Sokkia CX-62 Operator's Manual page 266

• Atmospheric correction factor is calculated and set using the entered values of
the temperature and air pressure. Atmospheric correction factor can also be
entered directly.
Items set, options, and input range (*: Factory setting)
Mode (Distance measurement
Mode)
Reflector
PC (Prism constant)
Temp. (Temperature)
Air pressure
ppm (Atmospheric correction
factor)

Atmospheric correction factor
The velocity of the light beam used for measurement varies according
atmospheric conditions such as temperature and air pressure. Set the
atmospheric correction factor when you wish to take this influence into
account when measuring.
• The CX is designed so that the correction factor is 0 ppm at an air pressure
of 1013 hPa, a temperature of 15°C, and a humidity of 50%.
• By inputting the temperature and air pressure values, the atmospheric
correction value is calculated using the following formula and set into the
memory. (humidity is regarded as 50%)
Atmospheric Correction Factor (ppm) =
t : Air temperature (°C)
p : Pressure (hPa)
e : Water vapor pressure (hPa)
h : Relative humidity (%)
E : Saturated water vapor pressure
• e (water vapor pressure) can be calculated using the following formula.
With constant pressure, a temperature change of 1°C: an index change of
1 ppm.
Fine "r"*, Fine AVG (Setting: 1 to 9 times),
Fine "s", Rapid "r", Rapid "s", Tracking
Prism*, Sheet, N-prism (reflectorless)
-99 to 99 mm ("Prism" is selected: 0*,
"Sheet" is selected: 0*)
-35 to 60°C (15*)
500 to 1400hPa (1013*)/
375 to 1050mmHg (760*)
-499 to 499 (0*)
0.294362
282.324 – ------------------------------------------
1 + 0.003661
258
33. CHANGING THE SETTINGS
×
p 0.04127
+ ------------------------------------------
×
t 1 + 0.003661
×
e
×
t