how to sync pxi-6341 Analog Out to pxi-4304 Analog In

April 8, 2016, 9:57 am

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I have a PXIe-1082 chassis that contains a PXIe-6341 and a PXI-4304 module.  I'm outputting a sine wave from pxi-6341.Ao.0 channel to the pxi-4304.Ai.0 channel.  The pxi-4304 isn't capturing any signals until about 75 msec later. How do I sync timing between the 2 modules together to stop this loss of data?

 

(Eventually, I'll be running a digital waveform out of the 6341 and into a device while the 4304 captures analog response of the device. So I'll need to have everything sync'd up.)

 

Thank you for your help,

Ron

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Strange 'Read from XML' performance issues

April 8, 2016, 12:19 pm

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I was recently benchmarking the "Read From XML" VI to troubleshoot a performance problem I am having, and I have found some really odd behavior. 

 

If I generate a large array of clusters, using the code below, the performance is quite acceptable. "Read From XML" takes around 70 ms to process a 4900 element array:

 

Here are charts of the execution time versus array size, and character count versus array size: 

 

 

The performance of "Read From XML" drops by orders of magnitude if I encapsulate the array of clusters inside another cluster, like shown:

 

The execution time versus the number of elements, and the string length are below:

 

 

So while the string length is essentially identical between the two files, the execution time is 70 times slower, taking almost 5 seconds to process a 4900 element array, when a cluster encapsulates the array. "Unflatten from XML," "Flatten To XML," and "Write XML" all perform well in both cases. 

 

Is there any explanation for this performance hiccup, or tricks to circumvent it?

 

How to convert wav to rso files

April 8, 2016, 12:36 pm

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I have used a text to mp3 convertor to get mp3 files. I then used itunes to change these files to .wav files. Now i am needing to get them to rso files but the one main thing I am finding online is NeXT Tools to use to convert wav to rso and it is not opening once i downlad it. I am running on OS and any help is appreciated I am running out of time. The end goal is to hopefully have the robot read out the appropriate color of a marble that it see's based on reflected light values. Thanks

MFC control with NI 6008

April 8, 2016, 3:12 pm

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Hello there and thank you in advance for any responses,

 

(FMA-2109 Datasheet Attached)

 

I have a mass flow controller (Omega FMA-A2109), which can be remotely controlled (0-5V signal) and you also read the flow output (0-5V or 4-20mA output). The controller also has potentiometer on it for the user to control the flow manually. To bypass the manual control, you need to make sure there is no jumper between pin #2&5 of the DB9 connector. My issue is that I can read the flow and control it manually no problem but I'm having trouble controlling the flow remotely. I'm using the NI USB 6008 to read and control the MFC. the manual says to connect pin #2 and 5 to your remote variable voltage source so i just connected to AO 0 and GND of my DAQ. When i change my analog output voltage (verified the voltage changing with DMM), the flow does not change. But i can still change the flow manually with the pot, which is weird. So i'm not sure what's going on. I also tried connecting a variable voltage power supply (instead of using the DAQ) and controlling the flow with that but no luck.

 

Am i missing something? Could this be an input/output impedance mismatch issue? Please advise, thanks!

 

-Serge

Why "Limit maximum instances of this event in event queue" in the Edit Events Dialog Box?

April 8, 2016, 3:32 pm

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Why would I "Limit maximum instances of this event in event queue" in the Edit Events Dialog Box?

 

 

I think this is new to LV 2014, but I couldn't find any explaination of a good instance to use this . A search on NI shows only the 2014 Help text, which explains what it does, but not why?

 

Does anyone know of a good case to use this option?

 

Thanks in advance.

Justin Tyme

 

Only output a single value from a nested case structure

April 8, 2016, 6:23 pm

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I am reading a barcode and based on which bars are present, I want to assign a value. I have set up nested case-structures to assign values for each of the possible set-ups of bars that are present. Now i am trying to figure out a way to only output the value of the one case that is true. Is there any way to do this? 

