XT Racing GPX Pro - Acceleration

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GPX Pro Manual40

NOTE: When you are going below about 3mph (5kph), the gear

will be reported as "N" when utilizing rpm/speed ratio to report

gear.

There is one particular advantage to using the rpm/speed ratio for capturing gears (even if you

have a gear sensor), if you are already capturing RPM: using this method does not "use up" an

analog input.

1.7.3.5 Acceleration

Your GPX is equipped with a sensitive 3-axis accelerometer. This, combined with GPS data, allows

data acquisition of G forces involved with acceleration/braking ("longitudinal" acceleration/

deceleration), and turning ("lateral" Gs). It is also used for accurate determination of the start of

some types of Point-to-point and Drag races.

In GPStudio, longitudinal Gs are as follows: >= 0G (positive numbers) = acceleration; < 0G

(negative numbers) = deceleration. For lateral Gs, negative numbers = turning to the left;

positive number = turning to the right.

Since the GPX may be mounted in any orientation, the accelerometers require calibration.

Calibration requires that the GPX be mounted securely on the vehicle, and then the vehicle be

started and stopped in as straight a line as possible (i.e., accelerated from a complete stop to a

speed, and then decelerated back to 0). The more you accelerate and decelerate during the

calibration, the better, but keeping as straight a line as possible is even more important. The

calibration will only be as accurate as this “trial run”.

You must reach a top speed of at least 7 mph for the calibration to

be successful.

NOTE: any re-positioning of the GPX on the vehicle (even in a

slightly different orientation) requires accelerometer re-

calibration.