Rae QRAE PLUS PGM-2000, Руководство по эксплуатации и техническому обслуживанию

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OPERATION
2-1
2. Operation
The QRAE PLUS Monitor is a compact multi-gas monitor. It gives real
time gas measurements and alarms when gas levels exceed the preset
limits. Before leaving the factory, default alarm limits are preset into the
QRAE PLUS and the sensors are pre-calibrated with standard
calibration gases. However, the user should calibrate the instrument
before the first use to guard against changes during shipment. Once
the monitor is fully charged and calibrated, it is ready for operation.
Calibration Frequency
The monitor should be calibrated before each day's use unless
experience in the application shows that less frequent
calibration meets the accuracy requirements for the job. In lieu
of a full calibration, a "bump check" with calibration gas can be
performed to ensure that the sensor(s) respond within the
accuracy limits established by the user. If the bump check fails,
a calibration must be performed. Frequent replacement of
external filters may help extend the required calibration interval.
Sensor Cross-sensitivity and Deactivation
After calibration, all sensors will accurately read the gas for
which they were designed and calibrated. However, all sensors
can exhibit interferences or deactivation under more or less
extreme conditions or concentrations. The user should always
be aware of potential interfering compounds or deactivators and
attempt to avoid such conditions. In particular, LEL sensors can
be deactivated by silicones and compounds of chlorine,
bromine, lead, phosphorus and sulfur. Percent levels of polar
organic vapors (e.g., alcohols & acetone) reversibly affect some
electrochemical sensors, particularly H2S and CO. High levels
of ammonia will shorten the life of the ammonia sensor.
Extremely low or high humidity may dry out or flood
electrochemical sensors and should be avoided for extended
periods. Indications that a sensor is nearing the end of its life
are given by a) an expiration date warning on start-up, b) an
error message during calibration or an inability to calibrate, and
c) noisy readings in a clean atmosphere.