Chapter 4. Ladder Diagram (LD) Programming
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PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual
GFK-2950C
Example - FOR_LOOP that Iterates Through Dimension 1 of an Array
To use a FOR_LOOP to access array elements by means of a variable index, you must ensure that the
FOR_LOOP does not iterate beyond the last element of the array.
In the following logic, MOVE_DINT initializes the variable D1_temp to 0. ARRAY_SIZE_DIM1 counts
the number of elements of a one-dimensional array named D1_Array and outputs the result to
output Q. Because the index of the first element of an array is zero, the loop must iterate (Q - 1)
times. SUB_DINT performs the subtraction and the result is converted to an INT value and assigned
to variable D1_size.
In the following rungs, the FOR_LOOP executes when D1ON is set to On. The variable index D1_Index
increments by 1 from 0 through D1_size, the value calculated by ARRAY_SIZE_DIM1 and SUB_DINT. In
each loop, the value of D1_temp is assigned to the element D1_Array[D1_Index] and D1_temp is
increased by 1.
You can use a FOR_LOOP to iterate through an array’s second dimension in a method similar to this
example. You can also use nested FOR_LOOPs to ensure that operations on elements using two
variable indexes each do not exceed their array dimension. For additional examples, refer to the
online help.
Summary of Contents for PACSystems RX7i
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