Xylem Expert 800-900 - Manual (Page 20)

Manual
GB Manual Expert Log 800-900.doc
20
Offset:
- Offset is a freely selectable value (positive or negative) which is added to the length
calculated. The default value is 0. For example, by giving a value for Offset, the distance
between the upper edge of the wellhead and the earth’s surface can be specified and
therefore taken into consideration during the calculation.
Water density / Calculate water density
Entering the water density (for example. fresh water (20 °C) = 998.2 kg/m3)
If the user does not know the water density, the software supports its calculation:
By clicking Calculate water density the following screen appears.
For the calculation we need the installation depth
(B), the depth to water (C) as well as the current
pressure value (D). The air pressure must also be
entered if the device does not compensate for it. If
the air pressure is not known, the sensor can be
taken out of the water and the air pressure can be
read out by clicking "Current value (P1)”.
Calculations take place according to the following
formula:
Current value (D)
water density = ------------------------
(B - C) * 9.80665
All conversions into water level values are made
with a constant value for gravity:
g = 9.80665 [m/s 2 ].
Clicking on Calculate starts the calculation. Click
OK to update the values in WriterWL and exit, or
click Cancel to return to the main program without
saving any changes.
Warning:
The correctness of the calculated water density is wholly dependent on the correctness of the depth
figures. It is recommended that the sensor be located in a minimum depth of 3m of water.
Set User-Values (only in Writer)
This dialog box enables the entry of 7 user-defined values: for
example, installation depth, water density, height above sea
level, fixed coefficient, etc.
These values are written into the file created by the Text-
Converter if desired. This file can then be imported to
Microsoft Excel and a macro can be created by the user to
further process these values.