GSSI SIR 4000, Manual

Page: 38 / 163

Geophysical Survey Systems, Inc. SIR® 4000
Manual
MN72-433 Rev F 32
Calibrate SW
Calibrate the survey wheel when you change wheels or the ground
surface changes. Begin by selecting a Survey Wheel Mode, either
Quadrature or Pulse, and then follow the instructions.
Quadrature Mode
is intended for dual channel encoders and will track rotations and the
direction the encoder turns. This means that data are collected in forward
and reverse directions.
Pulse Mode is intended for single channel
encoders and tracks encoder rotations, not the direction. This mode is
useful for field delineation; pulling the wheel backwards will not collect
data, but a cursor will move backwards across the screen. The cursor
will help determine where a particular target is located along your
transect. After calibration select Apply to save the New Calibration
Value or cancel to exit the Calibrate SW menu without saving.
1
Select calibration distance – The default distance is 10 meters or feet but this distance can be
changed. The longer the calibration distance the more accurate the calibration should be.
2
Position Antenna on the Start mark – The antenna or system can be positioned anywhere at the start
as long as you use the same point on the antenna or system when you stop.
3
Press the Start button – This is the green Start button located on the keypad of the SIR 4000.
4
Move antenna to the stop mark – This should match the same location on the antenna or system
where you started.
5
Press the Stop button – This is the red Stop button located on the keypad of the SIR 4000.
6
Select Apply to save the current calibration setting.
Note
: The SIR4000 saves the survey wheel encoder calibration value in counts/ meter no
matter your selected units of measure. That means that if you are used to working in English
(Imperial) units and are familiar with a Model 620 tow-behind wheel calibration value of
~127/ft, the new calibration value you will see will be ~417.