Real-Time VI palettes empty?

[johnsold]

We are completely new to LV Real-time programming. LV2015-32 bit on Windows (development system) and cRIO-9067 with assorted modules. MAX says the device is connected and running. It also says the Real-time software is installed.

We were following instructions in a Getting Started tutorial. (I am not at the development computer so I am not sure of the exact title). We reached the point where it told us to create a new VI from the RT project. It then called for a timed loop.  Neither the Functions palette on the BD nor the Controls palette in the FP contain anything.  It is rather difficult to create a VI with notcontrols, no BD structures, no functions and no subVIs.

We could drag things from an example program to the new VI and they are OK but we stiil can't get anything on the palettes.

Any clues as to what we missed?

Thanks,

Lynn

[AndyClegg]

Firstly, it seems a bit odd for me to give some pointers to somebody with your experience ... but here goes:

1. I assume you've got the LV RT module installed and licensed on the development computer.
2. I presume you're building a VI under the RT cRIO Target and not the cRIO's FPGA Target within the LV project ? VIs on the cRIOs FPGA will have some functions unavailable.
3. If you're just building a VI under cRIO RT then the same generic palletes as for standard LV programming should be available - with timed loop just under Programming | Structures | Timed Structures ? The "Real-Time" pallette contains things specific to a RT target.
4. I've not worked with the RT Linux cRIOs, but the older cRIOs I have used require them to have the core LV components installed when they are fresh out of the box. Also, the LV components on the cRIO must be compatible with the version of LV RT on the development system (see http://digital.ni.com/public.nsf/allkb/65840D61C75DFB7786257E2F006EFEB3). You can check what is installed on the cRIO through MAX (navigate to the cRIO, right click on Software, select Add/Remove Software - the first thing this does is show what is currently on the cRIO and their versions).
5. Doing a full restore of the core LV components on the cRIO isn't a big issue - and can sometimes fix things - just follow the steps for Add/Remove software above and continue, by selecting the currently installed software and click next to do a resinstall. On older systems, it only took 4-5 mins and seemed straightforward.
6. In your project, is the cRIO set to work in Scan Interface mode or FPGA ? In project cRIO Target  |  Chassis | right click Properties | Chassis configuration.
7. In project cRIO Target | properties - and see if there is anything that looks incorrect in there (you set scan engine timing in this window)
8. Once you do get programming the build specification for a RT target is a quite important to have right - again might be worth checking if there is one and if anything odd within it.

Most likely culprit is point 4! The last three shouldn't really affect what pallettes are available, but worth getting to know about when starting with cRIO.

Andy

[johnsold]

Andy,

Thank you for the detailed reply.  How would I ever learn anything if I only did the same things I already know?

1. Yes.

2. Yes.

3. This is where we first see a problem. Create a new VI from a LV cRIO RT project. All palettes are completely empty! The palette frame shows up but there is nothing in it. This occurs on both BD and FP.

4. This is the Linux RT.  MAX shows CompactRIO 15.0, some form of LV real-time and a bunch of other installed software, all current version.  {Your link to the KB article is broken because it captured the ")." at the end.}

5. Did this. No change.

6. I do not know how this is set up.  I will have my colleague check tomorrow. Which way should it be set?

7. Not sure if we even looked at that.

8. When we get there.

Lynn

[AndyClegg]

Sounds like a fairly fundamental problem if all palettes are affected. Are the palettes also empty if you have VI witin a regular LV project without any RT target ? It sounds like it isn't related to the RT target, but more to do with the development computer installation / licensing - but I would expect that is something you are super familiar with and have checked anything. Fundamentally with a RT target there shouldn't be any special trick / option needed to access these palettes - maybe that's all you need to hear to direct your troubleshooting back the installation on the development computer.

In LabVIEW under the Tools menu do you have Real-Time Module listed ? There should also be an FPGA Module as well.

I wonder if there is something in your development ssystem installation that is non-standard that you use for your general LV programming that is perhaps incompatible with RT? I've just looked through my vanilla installation of LV2015 and there isn't any specific setting/option that seems to be for enabling working with RT Targets.

Sorry that this isn't much help.

[johnsold]

Andy,

No. Any VI not in the RT project has the normal palettes. 

Not sure about the Tools menu.  I will have my colleague (who has access to the development computer) to check. I know he has gotten a fairly simple FPGA VI to run.  I think it is a fairly standard LV 2015 installation. LV 2012 is also on that computer.

Lynn

[johnsold]

My colleague thinks everything asked in points 6 and 7 above are OK.

The Real-time module is available under the Tools menu.

He opened a new VI and saved it under My Computer in the RT project and it has all the palettes.  He was able to get it to run and to make a temperature measurement. (One of the modules in the cRIO is a 9213 thermcouple device.) 

If the VI is under My Computer is it a Real-time VI? The VI with no palettes was created by popping up on the cRIO item in the project window and selecting New VI from the menu.

Lynn

[AndyClegg]

A VI under My Computer is running on your development computer. I guess the thermocouples plugged into the IO module on the CRIO are being accessible as networked shared variables, rather than something running on the cRIO. Though it at least shows something is working down there.

Is a VI running on your development computer "real-time"? That depends on timing in your application compared to determinism of timing on a PC - if you want to do something once every minute then you could regard it as real-time, but every 10msec definitely not. I guess you understand this kind of stuff from your normal LV programming. What is acceptable depends on what you are trying do.

For a VI to run on the cRIO it has to be under the cRIO item in the LV project. You can still run a VI interactively like you do when running a VI on a PC, but you also have additional options like deploy to chassis, run at startup etc - which is needed since you don't always want to just run an application instantly (e.g. if you want a headless system, where cRIO starts running a VI as soon as power connected without a development computer there).

I have no idea why you are not seeing the palettes for a VI under the cRIO - I wonder if it is a bug with that particular type of cRIO and version of LV, and perhaps should be something with the NI Support to deal with? I did create a LV project with a simulated CRIO of the type you have and with LV2015 which I am using the palettes are fine. See this screen grab:

[AndyClegg]

BTW  - the Compact RIO Developers Guide is really useful to explain some of the changes in programming needed for RT LabVIEW and how the cRIO architecture works (Scan Engine vs FPGA). I wish I had looked at it sooner on my first cRIO project.

http://www.ni.com/pdf/products/us/fullcriodevguide.pdf

[johnsold]

Andy,

That is what I suspected about the My Computer VI. The system will be running headless and without connection to the development computer part of the time (the most important part, of course).

The Developers Guide looks very helpful. I will dig into it on Tuesday.

I agree that it may be time to contact NI Support.

Thanks,

Lynn

[AndyClegg]

For developing a headless system - definitely read up about it, as there are quite a lot of subtle things. Here are a few things I learned:

• It took us a few attempts to get a deployment process that worked consistently, and once we had we didn't deviate from it to avoid creating an unexpected behaviour.
• If you have an FPGA application alongside your RT VI then there are a couple of ways that the FPGA can be deployed (manually, via build specification) or automatically by the RT VI itself.  http://www.ni.com/white-paper/9640/en/
• Check your cRIO CPU loading, if it is getting high (>80%) timing can become less deterministic
• Start-up - on power up your CRIO won't start running the application straightaway, so you have to be sure the system outputs start in a safe state before the 10secs or so it takes for the application to start running (the Linux cRIOs may be a lot better in this regard

Hope you get the Pallettes thing sorted. If you get any questions about headless then just ask.

Andy