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<9. CALIBRATION>
9-2
IM 11P03A03-01E 6th Edition : Jan. 26, 2022-00
Span calibration coefficient
=
k’
k
Where:
k
: the ratio of the oxygen concentration to the sensor emf obtained at the initial calibration
k’ : the ratio of the oxygen concentration to the sensor emf obtained in calibration
When the span calibration coefficient is outside the range of 0.9 to 1.09, a span calibration
coefficient error will occur.
9.2.3 Checking the Calibration Coefficients
(1) Switch to MAINT mode. There is no need to enter the password.
(2) Change the Function Number to “03.”
(3) Press the ZERO key to check the zero calibration coefficient, and press the SPAN key to
check the span calibration coefficient.
9.2.4 Initializing the Calibration Coefficients
By initializing the calibration coefficients, the zero calibration coefficient is reset to “0” and the
span calibration coefficient to “1.” Based on the sensor emf obtained in the next calibration
after the initialization, the calibration coefficients will be calculated. The calibration after the
initialization should be performed with special care.
(1) Switch to MAINT mode and enter the password.
(2) Change the Function Number to “05.” The DATA display shows “rES.”
(3) Press the EXEC key to initialize the calibration coefficients.
CAUTION
• The calibration coefficients disolayed in Function No. 03 are still the previous ones after the
initialization.
They will be updated only after zero and span calibrations after the initialization.
• When the concentration of the zero gas is changed in Function No. 02, the zero reference
will be changed.
Accordingly the calibration coefficients will be initialized: this is the same action as the
initialization by the above procedure.
9.3 Executing Calibrations
Zero and span calibrations must be performed after the power is turned off and restarted. Without
valid calibration oxygen concentration cannot be measured accurately. Before calibration, the
following should be checked.
(1) The auxiliary gas is being supplied at the specified pressure.
(2) Auxiliary gas and zero gas with proper nitrogen purities are used.
(3) The span gas concentration set in the instrument agrees with the actual gas concentration.
(4) Calibration gases flow at the specified flow rate without fluctuation.
9.3.1 Manual Calibration
A zero calibration should be performed first, and then a span calibration. A span calibration
cannot be executed before a zero calibration. It is allowed to perform only a zero calibration, but
not allowed to perform only a span calibration.