Syntax

Point.OnChange

Description

To request the point's value on change. The next value of the point may be received by calling the GetNext method or function. The current value of the point is returned immediately. Any subsequent GetNext call will block until the point's value changes.

Only one of the OnChange, OnAlarm, OnTimed or OnAlarmAck requests may be activate at a time.

Example

Read the point value on change forever.

Sub main()

   Dim MyPoint as new Point    ' Declare the point object

   MyPoint.Id ="TANK_LEVEL"   ' Set the Id

   MyPoint.OnChange            ' Request the value on change

top :

   MyPoint. GetNext            ' Get the value

   Trace MyPoint.Value         ' trace it to the output window

   goto top                    ' repeat forever

end sub

See also

Point.GetNext (method); Point.OnTimed (method); Point.Cancel (method).

CIMPLICITY Extensions to Basic