topic Re: cRIO Waveform Reference Application: Potential Frimware Bug with External USB Drives in Components

CompactRIO Waveform Library

ninjaphil — Fri, 05 Aug 2016 19:10:10 GMT

Please provide feedback, comments and questions on the NI CompactRIO Waveform Library in this thread.

Re: cRIO Waveform Reference Application

Jeff_T. — Fri, 24 Jul 2009 14:59:03 GMT

Hello everyone! I am very excited about this component and would love to hear about your experiences, ideas, pain points, etc. I will be monitoring this forum regularly; any feedback is both welcome and appreciated. I have already gotten some good ideas from customers and I plan to release a new version sometime in the fall of 2009.

Jeff Tipps

Systems Engineer - Sound and Vibration

Re: cRIO Waveform Reference Application

minnellac — Thu, 03 Dec 2009 22:10:58 GMT

This may not be specific to your reference app, but I'd like to see an example of multiplexing the data into the dma from multiple modules running at different rates. This example shows how to extend the code to handle multiple modules, but not when they are running at different rates.

Nice example btw,

Chris

Re: cRIO Waveform Reference Application

Jeff_T. — Fri, 04 Dec 2009 22:18:01 GMT

Thanks Chris,

For multirate acquisitions the simplest approach is to allocate one DMA channel per rate and to make a duplicate copy of each rwfm VI for each FPGA acquisition loop. Certainly this approach is limited by the number of DMA channels you have available.

I've heard an R&D team here is researching a technology that would provide a multiplexing abstraction layer around one DMA channel that is scalable on the FPGA side. This would remove the DMA channel limitation but it wouldn't be available in the short term.

Best Regards,

Jeff

Re: cRIO Waveform Reference Application

minnellac — Mon, 07 Dec 2009 16:51:07 GMT

Yes, one DMA per rate is convenient when there are enough DMAs. I've worked an a number of applications where there aren't enough though. Right now, I'm working on one where I'm using a 9870, and the reference example I found to work with that card uses two DMAs right off the bat. I believe that a hybrid scan engine approach also ties up two DMAs.

I guess I'll look forward to that multiplexing abstraction layer material. I had posted a while ago with a proposed architecture for solving this issue, but it turned out that I had overhead issues when actually implementing it. I'm still looking for a good solution.

Chris

Re: cRIO Waveform Reference Application

J.R. — Mon, 01 Mar 2010 16:56:46 GMT

Maybe just an idea for the next release....

But wouldn't e useful to have this as an installer or a procedure to include those VI's inside the standard LabVIEW palette?

Could be nice... 😄

Regards,

Julien from NI Belgium

Re: cRIO Waveform Reference Application

falseth — Tue, 04 May 2010 14:14:55 GMT

Hi Jeff. Do you know if research on the multiplexing abstraction layer produced any results? I'm working on a project and this approach would be useful. I need to make the acquisition of several modules (1 to 😎 at different rates. Thanks in advance.

My best regards,

Vinicius

Re: cRIO Waveform Reference Application

Jeff_T. — Tue, 04 May 2010 18:28:48 GMT

Vincius,

My understanding is that technology is still in the resesarch phase so I wouldn't expect it in the near future.

Regards,

Jeff Tipps

S&V Systems Engineer

Re: cRIO Waveform Reference Application

esjensen — Thu, 27 May 2010 20:10:44 GMT

I am getting a "specified number of bytes could not be allocated" error in the rwfm_BufferCfg VI. I am not experienced enough to know what is the limit of bytes and how many I am exceeding it by.

I have closely mirrored the example for continuous acquisition. The samples per block is 40,000 and I see the buffer size is set at 400,000 (10x the read size). Is there a method available to determine amount of available memory?

thanks!

-erik

Re: cRIO Waveform Reference Application

Jeff_T. — Thu, 27 May 2010 20:28:19 GMT

I have typically started getting those errors around 30MB or so; I didn't investigate enough to know if it was a hard limit or if it was controller/application dependent. Also remember the total memory is 400,000 samples times the number of channels. Each sample in this implementation is 4 bytes so you are only allocating 1.6 MB per channel. You can use the RT Utility VI "RT Get Memory Usage.vi" to see how much your application is consuming before the DMA buffer VI is called.

My recommendation is to lower your factor from 10 to 5. If you have a healthy acquisition then 5 sill gives you plenty of margin to protect against overflows. Just watch the "Used Buffer %" indicator to see if your controller is keeping up or not. If it can't keep up then it really doesn't matter what the number is anyway.

If that doesn't help then let me know. Depending on your application there may be other options besides continuous acquisition.

Regards,

Jeff Tipps

S&V Systems Engineer

Re: cRIO Waveform Reference Application

esjensen — Fri, 28 May 2010 14:13:34 GMT

I adjusted the factor down to 5 and now get past the previous error. I only have a single channel and am sampling at 40kHz.

