How does downloading of a particular VI to the RT Engine work?

[TobyRT]

Hi,

I'm working with LabViewRT and the PCI7030/6040E DAQ board.
I would like to know how exactly downloading of a VI to the RT Engine works.
A copy of my VI on the host system is transferred to the RT Engine and after that the VI on the RT Engine is totally independent from the VI on the host system, am I right?

Thanks for your help.
Tobi

[JR_A.]

For the most part you are correct. When you are targeted to an RT system and you download a VI (either by pressing the run button or selecting Download Application from the Operate menu) the VI is transferred to the memory on the RT engine. Actually, it can be thought of as just the block diagram being transferred because the front panel is not used on the RT system. However, being 'totally' independent would depend on if you were in development mode or deployed. In development mode, you have LabVIEW RT targeted to the RT device and you can see the front panel of the VI running on the RT engine. The communication to the front panel on the host is done for you automatically in a normal priority thread. It is considered deployed, when you run the VI on the RT engi
ne and then use a different VI to communicate to it through some means of communication such as TCP, VI Server, or Shared memory in the case of a 7030.
The 7030 is independent in the sense that once code is downloaded and run, it will continue to run as long as the PCI bus is powered. That means you could download and run code on the 7030, and then crash Windows and the code on the 7030 would continue to run as long as the board was powered.

Regards,

JR A.
Application Engineer
National Instruments

[TobyRT]

Thanks for your answer.

Are there any examples where a different VI communicates with the VI on the RT Engine via shared memory?

My problem is if I use the automatic communication to the front panel on the host PC my control circuit becomes non deterministic.

[JR_A.]

There are examples using shared memory that ship with the LabVIEW RT module. They can be found by selecting "Find Examples" from the Help menu and then looking in the Toolsets and Modules>>Real-Time folder. Some of the examples will work on all of the RT targets and some of them are specific to the 7030 and use shared memory. The examples show how to the shared memory features but are not necessarily architectured the way you will want to make your VI's. You will probably want to have two subVI's running on the RT engine with one being in the Time Critical priority and one being in the Normal priority and communication between them.

Regards,

JR A.
Application Engineer
National Instruments

[TobyRT]

I'm working with LabViewRT 5.1.2 and I can't find these examples.
Would you mind sending me some examples on my e-mail adress. (iwib78@yahoo.de)
Thanks

Regards,

Toby

[JR_A.]

The examples in LabVIEW RT 5.1.2 can be found in the ..\LabVIEW\Examples\RT folder.

Regards,

JR A.
Application Engineering
National Instruments