Analog fuel level sensors

In certain situations it is not possible to extract the fuel level from the vehicle with the ECU and it is also not possible to pierce the tank to use the Technoton. In this case we can use the analog expander to read the resistive sensor that the vehicle brings. Normally this sensor delivers values between 0 and 5 volts, although with the analog expander we can read up to 28 volts.

1.- Characterize the analog fuel sensor:

We measure the voltage that it delivers to us at 0% capacity.
We measure the voltage that it delivers to us at 50% capacity.
We measure the voltage that it delivers to us at 100% capacity.

It is important to convert volts to thousandths of a volt. We must capture each of these measurements for each tank that we want to monitor (Up to 4 tanks using the analog expander).

We are not limited to 3 relationships, we can capture more data for greater precision in measurements.  Finally, we need to write down the tank tasting capacity in liters.

2.- Structure the information collected.

units_abbrev – Abbreviation of measurement units (l = liters in this case)
name – Name of the sensor that will appear in the tracking indicator.
tank_volume – Total tank capacity in liters
tank – Ratio between tank percentage and thousandths of a volt corresponding to that percentage
source – Pegasus field where the analog data comes from.

Figure 1.- Left, minimal data. Right, higher data resolution.

3.- Upload the information to the vehicle using the API</p>
Using a tool like postman we will do the following PUT to this URL https://YourPegasusUrl.com/api/vehicles/YourVehicleID

Where YourPegasusUrl.com is the url of your site and YourVehicleID is the vehicle identification number.

This is the complete payload:

{
“properties”: {
“$analog”: [
{
“units_abbrev”: “l”,
“name”: “Filtered Fuel Sensor 1”,
“tank_volume”: 303,
“type”: “float”,
“filter”: {
“type”: “polynomial”,
“tank”: {
“0”: 2500,
“50”: 3350,
“100”: 4200
}
},
“source”: “an_fdiff_in1_in2”,
“sensor_type”: “fuel”,
“units”: “liters”,
“decimals”: 1
},
{
“units_abbrev”: “l”,
“name”: “Filtered Fuel Sensor 2”,
“tank_volume”: 303,
“type”: “float”,
“filter”: {
“type”: “polynomial”,
“tank”: {
“0”: 2500,
“50”: 3350,
“100”: 4200
}
},
“source”: “an_fdiff_in3_in4”,
“sensor_type”: “fuel”,
“units”: “liters”,
“decimals”: 1
},
{
“units_abbrev”: “l”,
“name”: “Filtered Fuel Sensor 3”,
“tank_volume”: 303,
“type”: “float”,
“filter”: {
“type”: “polynomial”,
“tank”: {
“0”: 2500,
“50”: 3350,
“100”: 4200
}
},
“source”: “an_fdiff_in5_in6”,
“sensor_type”: “fuel”,
“units”: “liters”,
“decimals”: 1
},
{
“units_abbrev”: “l”,
“name”: “Filtered Fuel Sensor 4”,
“tank_volume”: 303,
“type”: “float”,
“filter”: {
“type”: “polynomial”,
“tank”: {
“0”: 2500,
“50”: 3350,
“100”: 4200
}
},
“source”: “an_fdiff_in7_in8”,
“sensor_type”: “fuel”,
“units”: “liters”,
“decimals”: 1
}
]
}
}

Figure 2.- Using Postman to send data

4.- Done!!

It only takes Syrus to start reporting analog data for Pegasus to do the rest of the work.

Notes:

1. The Syrus must have the analog expander enabled.
2. In this example, each sensor uses 2 analog cables from the analog expander
3. It is necessary to add the extended AW TAG for the values to be reported to Pegasus.
4. In most cases, the vehicle’s analog sensor no longer receives voltage when the ignition is turned off. The sensor shows 0v -> 0% fuel. To prevent these fuel “leaks” from being displayed, the Syrus must be configured to only report analog values when the ignition is ON.

• This topic was modified 3 years, 6 months ago by Eugenio Balam. Reason: Format correction
• This topic was modified 3 years, 6 months ago by Eugenio Balam. Reason: Format correction
• This topic was modified 3 years, 6 months ago by Eugenio Balam. Reason: Note 4 added