The calibration formula editor allows you to enter an individual formula
for calculating a result value for a physical property from spectral data.
All intensity values, peak heights or peak areas might be addressed in
a custom formula for calculation. Furthermore it is possible to use data
stored in custom labels attached to data objects in use.
The calibration formula editor looks like this:
Enter any formula using simple arithmetic operations into the text field.
If you are not sure about the syntax, please use the short
hand buttons underneath the text field or the context menu available
on Right
Mouse button click for
assistance.
Context menu
To open the context menu, giving access to all functions listed below,
please follow the instructions:
Move the mouse
pointer to the position in the text field, where you like to insert
a parameter, operator, mathematical function or label.
Click the Right Mouse button to open the context menu.
The following values, variables, mathematical functions and operators
are allowed to create a formula:
Values
Positive or negative numeric values
Spectral Macros
Intensity values at a defined position on the x-axis
of the current set of calibration spectra. For assistance, please click
the Intensitybutton.
Peak area of a defined peak position within the current
set of calibration spectra. A peak will be defined by a starting and an
ending position on the x-axis. The peak area will be calculated as the
area between the baseline of the peak and the graph of the spectrum. The
baseline of the peak is meant to be a straight line between starting and
ending point of the peak. For assistance, please click the Peak
Area button.
Peak height of a defined peak position within the current
set of calibration spectra. A peak will be defined by a starting and an
ending position on the x-axis. The peak height is determined from the
maximum intensity value within the peak range with respect to the baseline
of the peak. The baseline of the peak is meant to be a straight line between
starting and ending point of the peak. For assistance, please click the
Peak
Height button.
Absolute peak height. Same as the peak height function
but returning the absolute peak height.
Any additional information stored in custom labels of
the data object are available on the Label button.
If the user has stored additional information like concentrations,
dilution factors, etc. in labels, he can use them in calculation by selecting
the respective label. Click the button to show a list of all available
labels.
Mathematical functions
Default mathematical functions from a pocket calculator like sin(x),
cos(x), tan(x), sqrt(x), sqr(x), etc. are available in the context menu
of the editor.
Tags
Tags are defined variables for a given spectrum. Available tags are
the minimum and maximum data values of the x-axis and y-axis.
Operators
A list of operators is given as buttons below the formula text field.
They are also available in a context menu.
Any basic mathematical operators are allowed to add,
subtract, multiply or divide values. For assistance, please click one
of the operator buttons.
Mathematical terms can be put in parentheses to control
the order of calculation.
Example:
The ratio between the intensity at a desired x-axis value and the height
of the underlying peak in this area must be evaluated. Spectral data needs
to be corrected by a dilution factor, which has been retrieved in previous
"wet chemistry" analysis. The dilution factor was attached to
the data objects in a label called "Dilution Factor" and can
be used in the formula now.
