csmstr - Omega Engineering

CONFIGURING DATA TAGS
EDITING FLAG TAGS
• The Elements property is used to indicate how many data items the array should
hold. Array elements are referred to using square brackets, such that Array[0] is
the first element, and Array[n-1] is the last element, where n is equal to the
value entered for this property.
• The Access and Storage properties are as described for flag variables.
• The Simulation property is as described for flag variables. Note that the value to
be simulated applies to all elements of the array. If you need to simulate on a per
element basis, use a number of formulae to alias the array elements.
• The Read Policy property is used to define how Crimson will read the data for
arrays that are mapped to remote data items. The table below lists the various
policies that can be configured, and describes their operation…
MODE
Read Adaptively
Read Manually
Read Whole Array
DESCRIPTION
Any referenced array elements will be added to the
communications scan. Data either side of a referenced
element, as defined by the Read Ahead and Read Behind
properties, will be read as well. Old data may be
displayed momentarily when an element from an adaptive
array is first displayed on the virtual HMI.
The array will be read if and only if the ReadData
function is called. This mode is useful for items that are
read only rarely, or which are known not to change in the
remote device.
The entire array will be added to the communications
scan if any element in the array is referenced. This mode
ensures that all data items are available before they are
referenced, but can lower system performance.
• The Read Ahead and Read Behind properties modify the behavior of the adaptive
read policy by controlling how many adjoining registers will be read when a
specific array element is referenced. The adjoining reads are used to maximize
the chance of data being available when indirection is used to scroll up or down
an array. The default values should be suitable for most applications.
• The On Write property is as described for flag variables.
REVISION 6 PAGE 111