6
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Calibration of the Instrument for Measurement Analysis
Section
Section
Thermo Scientific
Orion 2295 Phosphate Analyzer
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33
The menu screen shows two columns labeled REFERENCE and CURRENT. The data in the
current column is the active data being used for slope and intercept, and the data in the
reference column is the data that the system relies on when comparing the new calibration result
to check its allowed deviation per the specified limit specified for the tolerance value.
High Range Dilution-Factor Calibration
Please consult factory before proceeding with high concentration range calibration. This function
is disabled by default.The Monitor uses dilution method for measurement of concentrations
above its set range. The cycle is automatic and has been programmed at the factory. In most
cases the factory default values are sufficient for the specified range of the product. For
improved accuracy, the user may calibrate the dilution factor using a high concentration
standard like a 100 ppm. This calibration is only allowed in manual mode, with user prompts and
confirmation required at the end of the cycle. Extended range calibration:
MENU
➔
SETUP
➔
(+) CALIBRATION PARAMETERS
Set the STANDARD CONC = 100 ppm and calibration:
MAIN MENU
➔
MEASUREMENT
➔
CALIBRATE
➔
CALIBRATE STANDARD
When the system detects a high absorbance level of the reacted solution, above the set limit, it
initiates the dilution cycle using the standard.
At the end of the cycle the dilution factor is calculated based on the value of the standard used
and the existing slope and intercept.
At the end of the calibration cycle the user is presented with the new calculated dilution factor to
accept or reject. The default dilution factor is 9.0 (range 8 to 10). The range depends on the
pump flow rate (pump #1) used to add the standard used for dilution dosing.
The user may edit the dilution factor in the ANALYSIS PARAMETERS menu:
MENU
➔
SETUP
➔
ANALYSIS PARAMETERS
➔
(+) (+) PAGE 3 OF 4
➔
DILUTION
PARAMETERS
Consult the factory before modifying the default dilution steps. Press (+) to access the dilution
steps.
The automatic dilution cycle may be turned off using either a higher than expected AU limit:
ABS HIGH LIMIT= 5 AU or by de-selecting the dilution event
DILUTION EVENT = NOT ASSIGNED
During the analysis of high concentration samples, the system checks the final absorbance
value of the reacted solution and if it exceeds the set limit (ABS HIGH LIMIT) it will execute the
dilution steps and use the calibrated dilution factor to calculate the final concentration.
