Carbon Monoxide Alarm User Manual

Page 30
PhD
2
is capable of logging 3000 intervals of data. The
bottom line on the interval adjust screen calculates how
many hours of data logging are available with the
currently selected interval value. For instance, in the
example screen above an interval of 1 minute has been
selected. This interval allows 50 hours of data logging
before the PhD
2
memory is full. If an interval value of 30
seconds is selected, the following screen will be
displayed:
In the event the memory is full, the PhD
2
is designed to
hold-on to the most recent 3000 data intervals. In the
case above, that means the most recent 25 hours of
monitoring.
Selecting a longer sampling interval allows the retention
of more hours of data. If an interval of 15 minutes is
selected, the detector is able to log 750 hours of
monitoring data, making the PhD
2
ideal for long-term
sampling projects.
If datalogging is not desired, an interval setting of :00:00
will deactivate the datalogger.
When finished adjusting the sampling interval, press the
Cal button to move on to the next screen.
6.2.3 Baud rate
Baud rates determine the speed at which data is
transferred via the RS-232 port to a computer. The PhD
2
comes from the factory with the baud rate set at 9600.
This is the appropriate setting for interfacing with most
personal computers. Press the Cal button to move on to
the next screen.
6.2.4 Setting the date and time
This screen is used to set or adjust the PhD
2
internal
real-time clock and calendar date. A cursor will highlight
the value to be adjusted. Pressing the "+" and "-" buttons
will change the value. Pressing the Alarm button will
advance the cursor to the next unit. Check the settings
by pressing the Cal button. Quit and save the new
settings by pressing and holding the Cal button.
Pressing the MODE button at any point in the procedure
will return the settings to their former levels.
6.2.5 Exiting the Datalogging Adjust mode
When the PhD
2
is properly configured, press and hold
the Cal key to save the changes. A screen will briefly
announce that changes have been made and the
configuration updated.
Pressing the MODE button will cancel the changes and
save the previous configuration.
6.3 Downloading recorded data
PhD
2
record keeping capabilities are most useful when
used together with the Biosystems Personal Computer
(PC) Based Gas Detector Database software.
Although downloading the recorded data to a computer
file offers the most complete way to examine the data, it
is also possible to review data directly from the PhD
2
meter display. It is not necessary to interface the
instrument with a computer in order to review the data
through the meter. Reviewing recorded data directly
through the instrument display screen allows the user to
answer two very important questions. 1. Were my
workers using their instruments? 2. Did the atmosphere
have any problems?
6.3.1 Entering the Record Keeping Data
Transfer mode
The Record Keeping Data Transfer mode is entered by
turning the PhD
2
on while holding down the "-" key. (The
unit must be in the Technician mode prior to being turned
on. See Section 2.2.4.) The Record Keeping Data
Transfer screen will briefly appear.
6.3.2 Downloading recorded data to the
instrument screen
The Record Keeping Data Transfer screen is followed by
another screen which is used to choose whether the data
is to be downloaded directly to the PhD
2
screen, or to be
downloaded via the RS-232 port to a computer.
Pressing "+" tells the PhD
2
to download to the instrument
screen. The display briefly shows the following screen.
This will be followed by a screen which shows the most
recent monitoring session. (The most recent completed
session is always session number "0.") As an example: