Using rtx target with vision application

[simonerom]

Hi,
I need to do a fast vision inspection (about 40 frames acquired and ispected per second)
so I was thinking to a Desktop PC as a realtime target. Provided that I need hi level features
(like show the current inspected image, or do usb image backups, have an operator interface,
etc...), I thik that an RTX target based on a P4 or Dual Core would be the best choice.

So the question: is it possible to realize a vision application using an RTX target? This application
should communicate the result of the inspection to the plc every 400ms (during which it ispects 40
frames of a rotating part) or, at least, I need that the vision application is the highest priority task on the PC.

Thanks,

Simone.

[ThSa]

Simone,
unfortunately IMAQ devices are not supported on RTX targets.
I think we have to clarify some things before you get a hint which could be a possible system for you...

You have two opportunities to reach your aim:
-> RT Desktop PC with ETS with some restrictions or
-> PXI System with the full functionality

The restrictions for the Desktop PC system might be:
-> To find a supported desktop PC
    Remedy:     a) Use the following tool to validate the Desktop PC (try and error):
                        b) Contact "Hematec". They have experience with our RT-OS
-> It is not possible to show the image on a monitor which might be connected to the RT Desktop PC (IMAQ WindDraw - Window Number 15)
    Remedy: Use a PXI system

All other functionality is given and furthermore it is possible to save pictures via 1394 or USB to an external harddisk.

Hope this helps,
ThSa

[simonerom]

Why this is possible with the pxi?
Isn't, for example, the PXI-8105 a standard Intel/Windows architecture?
Why you can get the [real time + labview + vision libs + winXp] work on this PXI
and not on a Desktop PC? Is the real time kernel  used on the WinXP/PXI system
different from the RTX used on common PCs?

Bye,

Simone.

[ThSa]

Simone,
it is possible to run the Vision Development Module on a Desktop PC with ETS.
I never tried to run only the Vision Development Module on a Desktop PC with RTX, but it is definitely impossible to run NI IMAQ or IMAQdx on a Desktop PC with RTX.
The reason is that the Ardence OS needs appropriate programmed dlls...

The display for the images might work with the newest IMAQ driver but I never tried it.
The other possiblity is to use the IMAQ RT Video Out.vi

ThSa

[BruceAmmons]

Do you really need Realtime?  This won't make your processing any faster.  It will only make it deterministic.  You might be better off just using a very fast computer and buffered image acquisition.  If Windows slows you down, you can catch up fairly quickly.

If your processing is going to take so much time that you can't deal with the Windows overhead, your best option would be converting a fast PC to ETS.  You could use an average speed PC for your Windows user interface.

Bruce

[JohannS]

In general I agree with Bruce. The strongest benefit of running LabVIEW RT, compared to Windows, on a Desktop PC is the determinism of the system. If you prototype your acquisition and processing to be 330 ms (for example), then each subsequent iteration should take exactly the same time. With Windows you may lose your determinism and some background tasks (scanning for virus, checking for OS updates, etc) can seriously affect your loop times, especially when disk and network I/O is involved.

With the latest LabVIEW RT you have support for external FireWire and USB drives. With the appropriate Intel graphics adapter (as found on some PXI and desktop PCs), you can also connect a monitor directly to the system for video display.

Johann

[simonerom]

I think you're both right: maybe a dual core based industrial pc, with all unused services disabled and the VBAI process boosted to the maximum priority will do the job.
This because it isn't an hard real time application (not a problem if 2-3 parts over 1000 will fail the inspection because of the system latency), so for now, this will be my solution.
Anyway, I'd be more calm if I knew that nothing could slow down the inspection process, also if it has to occur every 150ms instead of 1-2ms, so I'll continue finding a real-time/user friendly solution.

By know I have an i845 chipset, but I miss the right ethernet card to build an ets target. Maybe I found an Intel Pro 100 s on ebay, but maybe some one knows any other commercial ethernet card that hosts the required chipsets (Intel 82540, 82550, 82558, 82559, Broadcom 5751)?

Just another question:
what does will be displayed on the ETS target running a vbai inspection? Nothing? If I add an operator interface to the main panel with labview, will it be displayed, or I have to use a remote pc to see something?
 

Tanks for your answers.

Simone.

Message Edited by simonerom on 12-11-2006 04:30 PM

[BruceAmmons]

Be careful.  I don't think dual core processors are compatible with ETS.  Make sure you read the rules for selecting an ETS computer.  The dual core machine would probably work well as a Windows machine for doing the processing, though.  It would probably end up being faster than any RT machine you could make.

I found an Intel Pro/100 S for about $20 at www.compuvest.com.  I never purchased one, but I am pretty sure it would work in an ETS computer.  This is much easier than trying to find a motherboard that has the proper built in NIC.

Bruce

[ThSa]

If you want to use a dual core as RT Desktop PC (ETS) you have to disable one core.

BR,
ThSa