Writes an element to an RT FIFO.


icon

Inputs/Outputs

  • cfiforn.png rt fifo —

    rt fifo is a reference to an existing RT FIFO.

  • cstr.png element —

    element is the data to write to the RT FIFO. This data type changes to match the type of the value you want to write.

  • ci32.png timeout in ms (0) —

    timeout in ms (0) specifies the time, in milliseconds, that the function waits for an empty slot to write the data in the RT FIFO. The default is 0, which returns immediately. A value of -1 waits indefinitely.

  • cerrcodeclst.png error in (no error) —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • cbool.png overwrite on timeout (T) —

    overwrite on timeout specifies whether to overwrite the oldest value in the RT FIFO if the FIFO does not have an available open slot and the value of the timeout in ms input expires. Use the timeout in ms input to specify an amount of time to wait for an open slot before overwriting the oldest value. If the value of the timeout in ms input expires and the overwrite on timeout input equals TRUE, the RT FIFO overwrites the oldest value and returns TRUE in the timed out? output.

  • ififorn.png rt fifo out —

    rt fifo out is a reference to an existing RT FIFO.

  • ibool.png timed out? —

    timed out? returns TRUE if the timeout value has expired before an empty slot becomes available in the RT FIFO for the write operation.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.

  • iu32.png # elements —

    # elements returns the number of elements remaining in the RT FIFO after the read or write operation.

    • If the RT FIFO does not have empty elements, this function waits for an amount of time equal to the value of timeout in ms for an element to become available. If an empty element does not become available before the value of timeout is ms expires and the overwrite on timeout input is TRUE, this function overwrites the oldest element in the RT FIFO and returns TRUE in the timed out? output.

    Note If you use a Real-Time FIFO to transfer waveform data, the variant element of the waveform does not transfer because variants are variable-sized and therefore incompatible with the Real-Time FIFO.

    Examples

    Refer to the following example files included with LabVIEW Real-Time Module.

    • examples\Real-Time Module\RT Communication\RT FIFO\RT FIFO Communication.lvproj