Oxygen Concentrator
13
Microprocessor
The microprocessor is the only processing element of the CAIRE
Companion 5. It contains embedded software which is pro-grammed
with all of the parameters for alarm conditions and settings of the
concentrator. The microprocessor is directly respon-sible for the
following functions of the concentrator:
•
Cycling (timing) of the solenoid valve
•
Driving the LCD display
•
Controlling the audible alarm
•
Controlling the operational and warning LED lights
•
Reading input from the OCSI sensor (OCSI models only)
The microprocessor is programmed with the alarm thresholds
and trigger points, as well as the timing of the solenoid valve to
cycle between sieve beds. A diagram of the input and output of
the microprocessor is shown below in Figure 5. Each input and
output is described further in the following sections.
Figure 5: Microprocessor Operation Block Diagram
Solenoid Valve
The solenoid valve is connected to the circuit board’s microproces-sor
by a 4-pin connector. The microprocessor is responsible for sending
the signal to open and close the valves. This cycles the air through
alternating sieve beds for the PSA process. The timing for alternating
the sieve beds is programmed into the microprocessor.
LCD Display
The 6-digit digital LCD display is mounted on the PCB and is vis-ible
on the front of the concentrator. Its purpose is to continually count and
display the hours that the concentrator has been in operation and to
display alarm conditions. The LCD display cannot be re-set and
displays time to the nearest tenth of an hour.
Audible Alarm
The CAIRE Companion 5 contains an audible buzzer that is sur-face
mounted on the PCB. Its purpose is to alert users of alarm conditions.
The microprocessor detects alarms by reading the input from the OCSI
sensor and the mains power switch. When there is an alarm condition,
the microprocessor sends a signal to activate the audible alarm.
LED Lights
There are three (3)(OCSI) LED lights that are surface mounted on the
PCB. They are visible from the front of the concentrator and their
purpose is to alert the user of operating conditions or alarms.
The top LED indicator is green. It remains on at all times when the
power switch is in the “ON” (
|
) position and the electrical cord is
plugged in. A continuous green light indicates normal operation.
The next LED indicator will be red. This light will indicate mal-functions
with the device. When the microprocessor detects an alarm condition
from the power switch or the flow rate sensor, it will send a signal for
the red LED to illuminate. The red LED will indicate a system
malfunction, loss of power, or flow rate is out of specifications.
The bottom LED indicator will be yellow. This light will only indicate low
oxygen concentration. This LED will illuminate when the
microprocessor detects an alarm condition from the OCSI sensor. The
LED will be solid if the oxygen concentration is
less than 85%
. The
warning alarms section will describe these alarm conditions in detail,
and provide basic troubleshooting steps.
