Quantcast
Channel: All LabVIEW posts
Viewing all 204074 articles
Browse latest View live
↧

Labview FPGA Data Rate control with detector response

June 6, 2017, 1:28 pm
$
0
0

Hello All:

 

   I am at my wits end so I put myself at the mercy of the Ni Community. My project is as follows:

 

I have a 9229 Module collecting data at a rate of 50 Ks/S with my CRIO. It is then passing that collected data to the Host Loop. Simultaneously, I am controlling a Spectrometer which is suppose to be moving to specified wavelengths. The object of the exercise is to move to a wavelength, get and sync the detector response (voltage handled by the CRIO) and then plot (graph) the two together.

 

I have tried many things and have the following problems:

 

1. The data rates are always incorrect (seems lagging) when the data is transferred to the host loop

2. I cannot seem to get the correct voltage response to correlate with the corresponding wavelength (either correlate with time stamp, etc)

3. My Data FIFO keeps getting full and timing out

 

 

Attached screenshots of my VIs

 

I tried running loops in parallel but they would not start at the same time. I tried synchronizing them but that was an utter failure.

 

Please Help! Thanks!

 

 

↧
Search

Re: .NET Month Calendar control and User Events

June 6, 2017, 1:39 pm
$
0
0

Ben - Thank you for the help. Learned something too!

↧
↧

Re: Removing Global Variables

June 6, 2017, 2:04 pm
$
0
0

I agree with what has been said.  As a side note, since you mentioned that everyone tells you to avoid globals, check out this thread:

I Like Global Variables

They are good if used right

↧

How to determine the size of the data in an excel worksheet using Actice X?

June 6, 2017, 2:11 pm
$
0
0

What is the method or property to use to determine the data size of an excel worksheet using Active X?

 

Thanks.

 

Ian

↧

Re: Managing U16 images in Labview/IMAQ Vision

June 6, 2017, 2:18 pm
$
0
0

Probably better to create a new thread and refer to an older one with a link.

 

From the 2015 Help, it looks like U16 images are supported by IMAQ Write (TIFF), but probably not supported by other software that reads TIFF, as noted in the help.

IMAQ Types.png

↧
↧

Re: How to determine the size of the data in an excel worksheet using Actice X?

June 6, 2017, 2:32 pm
$
0
0

There is an Excel Get Last Row function.  Ctrl+Space in the block diagram to search for it.  Is that what you are looking for?

↧

Re: Synchronizing Multiple tasks (reference triggered)

June 6, 2017, 2:33 pm
$
0
0

the devices I am using are 5 NI PXIe-6368 multifunction DAQs

which vi or property node is used to do that?

↧

Re: Encoder signal acquisition using USB 9233

June 6, 2017, 2:34 pm
$
0
0

Shaila,

 

It is my understanding that you would like to use an edge from an encoder signal to trigger sampling of a sensor. Using your current implementation, that trigger will need to come from software since you are detecting the edge in software. However, software triggering does not guarantee synchronization. This means that the time at which you sample the sensor signal will not necessarily correspond to the time at which the edge of the encoder signal occurred. The sensor will be sampled at some point in time arbitrarily later than the encoder edge. If this is not a problem, you can use your proposed method to capture the sensor signal. If you need the sensor to be sampled at the same time, or within a short time of the encoder edge, then you will need to use some form of hardware trigger.

 

A few things to think about in designing your solution:

Encoder outputs are digital signals. (You can read them as analog, but it is currently obfuscating and overly complicating your code.)

Using Basic DAQmx Functions

Triggering in LabVIEW

 

To answer your specific question, your code should work with a real signal, provided it works with a simulated signal. However, I am not convinced that your posted code will accomplish your goal. If my understanding of your problem is incorrect, I would be happy to offer additional assistance if provided further details, particularly about any additional hardware available to you and the purpose of your application.

 

Duncan W.

↧
Search

Re: Managing U16 images in Labview/IMAQ Vision

June 6, 2017, 2:34 pm
$
0
0

Oh I am sorry about that.

Yes I also noticed that U16 is supported by IMAQ Write File 2, as in the help document. But how can I specify this parameter? You know there are only three variables in the TIFF Options: Rows Per Strip, Photometric and Compression Type.

I then found a function called IMAQ Image Bit Depth, but it seems this function only applies to saving pngs.

Thank you so much!

 

My version is 2016.

