Starting with SimDash v1.1 the Rev Burner can be used to drive an electronic speedometer. In order to do that, the firmware of the board but be upgraded with the special version available in the Download page. The new firmware must be downloaded and transferred into the board following these simple instructions.
The original firmware is always available from the Download page, in case you decide to use your Rev Burner with a rev counter, as usual.
Only electronic speedometers are supported. Electronic speedometers receive a series of electric pulses whose frequency corresponds to the speed of the car. The number of pulses received for every kilometre or mile is a characteristic of the speedometer, and this value can be fixed or variable. The type of signal generated by the Rev Burner is a square wave at 12V, whose frequency increases with the speed.
The Rev Burner is able to generate up to 67.164 pulses per minute and most of the electronic speedometers work or can be set to work in this range of frequency.
The formal calculation is this: suppose you want to use a speedometer whose top speed is, for example, 200 Km/h. The speedometer must be configured to receive:
67.164 X 60 / 200 = 20.149 pulses per Km, or less, not more.
If the speedometer is configured to more than 20.149 pulses per Km, the Rev Burner wouldn’t be able to generate a signal fast enough to drive the needle all the way up to 200 Km/h.
Anyway most of the aftermarket speedometers can be configured from few to thousand of pulses per kilometre and are fully compatible with the Rev Burner.
Connecting the speedometer
The speedometer connects to the Rev Burner using the the orange 3-ways screw terminal:
- The + and – terminals connect to the power wires of the speedometer. Probably there are more wires to connect to each terminal, if the speedometer has a backlight.
- The S1 terminal carries the speed signal and must be connected to the signal wire (usually green). The signal from the Rev Burner is at 12V.
Configuring the Software
When the speedometer is connected to the board, you can start configuring SimDash, clicking the Config button of the Rev Burner for Speedometers plug-in.
In the configuration form, insert the top speed of the speedometer and whether the scale is in Km/h or Mph.
For each value of speed (expressed in percentage, from 3% to 100%) set the frequency of the signal sent to the speedometer (expressed in PPM, pulses per minute). The frequency can be set moving the slider left or right or using the up and down arrows of the numeric textbox, at the left of the slider. Every time the frequency is changed, a test value is sent to the speedometer.
To give an example, if the top speed is 250 Km/h, the slider of the first row (3%) must be moved until the speedometer displays 7,5 Km/h. Then the slider of the second row (5%) must be moved until the displayed speed is 12.5 Km/h. And so on.
The Import… and Export… buttons are used to load an existing profile or to create a backup of the current settings.
If the number of pulses per minute the speedometer expects for each kilometre or mile is known, it is possible to click the Wizard… button and fill in the correct values. The wizard will then complete the configuration.
