Option 3.2.6. Min Capture

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

A Min Capture point maintains the minimum encountered point value for the source Point ID that you specify in the Expression field.

The minimum value is determined by comparing the current source point value with the value stored in the Min Capture point. If the current value is smaller, it is stored as the new Min Capture point value.

Important: Min Capture points are not supported in redundancy.

1	Expression
2	Reset point
3	Trigger point

1	Expression

Enter an expression that calculates the value of the Min Capture point.

The expression will be monitored for transitions.

The expression may contain:

One or more Point IDs along with

Constant values, operations, and functions.

Buttons to help with the equation are as follows.

Opens the Expression Editor.

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

Based on whether there is an entry in the Reset Point field, at runtime the Min Capture point is reset as follows:

When the trigger point is not defined
If	And	Then
An Initial Min Capture Value is	The Current value of the Expression is	The Min Capture point value is reset to the
Not defined	Unavailable	Initial value
Not defined	Available	Current value
Defined	Unavailable	Max possible value for the point type. E.g. for INT the value is +32767
Defined	Available	Whichever has the Min value
When the trigger point is defined
If		Then
An Initial Min Capture Value is		The Min Capture point value is reset to the
Not defined		Max possible value for the point type. E.g. for INT the value is +32767 for INT the value
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

When the value of the Min Capture point updates depends on whether or not you defined the trigger point as follows.

Trigger point	The Value of the Min Capture Point is Updated When the Value of the:
Defined	Trigger point is updated.
Not defined	Source point 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.

More information

Step 3.2. Configure virtual calculations.