Carbon Monoxide Alarm User Manual

Page 25
5.2.2.1 Optimal diagnostic count ranges for
version 4.7 PhD
2
detectors
Sensor Min. Max.
O2 595 935
LEL 200 275
CO 24000 36500
H2S 24000 36500
SO2 24000 36500
NO 21500 36500
NO2 24000 36500
Cl2 24000 36500
NH3 21500 36500
HCN 24000 36500
HCl 20500 36500
TOX 1 20500 36500
5.2.3 Exiting the Diagnostics Test mode
The Diagnostics Test mode is exited by turning the PhD
2
off. This is done in the usual manner by holding down
the MODE button for 3 seconds.
5.3 Sensor Configuration mode
The PhD
2
can be configured as a one, two, three, or four
gas monitor. Changes in the number and types of
sensors are made while in the Sensor Configuration
mode. Sensors can be added, deleted, changed, or
replaced in the field.
The PhD
2
microprocessor circuitry eliminates the need
for manual switch setting and other laborious set-up
procedures. It is still necessary, however, to verify the
accuracy of the PhD
2
by calibration with known
concentration test gas whenever a change is made to the
sensors installed in the instrument.
Changes made while in the Sensor Configuration mode
will trigger a "Needs Cal" message the next time the
instrument is turned on while in a normal operation mode.
The LCD rotates between the "Needs Cal" message and
each type of sensor the instrument understands to be
currently installed. This message will continue to be
displayed any time the instrument is turned on in a
normal operation mode until all the sensors have been
successfully calibrated.
Pressing the MODE button to acknowledge the "Needs
Cal" alarm silences the alarms and allows the normal
operation of the instrument. Each time the instrument is
turned on the "Needs Cal" alarms will be activated until all
sensors have been successfully calibrated.
While in the Sensor Configuration mode it is possible to
re-program the PhD
2
with several alternative set-up
configurations including latching alarms, timed security
beeps, and assigning the instrument a user defined
identification number. Each of these options is discussed
in greater detail below.
5.3.1 Entering the Sensor Configuration
mode
The Sensor Configuration mode is entered from the
Diagnostics Test mode. Enter the Diagnostics Test mode
as described above in section 5.2.1.
Push the alarm button within three seconds of the display
of the first diagnostic mode screen to enter the Sensor
Configuration mode.
A screen will briefly announce that the sensor
configuration mode has been entered.
This screen will be followed by one showing the oxygen
enable / disable message.
5.3.2 Enabling and disabling the oxygen
and combustible gas (LEL) channels
The oxygen and combustible LEL channels are dedicated;
that is, no other sensor except an oxygen or combustible
sensor may be inserted into the sockets where these
sensors are located. The only decision that may be made
for these two channels is whether they are "enabled"
(turned on), or "disabled" (turned off).
Use the "+" and "-" keys to enable or disable the oxygen
channel.
If the oxygen channel is disabled, when the PhD
2
is back
in normal operation the gas reading screen will no longer
show an oxygen indication. To illustrate:
Gas reading screen with the oxygen channel turned on:
Gas reading screen with the oxygen channel turned off:
Press the Cal button once to advance to the combustible
gas enable / disable screen.