3. Virtual Point Expressions

There are several places in Virtual Points where you enter an expression as part of your configuration.

Whenever you are asked to enter an expression, you can use the:

• Point and Operation selections located to the right of an Expression box.
• Edit Builder.

Point and Operation selections located to the right of an Expression field

In the Point Properties window, to the right of the Expression box, select A menu opens with the following tools that help build expressions.

Option	Description
Browse Point ID	Opens the Select a Point window.
Edit Point	Opens the Point Properties window for a selected point.
New Point	Opens a New Point window.
Build Expression	Opens the Build Expression window.
Browse Historian Tags	Opens the Select a Tag window.
Alarm Functions	Displays extended menus with the expression operations and functions that are associated with the selected category.
Arithmetic
Bitwise Operations
Format String
Format Value
General
Historian
Logical Operations
Relational Operations
Scientific
Shape Attribute
Point By Address	Opens the Point By Address window.
System Sentry Points	Opens the System Sentry Address Builder window.

Select an operation to place it at the current position of the cursor in the input box. If the operation requires an argument, the cursor is positioned for you to type the argument.

Insert a point ID or variable either after the operator or between parentheses, if they appear with an operator.

• A point based expression can be up to 300 characters long.
• When you use a device Point ID in the Expression Editor for virtual points, the raw value of the point is used by default.
• If you want to use the engineering units value, enter EU_CONV(< point_id >) in the expression.

Expression Builder

For data items, when you select , the Edit Expression window as seen below appears.