Carbon Monoxide Alarm User Manual

Page 11
Chapter 2 Basic operation
This chapter will cover how to use the PhD
2
for safe work
in potentially hazardous atmospheres.
2.1 Overview of PhD
2
operation
The PhD
2
offers a choice of three modes of operation,
"Text Only," "Basic," and "Technician." Mode selection is
a function of how much information is required, the skill
level of the user, and the nature of the job.
Regardless of operating mode selection, the PhD
2
automatically remembers (logs) gas readings, as well as
other important information such as turn-on / turn-off
times, battery condition, and whenever the instrument is
calibrated. This information may be downloaded to a
computer to create a permanent record, or directly
displayed on the PhD
2
meter screen. Although it is not
necessary to make use of this saved information, it is
there and available to the user.
2.1.1 Turning the PhD
2
on
The large black push-button on the top of the PhD
2
case
is called the MODE button. It is used to turn the PhD
2
on
and off, as well as to control most other operations of the
instrument. Pushing the MODE button once turns the
PhD
2
on.
2.1.2 Start-up sequence
After the detector has been turned on, it will automatically
go through an electronic self test and start up sequence
that takes approximately twenty seconds. During the self-
test sequence, the meter display back-light will
momentarily turn on, the visual LED alarm lights will
flash, and the audible alarm will sound. During start-up
the LCD display will also display several messages or
"screens" in sequence.
The first screen displays the software version number.
The second screen shows time and date.
The third screen shows the PhD
2
is conducting an
electronic self-test.
If the instrument has been turned on while in the "Basic"
or "Technician" mode, three additional screens are briefly
displayed. (These screens are omitted in the Text Only
mode start-up sequence.)
The first shows clock time, number of data points saved,
temperature, run time, and battery voltage:
The second shows the PhD
2
data memory being
checked:
The third shows sampling interval and duration for
memory:
At the end of the start-up sequence, the last screen will
display current gas level readings.
2.1.3 Turning the PhD
2
off
Holding the MODE button down for three seconds turns
the instrument off. In order to prevent accidental shut
downs, the MODE button must be depressed for a full
three seconds in order to turn the instrument off. After
three seconds (marked by three beeps of the audible
alarm) the LCD display will display the message "Release
button."
If the button is released prior to the "Release button"
message being displayed, the instrument will not turn off.
After the button is released the LCD display will display
the message, "Begin SHUT DOWN Please wait."
During the shut down sequence the PhD
2
is checking that
all data is properly stored in memory. The shut-down
sequence is complete when the meter display blanks out
in about ten seconds.
2.2 Operating modes
The PhD
2
offers a choice of three modes of operation,
"Text Only," "Basic," and "Technician." Which mode is
selected is a function of how much information is
required, the skill level of the user, and the nature of the
job. Whatever operating mode is selected, the PhD
2
automatically remembers (logs) gas readings, as well as
other important information such as turn-on / turn-off
times, battery condition, and whenever the instrument is
calibrated.