Units Conversions

The calculator has in-built units conversions and constants. Using conventional calculators and reference books it is often difficult to find a conversion factor between the pair of units you are dealing with and you are forced to convert in several error-prone steps. This problem is eliminated with the units conversion facility. The conversion function also eliminates the risk of confusion about 'which way' to use a factor that arises when converting between different units systems of dimensionally complex quantities.

Suppose you have a value for a property, dynamic viscosity say, quoted in non-SI units, and the formula you are computing is in SI. First, enter the value into the calculator display. Next, click the unit button and select the property dynamic viscosity from the Properties box. Then in the From box select the set of units in which the value has been entered (e.g. slug/ft-sec), by clicking on the down-arrow to the right of the box. Now select the desired units in the To box. If the desired units are SI, you can just click the SI button, rather than searching for them in the drop-down edit box. Finally click the OK button (or return on the keyboard) and the converted value will be shown in the calculator display. Click the Cancel button to return to the calculator without performing any conversion. To use the same conversion on another value, enter the new value and select unit again. Click OK or press return to use the same conversion on the new value.

You can use the Find button to search for a property or units from the properties database. Click on Find and enter the word or part word you are looking for. The first property or unit containing the word will appear in the convert dialog box. Press the Find Next button to find any further occurrences of the word.

To modify the properties database press the Edit button next to the properties or units. A dialog appears which allows you to Add, Delete or Rename units or properties. For units you can also update the factor or offset (for example if you have access to more accurate data). Select the units or property you want to rename or delete in the listbox.

You can save your updated properties and units by clicking the Save button and giving a file name. You can subsequently load a set of properties, units and constants using the Load button or as described below. If you save the file with the name DEFAULT.PRP in the default directory, your file will be loaded automatically in future. The file FACTORY.PRP is the properties file which is supplied with the software and should not be overwritten. If you want to revert to the properties as supplied, simply delete or rename your DEFAULT.PRP file; FACTORY.PRP is automatically loaded if DEFAULT.PRP is absent. If you have saved a lot of data in this way, you might want to make sure you have a backup copy of your DEFAULT.PRP file.

Loading External Properties and Constants

The calculator has a number of properties and constants built in. Additional properties and constants are stored in an external file, as described above. You can obtain these files externally or distribute your own. Also, to save application loading time if this becomes significant, you can avoid loading the more detailed sets of properties until they are needed.

To prevent automatic loading of properties and constants from an external file, ensure you do not have a file called FACTORY.PRP or DEFAULT.PRP.