Cannot synchronize to scan engine

[tk4b]

Hi I've got a cRIO-9073 that I'm trying to work with and can't get a VI to synchronize to the scan engine.  I'm alright with LabView in general, but pretty new to cRIO, Real Time, etc.  Basically the problem is that when I set up a timed loop in a VI on the target and double click to configure the timed loop, I should just be able to set te timing source as "Synchronize to Scan Engine" but that option is greyed out.  Any idea what I can do about this?  I can't find info anywhere telling me why this is greyed out or what to do about it.  The cRIO seems to be set up just fine otherwise, and I can read an analog voltage off one of the modules.  Using LabView 2010 btw (and not using FPGA).

[Zachmx]

Do you have NI Scan Engine installed on the cRIO?

You can do this in MAX by expanding the cRIO under Remote Systems, right-clicking on the Software tab, and selecting Add/Remove Software. 

In this window, select your NI-RIO version (should say "Already Installed") and click Next. NI Scan Engine should be an option in the next window. Check the box and finish the installation wizard.

[tk4b]

Hi Zach, thanks for your reply.  Yes I already have NI Scan Engine 2.0 installed on the cRIO.

[Zachmx]

Are you sure this VI is under the target in the Project Explorer? The window you see appears when I create a VI under My Computer.

[tk4b]

Yes, the VI is on the target ("read voltage.vi"):

I am thinking that some part of the problem may have to do with the fact the the cRIO says "Real-Time features not available."  This is despite the fact that I have Real-Time installed on the cRIO:

Any thoughts?

[Zachmx]

I think you are right, can you try reinstalling the Real-Time Module for LabVIEW? You should be able to see the Real-Time module listed in the tree under LabVIEW 2010.

Order of installation is important here, you need to make sure you install Real-Time for the correct LabVIEW version and then install a compatible NI-RIO version.

If that does not work, you can try to push software to the cRIO again. If you still see the message "Real-Time features not available", you may want to upgrade your NI-RIO driver to 3.5.1

https://www.ni.com/en/support/downloads/drivers/download.ni-rio--legacy-.html#326641

[tk4b]

I went ahead and did a fresh install of LabView 2011, including all components that should be needed for this.  It looks like there must have been something missing or wrong with my old LabView 2010 installion, because now it appears to work and I can synchronize to the scan engine.

However now I have a whole new set of issues -- I am getting weird aliasing of the signal I'm trying to read, which maybe has to do not with the sampling rate of the cRIO, but rather the rate at which it is able to publish the data back to the host computer (???).  I read something saying transfer rates can be a lot faster using FPGA, FIFO and DMA, but that is a whole new beast that I know very little about.  Any links to beginner signal acquisition with scan mode interface would be great.  Also I'd like to hear any input as to why this signal aliasing might be happening.  Thanks!

[Zachmx]

I'm glad you were able to get scan mode working!

I would suggest starting a new thread for your acquisition question, as it will likely be missed in this thread.

Scan mode uses a fixed FPGA personality to acquire data from the hardware. Programming in FPGA mode will allow you to customize how you I/O works and how fast it transfers to the Real-Time side of the cRIO, but the network communication speed will be the same for both. For getting started guides, you can check out the links below. Good luck!

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000x2HMCAY&l=en-U (Scan mode tutorial)

https://www.ni.com/docs/en-US/bundle/labview-real-time-module/page/rt-best-practices-portal.html (RT Best Practices Portal)

https://www.ni.com/en/shop/electronic-test-instrumentation/add-ons-for-electronic-test-and-instrumen... (Intro to FPGA)