Global Water FP111 User Manual page 13

Global Water
800-876-1172 • globalw.com
Set Calibration Factor
From the Set Calibration menu screen,
press Set to change the calibration factor.
The calibration factor is factory set and will
generally not need to be changed. If you
wish to change it, press SET. Use the UP
and DOWN arrow buttons to select a new
calibration factor. Press SET to save the new
selection and return to the menu screen. Press
BACK to return to the menu screen without saving.
In the menu screen, the calibration number shown indicates the
current stored setting.
The calibration factor is equal to the rotation speed of the propeller in
revolutions per minute that is equivalent to 1 foot per second of water
velocity. It is used to scale the rotation of the propeller to the water
velocity in FT/S. In the example shown, 323 RPM = 1 FT/S. The
calibration factor must be set in the range of 200-400.
The calibration factor scales rotational speed to velocity in FT/S only.
If the flow units are set to M/S (meters per second), the calibration
factor does not need to be changed. Conversion between FT/S and
M/S is done mathematically by the flow computer.
The flow probe computer is factory calibrated to each flow probe at
the time of purchase and should not need to be changed. The
calibration factor is supplied on the calibration certificate that comes
with each flow probe. Should this scaling factor be accidentally
changed, consult this calibration certificate for the flow probe or
contact Global Water and provide the serial number of the flow probe.
Because each flow probe varies slightly, the calibration factor may be
different for each one. If a replacement computer is purchased, or
the computer is to be used on a different flow probe, the calibration
factor may need to be changed in order to gain the most accuracy.
The scaling factor is used to calibrate out the differences between
flow probes only, there is no variation from one computer to another.
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