Sum values from array, then take percentage.

April 8, 2016, 6:54 pm

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New to labview this is probably really simple but I am hitting a road block.

 

I am using a DAQ device to read in 3 values continuously.  I want to take these three values and get the percentage of each one from the total, the output to a graph the %.  I'm not sure how to get the sum of the values from the array.

 

For example:

 

Value 1 = 7

Value 2 =5

Value 3 = 8

 

Sum = 20

 

Value 1 % = 35%

Value 2 % = 25%

Value 3 % = 40%

 

Thanks for any help.

Is possible to return an .exe to a VI ?

April 8, 2016, 8:24 pm

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I have this issue, i need to recover the VI that I made, but the only file I have now is the .exe, lost my whole program in Labview, is this possible ??? ASP

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Measurement issue in Yokogawa WT3000E

April 8, 2016, 10:06 pm

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I have interfaced WT3000E with Lab view 2013, but i'm are facing an issue in measuring Phase shift. I have measured Voltage, Current, ITHD, User Defined Functions , but when i try to measure  φ U2-I2,  φ U2-I3 in lab view, i'm are getting the Measurement Function but not the value ( i.e., displaying NAN).I have changed the wiring settings toΣA in Meter.  Is this due to Wiring settings, since all other parameters are based on Element1,2,3,&4, whereas phase shift is base on ΣA. Can you please help me to sort out this issue. Thanks in advance.

Is it possible to create several cursors on a graph by importing a table of points?

April 8, 2016, 10:47 pm

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I would like to create several drag free cursor lines on a graph based on points on an already prepared table. Also, when I drag cursors to a new position, I would like to be able to generate a modified table of points when the cursor position is changed.

Basically I want to generate cursors from a table and also be able to update that table ( or even create a new table) based on the positions of the cursors or by changing cursor positions.

Does anyone have an idea of this is possible and how it maybe implemented?

Thanks .

stepper motor controller

April 9, 2016, 2:40 am

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Hello every one....

     Let me help to find a ni  low cost stepper motor controller with supportable of labview programming.....controller will be single axis with low current is also ok....plese share your ideas

   Thank you...

DigitalSartandStopTrigger.vi not working with DAQ USB-6341

April 9, 2016, 4:12 am

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Hi,

 

I was using the DigiitalStartandStopTrigger.vi from http://digital.ni.com/public.nsf/allkb/BA775B0E445BFA79482571FE0032CCEB successfully last year to acquire analog data from a NI-DAQ USB-6341 using a PFI trigger rising and falling edge to start and stop the acquisition.  However, I have recently tried to use the same code and I have seen that nothing at all happens - it seems like the atart and/or stop triggers are not seen at all by Labview, but apart from that I cannot really understand more about what the problem is.  As far as I know, nothing on my system has changed since the last time I used the code and it worked.  I am still using the same version of labview (2013) and exactly the same DAQ board. The connections are all good, as I can open NI MAX and see that the PFI port can be read as input (one of the 7 lines is active).  

 

Can anyone help with this?  I am a little bit desperate as i have been trying to solve this for a while but I simply cannot see any reason at all for the code to stop working only a few months after it was working perfectly.  Any advice or suggestions as to how to understand and solve the problem will be very gratefully received!

 

Thank you!

Anna

myRIO Optical Encoder express VI Angular position and speed.

April 9, 2016, 5:24 am

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Hi, I am a systems engineer student and I would like some help on acquiring angular position or shaft postion from an encoder connected via myRIO. From using the Encoder express VI, I am able to get the counter values and counter direction. Is it just maths that I need to be able to calculate the shaft position? The encoder I have has 1024 cycles per revolution (CPR).

 

I have searched how to do this, but can only find how to do it with a DAQ assistants, which has the option to measure linear or angular postions. Does myRIO have similar express VIs to this?

 

openG runtime library

April 9, 2016, 7:39 am

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Dear all,

 

First, I made a program (application built in LabVIEW 2012, 32 bit) with OpenG code for free distribution to a governmental public organization "internationally".

