10 • Chapter 2: Description
04 Series for CO(-H2)
Control Buttons
Two control buttons, AIR and POWER MODE, are located below the LCD.
Alarm LED
The alarm LED above the LCD alert you to gas, low battery, and failure alarms.
Buzzer
One solid-state electronic buzzer is located inside the case. Sound exits the case through a
hole in the upper left corner of the front case. The buzzer sounds for gas alarms, malfunctions,
and low battery voltage. It also provides feedback for button presses and while in Display,
User, Maintenance, or Gas Select Mode.
Vibrator
A vibrating motor inside the CO-04C case vibrates for gas alarms and unit malfunctions.
NOTE:
If
STEALTH
is set to
ON
, the vibrator only functions when
VIB
in the
STEALTH
Gas Select Mode item is set to
ON
(see pg.91).
Sensor
The CO sensor is an electrochemical cell that consists of two precious metal electrodes in a
dilute acid electrolyte. A gas permeable membrane covers the sensor face and allows gas to
diffuse into the electrolyte. The gas reacts in the sensor and produces a current proportional to
the concentration of the target gas. The CO-04C’s circuitry amplifies the current, converts the
current to a gas concentration, and displays the concentration on the LCD.
This sensor does not respond to or responds minimally to hydrogen (displays H2 RICH once
H
2
concentration reaches 2000 ppm).
Table 3: CO-04C Control Button Functions
Button
Function(s)
AIR
• turns on LCD backlight
• resets alarm condition if
LATCH
is set to
ON
in Maintenance Mode
• enters User Mode, Maintenance Mode, and Gas Select Mode when used
with POWER MODE
• activates the demand zero function (adjusts the CO-04C’s fresh air reading)
• changes the value of a parameter available for adjustment
• scrolls through parameter options
POWER MODE
• turns the CO-04C on and off
• turns on LCD backlight
• enters and scrolls through Display Mode
• enters instructions into the CO-04C’s microprocessor
• resets alarm condition if
LATCH
is set to
ON
in Maintenance Mode
• enters User Mode, Maintenance Mode, and Gas Select Mode when used
with AIR