Gas Characteristics - Burkert 8175 Manuel Utilisateur

4.4.4 Gas Characteristics

In order for the 8175 level transmitter to find a precise measure of the level, the characteri-
stics of gas between the liquid and transmitter have to be defined.
If this value is not known either a default value can be applied or the characteristics can
-
be calculated by performing a 2 point Teach-In.
Within this option the values must be entered in m/s or ft/s depending on the type of
-
units selected (metric or imperial).
The default values for the gas characteristics are as follows:
Velocity of sound within the gas:
It is important that the velocity entered within this option is for the gas at
a temperature of 0°C.
Default value (air): 331.4 m/s within air at 0°C (32°F), if unit=cm or m
Temperature variation of the velocity:
Default value:
GAS COMP
ECHO
If no temperature dependancy of the sound velocity is requested, calculate the sound velo-
city at ambiant temperature with the following equation:
Enter this calculated value and enter 0.00 as the temperature variation coefficient.
CALIBRATION MENU
087.3 ft/s within air at 32°F (0°C), if unit=ft or inch
0.59 m/s / °C
0.075 ft/s / °F
331,4 m/S
ENTER
0......9
322,7 m/S
V = 331.4 m/s + 0.59 m/s x T°C
34
T° =0.590
ENTER
0......9
T° =0.400
ENTER
Temperature
variation
coefficient
8175