10 • Chapter 2: Description
SC-04
Control Buttons
Two control buttons, AIR and POWER MODE, are located below the LCD.
Alarm LED
The alarm LED above the sensor and buzzer openings alerts 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 SC-04 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.89).
Sensor
The 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 SC-04’s circuitry amplifies the current, converts the
current to a gas concentration, and displays the concentration on the LCD.
Each target gas has its own sensor.
Table 3: SC-04 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 SC-04’s fresh air reading)
• changes the value of a parameter available for adjustment
• scrolls through parameter options
POWER MODE
• turns the SC-04 on and off
• turns on LCD backlight
• enters and scrolls through Display Mode
• enters instructions into the SC-04’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