Sedona XPRESSion Evaluator Reference Guide

Physical Units Calculations

The XPRESSion Evaluator comes with an extensive library of built-in physical units. Several easy-to-use VIs provide the user with great flexibility in defining, customizing, and storing physical unit information. Associating units like meters (m) or frequency (Hz) with a variable is an important capability in many engineering and applied science applications.

Complicated expressions involving many variables that represent a physical quantity can be tedious to deal with if one wishes to gain insight into the physical units resulting from calculations. Checking the resulting units of such an expression is one of the most common and effective ways to expose user-entry errors in the expression or logical/numerical inaccuracies. The XPRESSion Evaluator automatically performs these tedious calculations for the user.

Even more flexibility is provided by an intuitive interactive utility that allows the user to create, describe, and store customized physical units for a particular application. Some simple examples below will show how these custom units can be arbitrarily complex and defined in terms of the fundamental built-in physical units and/or in terms of other user-defined units. This capability is very similar to the customized user functions described earlier in the Custom User-Defined Functions section.