How do I connect my Fuel Sender.
Connecting a fuel sensor to the DASH2 (or one of our data loggers) is the same as connecting any other type of analogue sensor. The first thing to do is to connect the fuel sender to one of the analogue inputs. Fuel senders come in a number of different styles and can have 1, 2 or 3 wires coming from them. In the case that the fuel pump is actually in the fuel tank there might also be another 1 or 2 connections to this (making a total of up to 5 connections on the fuel tank), but these are obviously not relevant and should be just ignored.
Instructions on how to connect to a 1, 2 or 3 wire sensor are included here.
Note that you can run the fuel sensor off either the 12v from the main car battery, the 5v reference output from the DASH2 or data logger, or an external reference supply.
- If you run the sensor from the 12v car battery you should be aware that the sensed fuel level voltage will change slightly depending on how “charged up” the battery is, if high accuracy is required then this maybe a consideration
- If you run the sensor from the 5v reference then ensure that the maximum current for the reference output is not exceeded. For the DASH2 this is a total maximum load of 50mA
Once you have got a voltage signal from the fuel sender, then the next step is convert the voltage into a more useful fuel level – typically this is calibrated as either litres, gallons or a percentage. Alternatively, if you make an estimate of the vehicle’s average fuel consumption, then it could be calibrated as the range left.
Information about how to convert a voltage to a measured value is included here: http://www.race-technology.com/wiki/index.php/HowDoI/ConnectMyOwnSensor
So in the specific example of the fuel level sensor, you start with a minimum amount of fuel (which will indicate as empty) and measure the voltage, and enter “0” for the fuel level. Then add a known amount of fuel, for example 5 litres and measure the voltage, and enter these results into the table. Repeat this procedure adding more and more fuel and each time measuring the voltage until the tank is “full”.
Once this is done is might be worth checking you results by doing the same thing (adding more and more fuel) and reading the results from the display.
A few notes that might help in doing this:
- You can use the lite monitor software to measure the voltage going into the DASH2 or DL1 on the PC, there is no need to use a volt meter.
- Since this procedure is quite labour intensive, please keep a record of the results written down somewhere!