Scan Engine & EtherCAT Custom Device Feedback

[StephenB]

ah... great. making progress.

It is likely running out CPU so it is dropping network communications and focusing on real-time tasks. Try 100 Hz and I bet it will work. Also check the "sync nivs to scan engine" check box on the custom device page to get a little more performance on cRIO.

After you finally get a successful deploy, check all the "count" channels under system channels to make sure you're not getting late counts. same goes for the count channel under the status of the custom device.

The 9022 running NI VeriStand usually maxes out around 500 Hz. Depending on how many IO points and models you are running, it could run out of CPU far before then. Do you know the rate your application needs to run at? Can you tell me more about your application?

If you need to run faster I recommend PXI controllers. They are much faster. If you must have the cRIO form factor consider the 9082 or 9081 which are much faster than the 902x cRIOs.

[Will_T1]

Right again. It works at 100Hz and doesn't fail out. The counts are at zero when I put the indicator called "medium" on them. I assume this is good, although I didn't actually read what they are counting. (Lost Packets?)

The application is a wind turbine controller, with full state logic, yaw and blade pitch control, as well as some data logging. The control loops for yaw and balde pitch don't need to be faster than 100Hz, but PWM signals for control signals may need to be faster. In fact, some of those control loops can probably run on the order of 5Hz. This is one big model designed in Simulink, built to a VxWorks .out file, although if it is adviseable, I can break the state logic, yaw and blade pitch control into separate models.

There is also some fault testing and safety loops in the control. Do you think those may be best added as FPGA tasks or LabVIEW custom devices, rather than running in the Simulink portion? If so, do you think they will 'play nice' with Simulink models?

[Aaron_Smith]

We have observed a couple of  issues with channels set up on digital modules in a cRIO chassis (9118) and the Scan Engine & EtherCAT Custom Device for VeriStand 2012.  We have a 9411 set up with the PWM Specialty Mode to measure a speed signal.  We have also created a calculated channels based on one of those channels to display power.  What we noticed is that if we click on or expand the module channel list in the system definition, it breaks the calucated channel link. 

Also it appears that you can only have two digital modules set up in specialty mode at one time with our cRIO.  We had 9411, 9474, and 9475 modules installed and each set up in a specialty mode.  During deployment, we received error -65407: In Scan Interface mode, you can configure only two slots for specialty digital I/O. If you want more specialty digital slots, add an FPGA target under the chassis to put the chassis in LabVIEW FPGA interface mode.  This isn't a problem for our application, but I hadn't seen that limitation in the literature before so we wanted to mention it. 

[StephenB]

Hey Aaron,

Thanks for the feedback. I can confirm the first issue as a bug and I will note it in the known issues list until I get a chance to fix it.

For the second item. I agree, we could make this more clear. There is a workaround though if you have LabVIEW FPGA and using version 3.5 or later of this add on. you can create a project with several (2+) digital modules configured for specialty digital mode under the chassis and a blank VI under the "FPGA target". Then compile the blank VI and import the compiled bitfile into NIVS under the "user variables" section of the local chassis. That bitfile will contain as many slots enabled for speciality digital (as well as reuglar scan) as you configured digital modules in the project.

[Devin_K]

Just to add on to what Stephen said, you can read more about this limitation in the scan interface documentation.

[StephenB]

Aaron, I just posted a fix for the channel linking issue

[joshe]

Hi,

I am seeing a posible bug with my setup.  I have running a PXI system (8110) with 2 ethercat masters and 3 slaves on each.  I am using version 3.4 of the addon.   I have 9219's that are configured for PT100, the are bouncing from there max high to there max low value.  When I set up the system with 1 master and 6 slaves the 9219's work fine.  I was using 2 masters to solve some performance issues, so I would like to be able to use that configuration.  Would the newer version of the addon fix this?  Is there a workaround for using 2 masters?

Please help!

Thanks!!!

[StephenB]

Hi Joshe,

Sorry to hear about this. I haven't seen this behavior before. Can you take a look at something to help me narrow down the issue?

If you open the Distributed Systems Manager (Start Menu -> National Instruments) and browse to your target (you may have to right click my systems and add it manually), do you also see the bad values there?

If you only see bad values in NI VeriStand, perhaps you can upgrade to the latest version of the add on. We cleaned up a few loose ends. The upgrade is painless, just download the latest version and replace your "Scan Engine" directory inside the custom devices directory with the download, then open and resave your system definition file(s).

[joshe]

Hi Stephen,

I did upgrade over the weekend and saw the same issue.  Is there anything else I can do to help you diagnose this?  It would be very handy to have this fixed.

[Devin_K]

Did you follow Stephen's suggestion about looking at the values in Distributed Systems Manager?  What were the results?  This would help us understand if it's a problem with the drivers or the custom device.