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of an array must be of the same data type (e.g., BOOL, SINT, or INT). An array occupies a contiguous block of controller memory. Arrays are similar to tables of values. The use of arrayed data types offers the fastest data throughput (output) from a ControlLogix processor. Because arrays are numerically sequenced tags of the same data type that occupy a contiguous memory location, large amounts of data can be retrieved efficiently. Arrays can be built using 1, 2 or 3 dimensions, as illustrated in Figure 15-24, to represent the data they are intended to contain. A single tag within the array is one element. The element may be a basic data type or a structure. The elements start with 0 and extend to the number of elements minus 1. Figure 15-25 is an example of the memory Array - Temp Data Type - INT5 Temp0 297 Temp1 200 Temp2 180 Temp3 120 Temp4 100 Figure 15-25  Memory layout for a one-dimensional array. layout for a 1-dimensional (one column of values) array created to hold five temperatures. The tag name is Temp and the array consists of 5 elements numbered 0 through 4. Memory and Project Organization  Part 1 343


Petruzella_ProgrammableLogicControllers__5e
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