Real-Time FIFO Page (RT Module)
From the Project Explorer window, right-click an RT target or project library under a target and select New»Variable from the shortcut menu, or right-click an existing shared variable and select Properties from the shortcut menu to display the Shared Variable Properties dialog box and this page.
Use this page to enable and configure the real-time FIFO of a shared variable. This page includes the following components:
- Enable Real-Time FIFO—Enables the real-time FIFO for a shared variable of type single-process or network-published. If you configure a network-published shared variable with network buffering and you enable the Real-Time FIFO, the network buffer must be as large as one FIFO element to ensure that data can be written. If the network buffer is smaller than a FIFO element, the network buffer overflows and no data transmits over the network.
Note RTX When you enable the Real-Time FIFO for a single-process shared variable and also place a check in the Enable timestamp checkbox on the Variable page, the read node always returns a timestamp of 0 because recording the timestamp causes jitter. - Single Element—Specifies a FIFO buffer with a single element. If you select an array or waveform data type, you must specify the size for the array elements or the size of the waveform.
- Multi-element—Specifies a FIFO buffer with multiple elements. You can configure the size and the elements of the FIFO buffer to match the settings from the Use Buffering section of the Variable page or you can configure a custom size for the FIFO and the FIFO elements.
- Use network buffer configuration—Uses the configuration specified in the Use Buffering section of the Variable page to configure the size and elements of the FIFO.
- Custom—Uses a custom configuration for the size and elements of the FIFO. You can specify the size of the FIFO buffer and the size of the elements in the FIFO. If you select an array or waveform data type, you can specify the size for the array elements or the size of the waveform.