Xylem DH-21 - Manual (Page 21)

DH-21
Using the “W ATER LOG” Software 3-3
The Memory Used field indicates what percentage of the FLASH EEPROM currently has been
filled. The FLASH EEPROM has 128 K bytes of storage. The FLASH EEPROM will not lose
data in the event of a power failure and does not depend on a battery to maintain its data. This
makes it ideal for remote, unattended data logging.
The Logging Count indicates the number of samples stored by the “ W
ATER LOG”. The
maximum count is 10,922 counts with a 128 K byte FLASH EEPROM installed. If a sample is
taken every hour, the “
W ATER LOG” will store 10,922 hours worth of data. Dividing 10,922
hours by 24 provides 455 days of sampling. Care should be taken when specifying the sample
rate to determine how many samples can be taken, and also to determine how long the batteries
will last.
The battery voltage is shown on the computer screen to help you know when the batteries should
be replaced. A reading of 7 Volts indicates a good battery, and a reading of 5.5 Volts or lower
indicates the battery should be changed. If an external battery is used, it could be as high as 16
volts, but must not exceed this level.
The section in the middle of the screen is a help menu containing the command options which
are used to initialize and use the “
W
ATER LOG” sensor/logger. You can invoke each option by
typing the number of the option and pressing the ENTER Key on the computer.
The blank section at the bottom of the screen is used for software interaction with the user.
Various information and options are displayed in this section.
The upper right window displays the results of the last measurement of the sensor. The scaling
and user units are explained in this chapter.
A “ W ATER LOG” sensor MUST be connected in order for the status information and options to
work.