Now I get a -5002 error:

Error -5002 occurred at rwfm_AcqRead(1D_EncodedRaw).vi

Possible reason(s):

FPGA DMA Overflow

How can I determine what is the cause?

Re: cRIO Waveform Reference Application

DNgineer87 — Wed, 05 Jan 2011 01:41:33 GMT

The software requirements vs.. download filename in the "introduction" seem to contradict the "requirements" section at the bottom of the article. What file should I download for LV 8.6?

http://zone.ni.com/devzone/cda/epd/p/id/6206

Am I missing something?

Re: cRIO Waveform Reference Application

Jeff_T. — Wed, 05 Jan 2011 14:01:59 GMT

This is an issue with the publishing software that we use here to make these web pages. Version 305 is for LabVIEW 2010 and version 271 is for 8.6.

Regards,

Jeff Tipps

S&V Systems Engineer

Re: cRIO Waveform Reference Application

DNgineer87 — Wed, 05 Jan 2011 16:08:15 GMT

Thanks,

That's what I had assumed since the 2010 filename contained "305" and the real-time version was 3.5.

Re: cRIO Waveform Reference Application

Jinghang — Tue, 09 Aug 2011 17:02:52 GMT

I have some questions about this library:

1. I have installed this library by using VIPM, and it is supposed to appear under the User Libraries palette. but I cant find it there. see the 2 attached pics. Where can I find it?

2. I am using NI 9264 and NI 9205 modules, are they Delta-Sigma-Based C Series Modules or successive approximation (SAR) Modules? I dont really understand the difference of these two kinds of ADC methods.

Thanks.

Jinghang

Re: cRIO Waveform Reference Application

Jinghang — Tue, 09 Aug 2011 17:04:53 GMT

the labview I am using is 2009 sp1

Re: cRIO Waveform Reference Application

Jeff_T. — Tue, 09 Aug 2011 18:10:46 GMT

Hello jinghang,

1. The library should show up under user.lib. Do you have any other versions of LabVIEW that it might have installed to? Could you look in ../Program Files/National Instruments and see how many LabVIEW directories you have? Each LabVIEW directory fi you have more than one version of LabVIEW installed will have a user.lib sub folder. Try to find where those VI's went.

2. The 9205 is a "SAR" based analog input module. The 9264 is an analog output module which doesn't have support in the cRIO Waveform Library. I have been thinking about adding it but there just hasn't been that much demand for it. Typically analog output modules in cRIO are being used for single point control applications which is not the intended use case of this toolset.

The only difference between SAR modules and Delta Sigma modules is the way the sample rates are set on the FPGA. With SAR modules the sample rate is set with a "Loop Timer" VI and with Delta Sigma modules the sample rate is set with a property node.

Regards,

Jeff Tipps

S&V Systems Engineer

Re: cRIO Waveform Reference Application

Jinghang — Wed, 10 Aug 2011 15:48:41 GMT

I am trying to implement this application into my system, but encourtered a problem in the first step----Open FPGA reference.

I noticed you bind the function with a ctl document (attached). if I dont bind this function with proper ctl document, I would get a breaken wire (attached). Could you please expalin how to build the Type Definition in this application. in which VI you built the rwfm_Acq FPGA Ref.ctl?

Thank you!

Regards

Jinghang

Re: cRIO Waveform Reference Application

Jinghang — Wed, 10 Aug 2011 16:05:23 GMT

I opened the rwfm_CreatChan subVI and created the ctl document in its front panle. problem solved, I guess, sorry for the trouble.

Re: cRIO Waveform Reference Application

keenanball — Tue, 23 Aug 2011 14:14:26 GMT

Hi There,

First let me just say that this application is excellent!

I have several cRIO-9022 units with NI-9215 modules. I have been attempting to use this application to stream 4-16 channels of analog data to a USB HDD. To date I have been able to acheive the following using .tdms files:

100kS/s/ch on 4 Channels

50kS/s/ch on 8 Channels

30kS/s/ch on 16 Channels.

I would like to be able to increase the sample rate to 100kS/s/ch on 8 channels and 50kS/s/ch on 16 channels. To try an accomplish this I have attempted to write the data in 1D Scaled U32 per the poly vi and using the write binary vi. However, I can't seem to find a good Samples per Read value that keeps the RT Buffer Backlog [%] from increasing over time and then ultimatly overflowing the FPGA DMA.

1. Are the metrics for streaming to disk based on the internal memory of the cRIO or and extrenal USB HDD?

2. What is the best selection of Samples per Read for a given sample rate such that the FPGA buffer does not overflow?

3. What is the best method to extract the indivual channel information when using the 1D Scaled U32 method?

4. Along the same lines as 3 how do you extract the data once it has been written to a binary file.

I certainly appreciate your help.

Thanks,

Keenan Ball