BUCHI DuMaster D-480 - Manual (Page 53)

Operation Manual D-480 ©BÜCH Labortechnik AG
4 - Understanding the instrument and planning its use 53
 The daily factor for a measuring component is clearly outside of the range of 0.9 to 1.1. Also, it
displays fast changes in time from day to day.
Calibration formulae
The formulae used for calibration can be found in Calibration formulae (on page 55).
Calibration curve calculation method
For details on the various calibration curve calculation methods and when to use them, see
Calibration curve computation method criteria (on page 53).
Notes on performing calibration
For details on practical implementation of calibration, refer to
 the section Performing calibration.
 the calibration tables.
Calibration curve calculation method criteria
Calibration curve configuration options
The user can specify the calibration curve calculation method according to the following criteria:
 Calibration can be performed over the whole measuring range either consistently or in two
ranges.
 For a specific element content you can set a dividing line for two calibration ranges.
 For each range, you select a polynomial degree according to which to compute the calibration
curve (linear to 4th degree).
Calculation criteria
Look to the calibration view of the combi view for calibration curve calculation method criteria. You get
to the calibration view after performing or loading a series of defined calibration samples by selecting
Calibration > Calibrate... and then the "Configuration calibration" dialog.
Ideal calculation method
If possible, try to compute calibration curves so that they
 are uniform over the whole measuring range and/or concentration range
 and can be displayed in linear form or on the basis of a polynomial of the lowest order.
To facilitate selecting a calculation method, four typical calibration graphs are shown below along with
the suitable calculation method.
Note: For better understanding the calibration graphics are shown in a simplyfied way.