Passing An Array Through An RT FIFO Only Outputs One Element In The Array

Updated Apr 3, 2018

Reported In

Software

  • LabVIEW

Issue Details

I am writing an array of data into an RT FIFO but when I read from that RT FIFO I only read an array with one element in it.  

Solution

When creating the RT FIFO and defining the FIFO size you must not only specify the number of elements in the FIFO (the number of arrays that can be in the FIFO) but also define how many elements are going to be in the arrays themselves.  This is by default 1, so change this to a suitable size for your application.

Additional Information

Due to the determinism that comes with using RT FIFOs you must know the size of memory that you need in order to use them.  Regular FIFOs can allocate memory dynamically which make them easier to work with, but non-deterministic in nature.

Related Links

Getting Started with CompactRIO - Performing Basic Control with Real-Time Scan Mode

Real-Time FIFO Frequently Asked Questions

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