Dimensional units define how data values are interpreted by apiMAX. All data values are saved in internal units. Input data values are converted to internal units from user defined I/O units. Output data values are converted from internal units to user define I/O units. New I/O Units can be added or new Unit Types can be created.

To change the units of measure

• Click the right mouse button in an empty area of the Model Window.
• Select Properties and select the Unit Types tab.

• Select input/output units (I/O Units) by selecting the unit type in the Unit Types list and then selecting the input/output unit in the I/O Units list.
• All data values of the selected type will be input and output in the selected dimensional units.
• For example, internal units for Mass Flow are lbs/hr.
• Select t/day for Mass Flow I/O Units.

• All input flow values are converted from t/day to lb/hr and all output flow values are converted from lb/hr to t/day.

• Dimensional units conversion is done using a multiplier and a bias.
• Internal Units = I/O Units * multiplier + bias
• For example, lbs/hr = t/day * 2.20463 + 0.0.

To add I/O Units

• Click the New button at the top of the I/O Units list.
• Enter the unit name and press the Enter key.
• Enter the multiplier and bias that convert the new I/O Unit to internal units.

Adding Unit Types

• Click the New button at the top of the Unit Types list. Enter the unit type name and press the Enter key.
• Add I/O Units and select the Internal Units for the new unit type.

To delete unit types

Do Not Change the Internal Units for existing Unit Types. Models assume that the internal units for values will never change.

Do Not Delete existing Unit Types. Models use these Unit Types.

• You can delete any I/O Unit except the Internal I/O Unit.

• Delete an I/O Unit by selecting the unit and click the delete button.
• You can reorder either the Unit Types or I/O Units by making a selection and clicking the Move Up or Move Down buttons.