Option 3.2.1. Equation

Select Equation in the Calculation field on the Virtual tab of the Point Properties dialog box.

1	Expression field

The expression may contain:

One or more Point IDs along with

Constant values, operations, and functions.

Rules for defining an expression are:

Rule	Description
Avoid introducing loops (circular references between points) in your expressions.	Example of what to AVOID: VIRTUAL_PT1 = DEVICE_PT + VIRTUAL_PT2 VIRTUAL_PT2 = DEVICE_PT + VIRTUAL_PT1
	Although this will not cause CIMPLICITY software to fail, it will cause the Virtual Point Processor to always have work to do. This causes all available computer time to be consumed, which adversely impacts system performance.
Use proper formatting for array points.	Example of the correct format: VIRTUAL_PT1 = DEVICE_PT[0] / 2.0
Use proper formatting for Point IDs with reserved words.	Point IDs that are reserved words, or contain spaces, arithmetic operators, parentheses, or that begin with a non-alphabetic character must be placed in single quotes when used in an expression. Example VIRTUAL_PT2 ='DEVICE_PT:0' * 'WARNING_LOW'

Buttons to help with the equation are as follows.

Displays a Popup menu to:

Open:

The Select a Point browser.

The Point Properties dialog box for a selected point.

A New Point dialog box.

The Expression Editor.

Display an extended menu with the associated operations.

2	Reset Point

(Optional) When a Reset point is selected the Equation point is reset as follows during runtime.

When the trigger point is not defined:
If	And	Then
An Initial Equation Point value is	The Current value of the Expression is	The Equation point value is reset to the
Not defined	Available	Current value
Not defined	Un available	Zero
Defined	Unavailable	Initial value
Defined	Available	Current value
When the trigger point is defined:
If		Then
An Initial Equation Point value is		The Equation point value is reset to the
Not defined		Zero
Defined		Initial value

Note: Buttons to the right of the Reset Point and Trigger Point fields help with configuration.

Opens the Select a Point browser to select an available point.

Displays a Popup menu to:

Open:

A New Point dialog box.

The Point Properties dialog box for a selected point.

The Select a Point browser.

Select a recently selected point.

3	Trigger Point field

(Optional) When the value of the equation updates depends on whether or not you defined the trigger point.

Trigger point	The value of the Equation point is updated whenever Value of the:
Defined	Trigger point is updated.
Not defined	One of the source points in the Expression field is updated.

Buttons to help with the trigger point have the same functionality as the buttons to the right of the Reset Point field.

Step 3.2. Configure virtual calculations.