Summary, Tips, and Tricks on Repetition and Loops **new** 2004/06/18 11:26:34.661 GMT-5 2004/06/18 11:27:09.336 GMT-5 National Instruments certification@ni.com Harika Basana ilsai@rice.edu Elizabeth Gregory lizzardg@rice.edu Malan Shiralkar mshiralkar05@hotmail.com National Instruments certification@ni.com Use structures on the block diagram to repeat blocks of code and to execute code conditionally or in a specific order. The While Loop executes the subdiagram until the conditional terminal receives a specific Boolean value. By default, the While Loop executes its subdiagram until the conditional terminal receives a True value. The For Loop executes a subdiagram a set number of times. You create loops by using the cursor to drag a selection rectangle around the section of the block diagram you want to repeat or by dragging and dropping block diagram objects inside the loop. The Wait Until Next ms Multiple function makes sure that each iteration occurs at certain intervals. Use this function to add timing to loops. The Wait (ms) function waits a set amount of time. Coercion dots appear where LabVIEW coerces a numeric representation of one terminal to match the numeric representation of another terminal. Use shift registers on For Loops and While Loops to transfer values from one loop iteration to the next. Create a shift register by right-clicking the left or right border of a loop and selecting Add Shift Register from the shortcut menu. To configure a shift register to carry over values to the next iteration, right-click the left terminal and select Add Element from the shortcut menu. The Feedback Node stores data when the loop completes an iteration, sends that value to the next iteration of the loop, and transfers any data type. Use the Feedback Node to avoid unnecessarily long wires.