Jamar RAC Geo II, User Manual

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RAC Geo II User’s Manual
4-6
Automatic Calibration Procedure
In order to accurately measure distance, your RAC must know the exact
distance that the vehicle will travel based on pulses from the vehicle's speed
sensor. The calibration number is the automatic calculation that represents
the number of pulses received over a set distance. This number, once cal-
culated, will remain accurate until a change to
the vehicle occurs, such as different size tires are
put on the vehicle, tire wear, tire pressure change,
etc. Such changes will require a re-calibration in
order to maintain proper accuracy.
The RAC Geo has the ability to store four (4)
separate vehicle calibration numbers in memory. This simplifies sharing
one instrument between up to four different vehicles.
In order to calculate the calibration number for your particular vehicle, you
must first establish a
calibration course . The length of the course can be
any known distance more than 500 feet. One thousand feet is ideal, but the
course can be any distance over 500 feet (for example, 623 feet from pole
to tree). Your course should be
straight
and
accurate
, so take the time to
measure the course using a 100' tape or hand wheel. Mark the beginning
and ending points so they can be seen from inside your vehicle. Remember,
the course length can be any
accurate
distance over 500 feet, so for conve-
nience you could use a telephone pole or other marker as reference point.
Note: If you are using the Metric unit of measuring, laying out the
calibration course in feet is required to obtain the most accurate cali-
bration number.
Step 1
Slide the ON/OFF switch to ON. Your
RAC will perform a brief Self Test.
The current calibration number will be
shown in the larger, upper display (D-1)
and CF U(vehicle 1, 2, 3 or 4) in
Calibration is only
needed if you are
using an external
distance sensor
Fig. 4.4
Calibration Display on Start-up
Note that calibration is only required if you are using an external sensor,
such as a modular or magnetic sensor. If you are using the built-in GPS re-
ceiver to do distance measuring you
DO NOT
need to calibrate the Geo.