↧
↧

Re: RS485 2 wire on NI 9871

June 6, 2017, 2:36 pm
$
0
0

Steffen01, 

The NI-9871 does support RS485, so a converter should not be necessary. Is there a timeout error code that you can provide? What software version are you using? 

 

Angela L. 

National Instruments

↧

Re: crystal reports

June 6, 2017, 2:40 pm
$
0
0

Hello,
The printer "doPDF 8"  may not be correct.
Try to set the input from the reportsource  unlinked with OpenReport.
Try the llb of the previous post.

↧

Re: How to determine the size of the data in an excel worksheet using Actice X?

June 6, 2017, 2:41 pm
$
0
0

Aputman,

 

Well, I need to know the numbers of the last row and the last column, and also I would like to read all the data of an excel worksheet dynamically from LabVIEW using ActiveX, assuming I do not always have Report Generation Toolkit.

 

Thanks.

 

Ian

↧

Re: Copy entire folder into another folder on USB drive

June 6, 2017, 2:42 pm
$
0
0

Thanks Duncan,

 

I was able to get this to copy files to different directories on the same SD card, but now I'm having trouble getting it to copy from the SD card to the USB drive. My paths are as follows: SD card - /u/Source   USB drive - /v/Destination, following the procedure in the article you posted. No error is thrown, just nothing gets copied to the USB drive. I have written to the USB drive before, so I know the format is ok.

↧
↧

Re: Vision Acquisition Software

June 6, 2017, 2:50 pm
$
0
0

I would check the readme for the version of VAS that you installed and check to see if it is compatible with LabVIEW 2017 because I could not find a version of the VAS driver that is available on the web that is compatible with LabVIEW 2017 (yet).

↧

Re: Copy entire folder into another folder on USB drive

June 6, 2017, 2:56 pm
$
0
0

Actually never mind, just got it to copy to the USB drive. It only works when I concatenate the outputs of the list folder function. Not sure I understand why.

↧
Search

Re: How to determine the size of the data in an excel worksheet using Actice X?

June 6, 2017, 3:06 pm
$
0
0
TulaRen wrote:

.... assuming I do not always have Report Generation

Why would you not always have it, if you sometimes have it?  I'm not sure what that statement means.  Smiley Wink

 

If you do have it, the Excel Get Data VI will return an array of data for the entire worksheet, if the Start and End values are left unwired.  

 

If you don't actually have the RGT, I don't know what to tell you.  There has been another toolkit mentioned before but I don't remember the name.  The code for the RGT is not password protected so it's easy to open the block diagram and see how to do something.  However, in order to recreate that functionality, it would be a rather time-consuming endeavor, especially if you "don't always have Report Generation Toolkit."

 

 

↧

NI 9514 Force Control

June 6, 2017, 3:58 pm
$
0
0

I am new to motion control in labVIEW. I have Voice coil actuator I am trying to control using a load sensor as an analogue feedback. 

 

And this thread:

http://forums.ni.com/t5/LabVIEW/Closed-loop-control-in-force-How-to/td-p/1449700

 

I have tried to follow what this person did in their example. But I could not get it to run due to issues with configuring the FPGA reference for the NI 9237. So I modified the approach slightly with two FPGA vi's one filling the data buffer and one for the servo interface but I still modified the PID input to use the analogue input and not the encoder. I get the -63195 error when I run the RT code. 

 

I attached my code for reference. 

 

Has anyone gotten an application like this to work? Or is there a simple way to perform open loop control with the NI 9514? From what I have read it didn't look like the NI 9514 is readily setup for open loop control.

 

 

 

↧
↧

Re: Copy entire folder into another folder on USB drive

June 6, 2017, 3:58 pm
$
0
0

A few more questions. My current VI will copy data from the SD card to the USB drive only if there is only file on the SD card. Any more and error 7 gets thrown. Also this does not iterate through the entire folder, it just copies the latest file. Any ideas on how to fix this?

↧

Re: Open a .mat file in Labview

June 6, 2017, 4:04 pm
$
0
0

Bundle of thanks for the reply

Okay I saved the file as delimited text and then run through the Labview file I get an output where values sometime reaches amplitude of 6 while if I plot the same parameters using orignal matlab my output alway lies within -4 to +4 range. 

What might be the reason for the change in parameters

↧

Re: Sampling Rotary Encoder- Error -201319

June 6, 2017, 4:09 pm
$
0
0

Hi Jeff,

First, thanks for the answer, also could you show me an example for using this property node, as location inside block diagram and connection for correct operation?

Thanks again.

↧
Viewing all 204074 articles
Browse latest View live
Search
<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>