ABB Endura AZ20 series, Руководство пользователя

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Endura AZ20 series probe
Combustion oxygen monitor 4 Connections
IM/AZ20P–EN Rev. G 23
4.4.4 Test Gas Inlets
Two test (calibration) gas inlets are provided for in situ AutoCal
probe testing using a test gas.
If AutoCal is not fitted, Test Gas 1 connection is used for Test
Gases 1 and 2. The gas connections are switched manually, as
requested by the calibration sequencing in the transmitter.
If the probe is connected permanently to the test gas supply
pipework:

fit a high quality, corrosion-resistant (stainless steel),
solenoid valve, manually operated valve or non-return
valve (that is leaktight even at zero back-pressure) in the
pipework, as close to the test gas inlet valve as possible

keep the valve closed when the calibration system is not in
use
Note. Test gas connection to non-AutoCal transmitters is
made to the external TG1 connection only. TG2 connection
is blanked off permanently.
Fig. 4.6 Test Gas Connections –
Endura AZ20 Probe with Remote Transmitter Shown
Test Gas 2
Inlet
(AutoCal
Use Only)
Test Gas 1
Inlet
External
Earth Point
Blanking plugs
(supplied) must be
fitted in any unused
Test Gas lines
Caution. If the test gas connection is not sealed when not
in use, air leaking into the probe via the connection causes
measurement errors. In a pressurized flue, gases venting to
atmosphere through the connection cause corrosion of, and
/ or block, the test gas tube. In a negative pressure flue, air
leakage causes high O
2
reading errors.
Note. It is preferable to use air (20.95 % O
2
) as one of the
test gases as this is the sensor’s zero point. Alternative
representative gases can be used according to local
environmental conditions.
To ensure better accuracy, use 2 test gases that represent
the top and bottom limits of the known operating range.
Due to resolution accuracies, do not calibrate the system
with gases of less than 1 % O
2
.