Porting LV8.0 code to LV Real Time

[MogaRaghu]

I have an application where I am using PCI-6229 hardware with LV8.0 code. Using a 50mS Timed Loop to control all machine function including the On/Off of a solenoid valve at about 200mS intervals. ( On for 200mS and Off for 200mS )

As could be expected the on/off timings are never accurate and at times vary quite badly when the CPU is busy with some background acts. ( The OS is Win-XP Pro. )

I would like to put up a proposal to the client to port the existing code to LV Real Time to make the solenoid switching more deterministic.

Have been spending lots time on  the NI site reading about LVRT. Its a major topic and the learning curve is not very steep...  And I need to immediately put forward a clear technical proposal to the client and do not have the time to go through the tutorials in detail for that. Can someone outline the process of migrating to Real Time including the recommended hardware change ? ( Presently almost all of the DIOs and AIOs of the 6229 are used up and I have LV8.0 Full development package)

Thanks

Raghunathan

[Brian_K.]

Hi Raghunathan,

Your question is a good one.  I will first outline what my assumptions are:

1)  By port over, you mean you want to migrate from a Windows based LabVIEW program (non-deterministic) to a Real-time operating system based LabVIEW program (deterministic).

2)  The operations in your current program have the possibility of being deterministic.  Let me expand.  Some operations will never be deterministic.  For example currently TCP communication is non-deterministic, the hand-shaking involved makes for timing hold ups.  You can do TCP communication but it must not be in the time critical portion of your code.

If both above are true then the process is very straight forward.

1)  Get a supported real-time target.  That is some peice of hardware that runs a real-time operating system.  Since you are using the PCI-6229 I think a desktop computer formatted and installed with the ETS operating system would be good.  Here is a link for how to tell if the desktop is ETS compatible:

http://forums.ni.com/ni/board/message?board.id=170&message.id=241702

2)  Include the target into your project explorer and set it up to your needs.  Since 8.0 the project explorer is the best way to organize your overall goal.  By included your target you can now see what VIs will run on your host (Windows desktop), and what will run on your target (hardware that runs the real-time operating system).

3)  Drag the VIs that were on your host (non-deterministic) to your target (deterministic).  This makes it so that when you run you VI it will run on the target and thus a real-time operating system.  The idea is to make the conversion as transparent as possible.

I hope that answers your questions.