PAVAS Calibrate Speed at 60 kph

This menu is used to calibrate the speed at 60 kph. It is included for completeness since other menus perform the same function and are easier to use and provide greater accuracy.

The calibration procedure is to drive to 60 kph and press the Select button. PAVAS measures the time between wheel distance pulses and then applies a factor to scale the speed reading to 60 kph. The scaling factor is saved immediately. This is the data used for Comparison readings.

The menu displays the number of wheel pulses and the calculated speed using the current calibration factor. When the Select button is pressed, the calibration factor is updated. If wheel pulses are not detected, an error message is displayed. If the Select button is pressed without any wheel pulses, the menu item is aborted with a message.

There are a number of difficulties in using this process. The first is having the vehicle drive at exactly 60 Kph. Since PAVAS is accurate to 0.1 Kph or better this is difficult. The second is that a speed reference has to used to determine if the speed is 60 Kph. This is usually a GPS unit which typically, only displays the speed to +/- 1 kph. The GPS speed is only accurate if the vehicle is traveling in a straight line on a level service. To perform this measurement accurately, a second person is required.