
Chapter 3 _______________________________________________________________ Installation
VAISALA _______________________________________________________________________ 67
observation period, the module stores the minimum and maximum values
during the interval, as well a data trend value that is averaged from
samples taken during the interval (see Table 9 on page 67).
Table 9 Observartion Periods and Resolution
Observation Period Period for Trend/Max/Min
Calculations (Resolution)
3 hours 90 seconds
1 day 12 minutes
10 days 2 hours
2 months 12 hours
1 year 3 days
4 years 12 days
The quantities that are logged are the same that have been selected for
measurement using the display/keypad or the serial line. When taking the
transmitter into use, verify that the desired quantities are selected. If you
change the quantities later, the transmitter will start logging the new
quantities, and stop logging the quantities that are no longer selected.
Changing the quantities does not delete any measurement data that is
already in memory.
The data logger module has a real time clock with a battery back-up. The
clock has been set to the Coordinated Universal Time (UTC) at the
factory, and its time cannot be set by the user. The data that is stored in
the logger's memory is timestamped using the logger's clock.
When date and time are set on the transmitter, they are stored to the
transmitter's memory as an offset from the time on the logger's clock.
When browsing the stored data, the time offset is applied to the
timestamps shown in the graphical history, and data outputted from the
serial port. The timestamps in the data logger's memory remain as they
were originally stored.
You can compensate for the clock drift (less than ±2 min/year) by setting
the time on the transmitter. This updates the time offset used on the
display and the serial port. You can set the time by using the
keypad/display or the serial commands.
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