PureAire Monitoring Systems, Inc.
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4: Normal Operation
The Universal Gas Detector is a single point monitor designed for the continuous detection and
measurement of ambient toxic and corrosive gas concentration levels.
4.1 Signal Outputs
The Universal Gas Detector outputs a continuous 4-20 mA analog signal proportional to the measured
concentration of toxic or corrosive gas. 4 mA represents 0 ppm and 20 mA represents full scale ppm
of the gas being detected. 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 Universal Gas Detector
incorporates a number of self-checking features to
ensure reliable operation. In the event that 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
Sensor cell cable cut
Analog output drops to 2 mA
***Communications Error
with Sensor Cell Missing
Fault Code 01
Analog output drops to 2 mA (0 mA on request)
Fault Relay activates
System Warm Up
Analog output drops to 2 mA
Fault Relay activates and turns off when system
is in the measurement mode
NOTE: If a Fault condition clears itself, (Yellow LED is no longer illuminated)
The Fault message will continue to scroll until manually cleared.
To clear the fault message, push the joystick down (- Minus)
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 insure 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.
*** If the monitor is in alarm Do Not unplug the Sensor cell. If the
monitor in in alarm and the sensor cell is unplugged, the alarms
and audible horn will remain activated. Resetting the alarms will
require a complete power down.