I built the application in normal way of LabVIEW function (not OpenG application builder).

 

As shown in the attachment, a switzerland user reported some unexpected error related to OpenG code in the application.

He seemed to install a runtime library from ni.com but he insisted OpenG part of application required some extra run-time library for it.

 

I am sorry not to provide any more information on his computing configuration.

Can you let me know any guide to fix this trouble?

I have never seen this kind of trouble during almost 10 years experience with LabVIEW and OpenG.

 

Best,

 

labmaster.

*)This was also posted on Lavag.org

Limiting the duration of .tdms signals in LabVIEW

April 9, 2016, 8:33 am

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I have downloaded the ecg samples from Mit bih database. The signals are converted to .tdms format and then imported to LabVIEW but they seem to have a 30min duration. How can I limit .tdms signals to 1min signals in LabVIEW?

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error 20309

April 9, 2016, 8:58 am

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Hello,

 

I received this kind of error :Error -20309 occurred at Amplitude and Level Measurements->practice.vi
 (waveform index 0 of 1). Possible reason(s): Analysis:  The amplitude of the waveform is zero, so the histogram method cannot be used.

 

I'm connecting the amplitude and level measurements to  a waveform chart. and i received this kind of error. Please help to solve this kind of problem.

 

Thank you

FPGA

April 9, 2016, 9:06 am

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Hello,

 

I am trying to make a case structure run only one time whenever it is called. I have tried various attempts using a feedback node but I can't get it to work. First call won't work because the inner case needs to run whenever the two outer cases are true. No event structures can be used in an FPGA. This really has me stumped. I must be overlooking something really obvious. Attached is the frame work which I am using.

The ultimate goal is to have a subVI in the inner case structure run only once. Any suggestion on solving this would be greatly appreciated.

 

Thank you,

Dave

In my array there are some values as inf and Nan, Before to save my array I want to eliminate this values. How can I do this?

April 9, 2016, 9:58 am

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In my esperiments I obtain some values such as inf and Nan, and I want to eliminate this values before to save my array in a file because then I would take the average of these values that are saved in a file

How can I do this?

 

Thanks

ASCII number decimal point display issue

April 9, 2016, 12:21 pm

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Having a weird problem with a Plug-n-Play driver for the Keysight/Agilent/HP 8510C.    There is a VI driver (attached) called "Output Active Marker.vi"

 

The problem I'm having with this VI is that it works perfect when my marker value is between 9.9999 and -9.9999.    

 

When the marker value goes between 99.999 to 10.000 or -10.000 and -99.999....the VI does not shift the decimal place on the DBL Indicator.   For example:   a marker reading of -15.347 would display -1.534

 

Also, when a reading above 100 or below -100 is dicplayed, it has the same issue with the decimal point.       Example:  -104.56 reads  -1.04

 

I pulled-up the Agilent Key word Dictionary for this function (located here:   http://www.keysight.com/upload/cmc_upload/All/08510-90280_8510KeyWords.pdf ) and it states that the output is an ASCII string, not a DBL number. (page 515 & 516)

 

I tried taking the base VISA Read and Write functions and output directly to the Read string output....but it has the same problem.

 

So, It looks like this VISA Read function is not playing nice with the 8510C.....does anyone have an idea of how to "fix" it?

Appending images in several spreadsheets of an excel file

April 9, 2016, 12:22 pm

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Hello!

 

I'd like to know how could I append images to different spreadsheets of the same excel file. Currently I am using the report generation toolkit (append image to report VI). Using the MS Office cluster i can set the position of the image within the first spreadsheet of the excel file.

However I would like to append two images in the THIRD spreadsheet of the excel file.

 

I am generating a TDMS file first, where i define the different spreadsheets or tabs of the file, and afterwards i am converting it into an excel file. How could I set the location of the images in a concrete spreadsheet of the file?

 

Thanks a lot in advance!