Chapter 1 TriLog
15
1.2.5. The
Display
The Alfa numeric 2-lines LCD screen displays TriLog
’
s setup and status messages
and shows measured data in recording rates up to 10 per second.
To scroll through the various data displays press the
Rate
button.
In standby mode the display is turned off except for a brief period of time once a
minute to display status.
In power saving mode the display is turned off except for a brief period every time
TriLog records a new sample only to display the sample number.
If the user incidentally presses the on button in power saving mode TriLog displays
warning message:
To stop logging:
Press STOP
1.2.6.
Load the Last Setup
When you turn TriLog on, once the self testing and selection of the input modes has
been completed, it will automatically load the last setup you
’
ve used.
1.2.7.
Internal Clock and Calendar
The internal clock is set the first time you use the
Setup
command from the MultiLab
software to program the TriLog, and is automatically updated to the PC
’
s time and
date each time you connect your TriLog to a PC.
The internal clock and calendar is kept updated even when the TriLog is turned off,
but it will be erased if the 2.4V battery is dead. It will be updated the next time TriLog
will be connected to a computer or a Palm.
1.2.8.
Clear the Memory
TriLog automatically checks the available memory before it begins the recording. If
there is not enough memory you will see this message on the display:
_ _ _ LOGGER-RUN _ _ _
Clear = (Run)
Press the
Run
button to clear the memory and begin recording.
1.2.9.
Choose the Right Setup.
1.Sampling rate
The sampling rate should be determined by the frequency of the phenomenon being
sampled. If the phenomenon is periodic, sample at a rate of at least twice the
expected frequency. For example, sound recordings should be sampled at the
highest sampling rate
–
20,800/sec, but changes in room temperature can be
measured at slower rates such as once per second or even slower, depending on the
speed of the expected changes. THERE IS NO SUCH THING AS OVER-
SAMPLING. For extremely smooth graphs, the sampling rate should be about 20
times the expected frequency.