Manual speed calibration factor calculation

Configure the Speed Sensor Factor (SSF) in millimeters for accurate speed and distance calculations. Complete a manual or automatic calibration with magnet numbers and vehicle specifications.

Note:

Topcon recommends that you still complete an automatic speed calibration.

It is necessary to configure the instrument with the correct Speed Sensor Factor (SSF) to show the correct speed and correctly accumulate distance. This is the distance traveled between pulses received from the sensor. If the calibration factor is known, then you can enter it directly.

It is necessary to calculate all factors in meters. If you calculate the factor with any other unit of measurement (for example, feet or centimeters), the forward speed display will be incorrect.

Notice:

Although you calculate the metric factor is in meters, you must multiply by 1000 and enter the factor in millimeters.

Select Operator menuSpeed Cal
Try to get a factor that is less than 2.000 m.
ADDITIONAL INFORMATION:
The smaller the speed sensor factor, the better the speed update.
Calculate the applicable factor(s) in meters:
ADDITIONAL INFORMATION:
- If a single magnet is installed, you must find the distance traveled for each turn of the propeller shaft. To find this distance, drive the vehicle forward for exactly 10 turns of the propeller shaft. Measure this distance (in meters) and divide by 10.
- If two magnets are installed, the distance is one half the effective rolling circumference of the wheel. To find this circumference, drive the vehicle forward in field conditions (with the implement attached if applicable), for exactly 10 turns of the sensed wheel. Measure this distance (in meters) and divide by 20.
- If 4 wheel magnets are installed, the distance is 1/4 the effective rolling circumference of the wheel. To find this circumference, drive the vehicle forward in field conditions (with the implement attached if applicable), for exactly 10 turns of the sensed wheel. Measure this distance (in meters) and divide by 40.
If the calibration factor is greater than 2.000 m, it can be necessary to install extra magnets. Topcon recommends extra magnets if the vehicle has large diameter wheels or moves slowly. In extreme circumstances, the speed continually goes to zero as it times out before the next pulse arrives.
If a GPS Satspeed sensor is installed, the Speed Sensor Factor is 7.8 mm/pulse.
Figure: Manual speed calibration factor calculation