CAN datastream.

 

The Infinity has onboard PTC fuses on the 5V and sensor ground lines, they will prevent the current from exceeding ~350mA. You would be well within those limits using a 90-ohms pullup resistor.

Hope that helps,

SB

Jordan Innovations
Offline
Last seen: 19 hours 46 min ago
Joined: 06/07/2015 - 16:52
AEM_SB wrote:

AEM_SB wrote:

I agree with the pullup resistor suggestion from sportbikeryder, but a pullup value of 90 ohms may result in over 0.25W of power dissipated by the fuel level sensor when it is at low resistance. I'm not familiar with how much power fuel level sensors are designed to work with, but this might be near the limits. A higher-ohms pullup resistor would be less ideal in terms of voltage-vs-resistance resolution, but the decreased total current would dissipate less heat in the sensor.

If you're not already using the Analog10 pin, ChargeOutTemp is an available input on most 506 and 508 ECUs. There is a table that can be calibrated between 0-100,  and it is broadcast via the standard Infinity CAN datastream.

The Infinity has onboard PTC fuses on the 5V and sensor ground lines, they will prevent the current from exceeding ~350mA. You would be well within those limits using a 90-ohms pullup resistor.

Hope that helps,

SB

Sure a pullup that low might give you great resolution, but do you really need that on fuel level haha?  I ran my 33-240 ohm reed-switch sensor straight into a temp input (10-bit ADC I believe, 2.49k pullup to 5V) and its limited by the reed switches, not the resolution.  I think there's 12 in there, so it reads about every 8%, works great.

SB's tip on using ChargeOutTemp is fantastic, I was going to have to burn an analog channel to get it over the bus to the dash, but that solves that.  Thanks SB!

FYI, the Infinity lists it as ChargeOutTemp, but the dash lists that same 8-bit unsigned data as TurboOutletTemp_raw.  

sportbikeryder
Offline
Last seen: 12 hours 50 min ago
Joined: 05/23/2014 - 05:39
Just saw you had originally

Just saw you had originally posted 0-280 ohm. My values and resistance suggestion were for 180 ohm, although they should still be legit for the range up to 180.

All good points from the others, probably no need for any sort of real resolution on fuel level, most OEM readouts are very non linear anyway.

For future general reference, when connecting a variable resistance sensor to an analog input, the "pull-up" resistor Is part of a voltage divider circuit. Lots of info available online for voltage dividers, and likely calculators available as well. If the ecu input has an internal pullup, the values an be different based on series / parallel resistors. Always best to calculate numbers and then verify the physical sensor installed rather than rely on the cals. Also, as SB noted, always calculate the power and current levels of the sensor and the supply to be sure you don't exceed working limits.

John