PureAire Monitoring Systems, Inc.
14
4: Normal Operation
The
CO
2
monitor is a single point monitor designed for the continuous detection and measurement of
ambient carbon dioxide concentration levels.
4.1 Signal Outputs
The
CO
2
monitor outputs a continuous 4-20 mA analog signal proportional to the measured
concentration of carbon dioxide. For CO
2
, 4 mA represents 0 PPM CO
2
and 20 mA represents 50,000
PPM CO
2
which is the full range for carbon dioxide. In the event of a system fault, a specific factory
defined code will be displayed on the local digital display. This code will indicate the exact nature of
the system fault.
4.2 Instrument Faults
The
CO
2
monitor
incorporates a several self-checking features to ensure reliable
operation. If a fault condition is detected, the analog output signal is altered: A
few common error codes are displayed in the following table:
Condition
Analog Signal
**Supply Voltage Out of
Range Fault code 16
Analog output drops to 2 mA
Fault Relay activates
Transmitter cable cut
Analog output drops to 0 mA
CO
2
Cell complete failure
Fault code 128
Analog output drops to 2 mA
EEPROM Fault 08
Analog output drops to 2mA Fault Relay activates
CO2 sensor not responding
Fault code F01
Analog output drops to 2mA Fault Relay
activates
4.3 Routine Maintenance Schedule
Continuous gas detection systems depended upon to measure and detect hazardous gas leaks in the
workplace requires periodic maintenance to ensure proper operation. The frequency with which this
routine maintenance is required depends on the environment. The following table is intended to serve
as a general guideline for routine maintenance. The conditions in your application, as well as your
organization’s maintenance policies, will ultimately determine the best routine maintenance schedule
for your equipment. Routine Visual Checks
NOTE
:
All system faults are displayed on the front panel. Each fault
has it’own specific code to identify the specific problem. Please
contact PureAire whenever a fault is displayed.
** When using your own power supply please ensure that the voltage
is regulated to 24VDC +/- 0.5 volts. If the voltage is too low or high
you will activate a “Supply Voltage Out of Range fault and disable
the monitor.
