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40
Calibrations
6.4 Sensor calibration
When delivered, the sensor is pre-calibrated. However, it should be re-calibrated on site, when
being used for the first time, and always after a membrane change. If you have just replaced the
membrane, allow at least half an hour for the membrane to settle before attempting to calibrate.
If you want to verify the accuracy of the calibration, place the analyzer back in measurement
mode and compare your displayed gas concentration against the value in the appropriate tables
found in the accompanying Calibration Tables booklet.
Your calibration is stored internally and is valid for the life of the sensor's membrane, thus it is
not necessary to repeat the calibration procedure until after the next membrane change.
The sensor can be calibrated either by using a span gas or directly in line in a liquid sample.
Additionally, oxygen sensors can be calibrated in air. The mode of calibration may be selected
using the WinLog97 program or directly from the instrument (refer to
for more details).
6.4.1 Calibration in a span gas
The span gas calibration procedure may be used if you have a supply of gas with a known
concentration in %units (use O
2
for oxygen sensors or H
2
for hydrogen sensors). To perform
this type of calibration, the instrument must be set for calibration
In a Span Gas
. The WinLog97
program also must be used in this procedure to set the gas concentration parameter.
Switch on the instrument, if necessary, and wait a minute or so for the displayed measurement
to settle. Then expose the sensor to a span gas sample with a known gas concentration. Enter
the percentage of gas in the span gas using the WinLog97 program (refer to
).
1.
Press the
CAL
button. Remember, this button may have been
locked out to prevent an accidental reset (refer to
the instrument’s CAL button on page 37
for details).
2.
A brief clearing
[---]
message appears.
3.
Press
CAL
again within a 3 second period.
4.
The percentage of the measured current to the ideal one is
displayed.
5.
When the reading is stable, press
CAL
again.
If the new calibration current is within 25% to 175% of the ideal
current
, the instrument displays
CAL
and returns to the
measurement mode. Calibration is now complete, the sensor is
calibrated, and you can proceed with your measurements.
If the new calibration current is not within this range
, the
instrument displays
Err
and returns to measurement mode. The
system will not calibrate, and it is likely that a sensor service will
be required.
Summary of Contents for ORBISPHERE 3650 Atex
Page 1: ...DOC024 52 93004 ORBISPHERE Model 3650 Atex USER MANUAL 10 2019 Edition 13...
Page 2: ...2...
Page 12: ...10 General Information...
Page 24: ...22 Installation...
Page 34: ...32 Operating Information...