1. CS320n –Visual Programming
Arrays

2. What We Will Do Today
Learn about arrays and how to work with them in LabVIEW
Visual Programming
Arrays in LabVIEW

3. What are Arrays? An array is like a list
Up until now in LabVIEW we have dealt with scalars, variables with a single value
An array is a collection of elements
all elements in the array have the same data type: boolean, double, int, String
Visual Programming
Arrays in LabVIEW

4. Thinking About Arrays Array elements are accessed by their index
Indices start at 0, not 1
This is a one dimensional array
arrays can have more dimensions
2 dimensional array, like a table of data
Visual Programming
Arrays in LabVIEW

5. Arrays in LabVIEW Arrays can be created on the block diagram
on block diagram select arrays sub palette
select array constant and drag onto block diagram
this creates an array shell
Visual Programming
Arrays in LabVIEW

6. Creating an Array on Block Diagram
array shell
to finish creating the array the data type the array holds must be determined
drag a constant from a sub palette into the elements portion
this determines the data type of the array
index elements
after dragging numeric constant
into elements
Visual Programming
Arrays in LabVIEW

7. Array Constants on Block Diagram
type the initial value into the element section
the array can be expanded up and down or left and right to view other elements
click and drag to expand array to view more elements
element 0 set to 12
Visual Programming
Arrays in LabVIEW

8. Array Constants on Block Diagram
Array expanded to show elements 0 through 10
Clicking on index array display other elements. The element on the far left (or
top) of the array has the index shown in the index box.
Light blue elements are elements that have not been initialized.
Visual Programming
Arrays in LabVIEW

9. Creating Arrays Via the Front Panel
Arrays can also be created via the front panel
click on the Array and Cluster sub palette
click and drag an array to the front panel
this creates an array control shell
Visual Programming
Arrays in LabVIEW

10. Creating Arrays Via the Front Panel
a data type must be added to the array shell
drag a control or indicator of the data type you want into the shell
can change from double to int by right clicking on elements and selecting “data range”
click on icon under “representation” and change to an integer type
array shell
Visual Programming
Arrays in LabVIEW

11. Arrays on the Front Panel
Control can be expanded to show more elements of the array
grey elements indicate uninitialized values
the size (or length) of the array above is 1
if other elements are given values, the array size automatically expands
Visual Programming
Arrays in LabVIEW

12. Auto indexing
LabVIEW has a feature with loops and arrays called auto indexing
If you wish to carry out an operation on every element of an array a loop is required
assume we have an array and we want to double every element
Visual Programming
Arrays in LabVIEW

13. Using Auto indexing array indicator Visual Programming
Arrays in LabVIEW

14. Notes on Previous slide
no value wired to count terminal
count based on length of array
thick wire going in and coming out, but thin inside the loop
working with a single element of the array
must create array indicator to show array when finished
can be a bit tricky
Visual Programming
Arrays in LabVIEW

15. Manipulating Arrays Many functions for working with arrays
initialize array
initial value for all elements
size of the array
Visual Programming
Arrays in LabVIEW

16. Getting the Length of an Array
output is size
of array
array input
Visual Programming
Arrays in LabVIEW

17. Changing Values of Elements
Giving an array, set the value at position 2 (actually the 3rd element of the array) to 1 more than its previous value
Uses Index Array and Replace Array Subset
value at element
resulting array
array
array
index
new value for element
Index Array
index
Replace Array Subset
Visual Programming
Arrays in LabVIEW

18. Completed Diagram Index Array (access element)
Replace Array Subset (Change value of 1 element)
Visual Programming
Arrays in LabVIEW

19. Class work
Download the ArrayExercise.vi program from the class web site.
The program creates an array of size The elements of the array are random values from 1 to 100
Add 1 to all elements that are odd.
Use a case statement or select function inside the loop to increment the array element if R is equal to 1
Visual Programming
Arrays in LabVIEW