Transfer Array Data to a SystemLink™ WebVI

Updated Feb 15, 2022

Reported In

Software

  • LabVIEW NXG
  • LabVIEW NXG Web Module
  • SystemLink Cloud

Issue Details

  • How can I transfer an array of data to a WebVI using SystemLink™ functions?
  • The SystemLink™ Write Node won't accept an array input. How can I write an array to the WebVI?
  • Is there a SystemLink™ function that accepts array data as an input?
  • I'm using LabVIEW NXG or G Web Development Software to publish a WebVI to SystemLink™ Cloud. Is there a way to send array data between the VIs?
 

Solution

The SystemLink™ Write and Read Tags do not accept arrays as a valid input. Only single elements can be accepted.
Arrays can be transferred to a WebVI by indexing the array and writing a single element at a time.


Writing Arrays

In order to write an array of data, each element should be written one at a time by indexing the array in a While Loop.

In the below snippet, the array element is incremented for each iteration of the loop.

This snippet can be used as a SubVI that is called in a For Loop to Write a single element per iteration. The attached ZIP file contains an example of this.
 

This image is a LabVIEW NXG snippet, which includes LabVIEW code that you can reuse in your project. To use a snippet, right-click the image, save it to your computer, and drag the file onto your LabVIEW NXG diagram.


Reading Arrays

To read the array data in the WebVI, a Read Tag can be wired directly to the Open Tag. This is shown in the below snippet.