An array tag in control logix has an index which tells you the position of an element in the array. Example: MyTag[2,4], in which MyTag is a 2-dimensional array tag, and MyTag[2,4] would be the 3rd element in one dimension and the 5th element in the other. The index ([2,4]), or posistion, can be a variable, or another tag, which can be changed in a sequenced if you wish. You can write logic wich will change the index of your array tag reference in an instruction, to operate on a different element of the array tag whenever you change its index. The sequencer instructions make this much easier to do in some cases.
Edit: A further example of sequencing the index of an array tag:
You can make two counters, in which the .ACC value of the counters are the indexes of an array tag. Example: MyTag[Counter1.ACC,Counter2.ACC]. As your counters increment, whatever instructions that operate on MyTag will operate on a different element of MyTag each time.
Another edit: If you want to be real specialized, you can create an array of custom data types for the acutal operations that you want to perform, then sequence through them. For example, if you had to identify a different communication path each time, and the communication path consisted of a string and some numbers, you could have an custom data type that represented the communication path, then make an array of these that represent all of your different possible paths that you want to use.
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