Pro-Form XT 70 User Manual download pdf (Page 50)

GPX Pro Manual45

1.8.3.6 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.

Since the accelerometers are highly sensitive, it is important that for accurate readings, the GPX

be mounted FIRMLY on a SOLID part of the vehicle.

Do not mount the GPX to a surface that is subject to excessive

vibration or movement.

1.8.3.7 Wheel Speed

The GPX can acquire wheel speed data on either channel 1 (digital/analog) or channel 5 (digital

only).

In order to acquire wheel speed, the wheel needs to have a hall-effect (magnetic) or similar

pickup which determines the rotational speed of the wheel. (Another example might be an

infrared or laser source which gets "interrupted" by a disc with holes that is mounted to the

wheel.)

(A simple example is the bicycle computer. It consists of a magnet attached to a spoke of the

wheel, and a "pickup" which detects the magnet passing by.)

To increase accuracy, the more "pickup spots" you can utilize on the wheel, the better. The

1 2 ... 45 46 47 48 49 50 51 52 53 54 55 ... 100 101

No comments

Pro-Form XT 70 User Manual Page 50