You are here: NI Home > Support > Product Reference > Manuals > LabVIEW Real-Time Module 8.5 Help

Controls and indicators can affect the determinism of a deterministic VI. Use the RT Communication Wizard to share control and indicator data from a deterministic VI using deterministic methods. Select Tools»Real-Time Module»Communication Wizard to open the RT Communication Wizard. The RT Communication Wizard creates a new deterministic VI that uses shared variables or Real-Time FIFO VIs with remote communication methods to share data with a VI running on the host computer.

Shared Variable Method—The RT Communication Wizard creates a new deterministic VI, a host VI, and project and library files that define the shared variables. The new deterministic VI uses shared variables to share control and indicator data with the host VI without affecting the determinism of the deterministic VI.

Remote Communication Method—The RT Communication Wizard creates a new deterministic VI and a normal priority VI that run on the RT target and a host VI that runs on the host computer. Real-Time FIFO VIs share data deterministically between the deterministic VI and the normal priority VI on the RT target and do not affect the determinism of the deterministic VI. The normal priority VI then shares data with the host VI using the remote communication method that you select.

You can select from the following front panel communication methods:

• Shared Variables—Shared variables with a real-time FIFO that transfer data out of a VI without affecting the determinism of the VI.
• TCP—TCP is an industry-standard network communication protocol that is connection-based. TCP is a good protocol to use when transferring large amounts of data between systems because it is fast and lossless.
• UDP—UDP is an industry-standard network communication protocol. UDP is a faster communication protocol than TCP, but it is not connection-based, so you cannot verify the arrival of data and data can be lost.
• Logos (FieldPoint Only)—Logos is a network communication protocol developed by National Instruments based on industry-standard UDP for traditional FieldPoint and Compact FieldPoint Ethernet modules. Ethernet FieldPoint modules have an embedded Logos Server which enables reads and writes to the physical I/O modules on the FieldPoint bank from a remote system. Unlike UDP, Logos performs verification of data arrival to ensure lossless data transfer.

The RT Communication Wizard generates the following files:

• deterministic VI—Runs on the RT target and contains the deterministic tasks and Real-Time FIFO VIs to transfer front panel data deterministically to the normal priority VI.
• Normal Priority VI—If you select a remote communication method, the normal priority VI runs on the RT target and contains all non-deterministic network communication tasks to update the host VI with front panel data received from the deterministic VI.
• Host VI—Runs on the host computer and displays the front panel controls and indicators of the deterministic VI.
• LV Project—If you select the shared variables method, the RT Communication Wizard creates a LabVIEW project file that defines the shared variables.
• Project Library—If you select the shared variables method, the RT Communication Wizard creates a project library containing shared variables for the project.

My Profile | Privacy | Legal | Contact NI   © 2009 National Instruments Corporation. All rights reserved.   |