What happends when I read a global fifo variabel that is empty

[ollesvensson]

The fifo in labview realtime has outputs that indicates different states of the fifo but the global fifo that can be used to communicate whith real time controller, fpga and host computer has nothing. How do the host computer know that it has read all information and the fifo is empty.

[Jimmie_A.]

Hello!

Please check the following link:

http://zone.ni.com/devzone/conceptd.nsf/webmain/5B4C3CC1B2AD10BA862570F2007569EF

Quote:

"By enabling the real-time FIFO, you can select between two slightly different types of FIFO-enabled variables: the single-element and the multielement buffer. One distinction between these two types of buffers is that the single-element FIFO does not report warnings on overflow or underflow conditions. A second distinction is the value that LabVIEW returns when multiple readers read an empty buffer. Multiple readers of the single-element FIFO receive the same value, and the single-element FIFO returns the same value until a writer writes to that variable again. Multiple readers of an empty multielement FIFO each get the last value that they read from the buffer or the default value for the data type of the variable if they have not read from the variable before."