4.8.57         .SIZE

Array Size. Most devices and communications protocols do not support arrays. Used in IO Tags if IO device supports arrays.  Refer to your Device Manufacturer's manual and the specific device driver guide.

Constant Tags and Local Screen Tags can be defined as arrays, where one tag can specify an array of values, each element accessed using tag(number).   

Range:                    1 to 99
Field Type:            analog 
Tag field:               .SIZE

Try using a Block if you need an array-like feature for IO tags read from your device.

An array is commonly used by programmers in looping programs or indexed calls.  Constant Tag arrays allow users to reference a global tag using the array convention tagname(index) in scripts or programs.

For example, if arraytag is an array type analog constant point of array size 20 (i.e. 20 elements) the following script will set all the values to 0. 

for {set  x  0} {$x<20} {incr x} {

SETVAL "arraytag($x) = 0"

            }