After a loop completes a single iteration, sometimes you want to use the value of one of its calculations in the next loop
iteration. You can use a shift register to pass data from the most recent iteration to the next iteration.
What to Use
What to Do
Create the following diagram to pass data from the most recent loop iteration to the next iteration.
Customize the gray sections for your unique programming goals.
To share data with the next loop iteration, pass the data into a shift register on the right border of the loop. This right
shift register passes that data to a corresponding left shift register.
To create a pair of shift registers, right-click the loop border and select
Create Shift Register.
The left shift register contains data passed from the right shift register. Access this data by wiring the output of the left
shift register to the code inside the loop.
For the first loop iteration, an initialized shift register returns the value wired to its input.
If you do not initialize the shift register, it shares the data it held the last time the loop executed, even if that data
is from a previous execution of the VI containing the loop.
After the loop executes, access the data from the last iteration by wiring the output of the right shift register to the rest
of the program.
Only values from the last iteration exit the loop through the output of the right shift register.
In the previous example, the value the left shift register passes into the loop changes after each iteration. The following
table records the data each shift register contains after each loop iteration if the
initial value wired to the left shift register is 10 and the
loop count is 3.
||Value after First Iteration
||Value after Second Iteration
||Value after Third Iteration
|Left shift register
|Right shift register