Xylem DH-21 - Manual (Page 105)

Chapter 5
Guide to Data Analysis
DH-21
Guide to Data Analysis 5-1
Data is placed in a file on your DOS disk under the filename you specified with a “.DAT”
extension when using option 8 from the main menu, using the Generic WaterGEN.EXE program,
or using the Extract Option in the WaterLOG.EXE Program. Figure 5-1 shows the beginning
segment of a file extracted from the “
W
ATER LOG”. The first 18 lines of the file contain the
serial number of the logger, the time of data extraction, the time the logging session was started,
the sample rate, user notes, delta log value, hyper log value, and hyper divisor entered into the
“
W ATER LOG” when the logger was initialized. The next 3 lines contain the coefficients used in
the “ W
ATER LOG” to transform the data to the correct format for pressure and temperature. The
measurement data appears next in the file. Each line of data contains the date, time, Julian day,
pressure, temperature, and battery voltage for a given sample.
Normally, the FLASH EEPROM will contain all of the data. However, when the EEPROM is
full, the “
W ATER LOG” will begin writing over the oldest data. You can avoid losing data by
specifying a sufficiently long sample rate, or extracting the data from the “ W
ATER LOG” more
often. It is probable that a data wrap-around occurred if the Memory Used display shows 100.0%
when you attach the computer to the “
W
ATER LOG” for data extraction.
The data file can be read into your analysis software for the various plots and graphs you may
require.