Measurement and Analysis
Vivid S5/Vivid S6 User Manual 349
R2424458-100 Rev. 2
About units
Be aware of the following:
• All units are calculated in SI units (see table below).
• If no unit is specified in the Edit formula window when
defining a formula, the displayed value will be in SI unit.
To define a different unit
1. When creating a formula, enter the unit to use when
displaying the formula output. E.g. if Y in the formula Y=f(x)
is to be displayed in cm, enter cm in the Unit field.
The Unit field is case sensitive, make sure to enter the
exact unit as shown in the table below (Alternative unit
column).
2. The output of a formula must always be in an SI unit (see
table below). Conversion to the specified display unit is then
done automatically.
Example: a user wants to add a regression formula for
estimating a length B from a measured length A, both in
cm.
The formula is: B = 2.4 + 1.1*A.
• As A is a measurement value the system will enter the
formula in the SI unit for length (m). The formula expects
A in cm, and to get that, A must be multiplied by 100:
B = 2.4 + 1.1*A*100
• The formula now gives B in cm. Converting the output
from cm to the SI unit (m), is done by dividing by 100:
B = (2.4 + 1.1*A*100)/100
The output is now in m, and by entering this formula into
the system the user gets the expected result. Measuring
an A of 2 cm gives:
B = (2.4 + 1.1*0.02*100)/100 = 0.046 m.
Before display of the value it is converted according to the
specified display unit (cm), and the system displays 4.6
cm. If the selected display unit was set to mm the formula
would give the exact same output, 0.046 m, but the
automatic unit conversion would now instead give a
displayed value of 46 mm.
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