Burkert Type 8175 - Manual (Page 102)

34
8175
ENGLISH
CALIBRATION MENU
0......9
ENTER
0......9
ENTER
ENTER
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
087.3 ft/s within air at 32°F (0°C), if unit=ft or inch
Temperature variation of the velocity:
Default value: 0.59 m/s / °C
0.075 ft/s / °F
If no temperature dependancy of the sound velocity is requested, calculate the sound velo-
city at ambiant temperature with the following equation:
V = 331.4 m/s + 0.59 m/s x T°C
Enter this calculated value and enter 0.00 as the temperature variation coefficient.
GAS COMP 331,4 m/S
322,7 m/S
T° =0.400
T° =0.590
ECHO
Temperature
variation
coefficient