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01115009A _9
Paracube
®
Micro – Instruction Manual
To correct the oxygen reading following a SPOC, you will need to measure the sample
gas pressure, and compensate using the expression for pressure compensation
detailed in method 3 of section 4.9. You should use a value of 100 for P
cal
reflecting
the factory calibration pressure of 100kPa and your measured pressure P
ind
must also
be in the same units. See caution 8.
Fig. 7
A SPOC can be initiated by depressing the on-board “Button Key-Press” located on the
sensor’s uppermost PCB.
During a SPOC the sensor’s millivolt output is driven between the full extents of the
configured range at a frequency of 1 Hz. The configured range is between -15% O
2
and 200% O
2
, so at 10mV/%O
2
output is driven between -0.15V and 2V. The oscillation
is triggered by acceptance of the button key-press and ceases following a
successful/unsuccessful SPOC.
Caution - No. 8
If your sensor has pressure compensation disabled, oxygen readings
following a SPOC may not reflect the known gas concentration. This will
be due to changes in sample gas pressure. The SPOC procedure
only
removes the drift component
from the oxygen reading.
Single Point Offset Correction Explained
Sample Gas - % Oxygen
Sensor
Output –
Oxygen
Reading
Oxygen Reading with Pressure
Sensor Enabled
Oxygen Reading with Pressure
Sensor Disabled
Pressure
Effect
Zero Drift
Effect
Factory Calibration @ 100KPa
