1D Array of Digital Waveform

I have a 1D array of digital waveform and I need to work with the data from it. I can't seem to get the "numbers" from it to work with any array function or any other type of function for that matter.
I need to be able to convert these so I can find a particular value in the array.
Thanks.

Have you tried separating the array into individual waveforms using Index Array VI? You should be able to use the Get Waveform Components (Digital Waveform) VI on each wavefrom once you separate the array into its component waveforms. Then you can convert the digital waveform into a Boolean Array using the Digital to Boolean Array VI. You can then use boolean logic to determine when both waveforms output 1s.

Similar Messages

Memory leak in Digital Waveform

I have a program with a pretty serious memory leak that uses up all my system RAM and crashes my computer within a few hours of running the program.
The program takes an array of U16s where each bit represents a digital signal. The VI converts each U16 to a digital array and groups the resulting 16 digital signals into different busses for display on a Digital Waveform Graph. The profiler doesn't show any excessive memory usage in the VI. I put the whole VI into a Diagram Disable structure and moved a few pieces out at a time, and eventually the only thing inside the disable structure was the Digital Waveform Graph indicator. When this indicator is enabled, the memory usage of my system rises slowly and steadily until it uses all available RAM and crashes the system.
If I replace the Digital Waveform Graph indicator with a cluster, the memory leak still occurs (but much more slowly). I thought using the cluster fixed the leak until I reran the VI overnight while using the cluster instead of the Graph.
If I stop the VI before all the RAM is used, the RAM will not release until I close LabVIEW entirely. Once LabVIEW closes, the memory is released slowly and exponentially unless I use the "End Process" option in Task Manager.
This is a continuation of a previous post I made where I thought the memory leak was due to problems transferring data from an FPGA for display.
I ran the MemLeak vi (attached) on two separate systems, both running LV 2013 SP1, and got the same results. The memory leak is noticeably fast when using the enable structure connected to the Digital Waveform Graph but still present when using the cluster of Digital Waveforms.
Attachments:
MemLeak.vi ‏33 KB
LV shutdown.PNG ‏101 KB

Thanks for the replies.
In response to John's points:
1. The attached VI is a simplification of an FPGA VI that read a fixed number of samples from a DMA FIFO using an FPGA Interface Invoke Method approach. I'm using a card (PXI-7842R) that doesn't allow use of the Acquire Read Region method. In order to allow people without an FPGA card to hopefully see the issue, I replaced it with the for loop. Assuming that this for loop does leak (which I don't believe it does; as altenbach said, it's a fixed size allocation that LV should be able to reuse), why would I see a difference in the leak magnitude depending on which indicator I connect to the array?
2. I've previously reviewed the document you referenced, and I don't see any errors from it present in my code; do you? I have no global/local variables, strings/arrays displayed on front panel, property nodes, coercion dots, altered memory sizes, resizing/reallocations, etc. I don't see any weird buffer allocations. I used to have the conversion from U16 array to digital waveforms in a subVI but placed it on the same diagram to allow incremental use of the Diagram Disable structure.
3. The forum post you referenced had many of the items discussed above, plus it was solved using an RT FIFO. I'm not passing data from a producer to a consumer; I'm just displaying acquisition results. I guess you could say I'm processing the data, but I'm really only converting it to a format that the indicator will take; I'm not operating on the data.
It's good that the leak doesn't show up in 2014, but my SSP runs out in a couple of days; I never got an upgrade to 2014. This is the last item remaining on the development path, and we've already spent ~$4k to upgrade the controllers enough to display the acquisition without dragging down the CPU. I will be in hot water if I spent all that money and then end up having to scrap the display...

Convert digital waveform to array

Hello,
I posted a problem before Christmas regarding data acquisition and accessing the hardware buffer on a 6562 card. I managed to figure out that problem but now I'm stuck when I try manipulating the data I obtain. (The original problem can be seen here: http://forums.ni.com/ni/board/message?board.id=70&thread.id=7926)
Briefly, my application is clocking and synchronising an ADC board and then looking at the raw ADC data that comes back from the board. To provide synchronisation I am sending a sync pattern on one data line and using a second line to send a "start of frame" indicator, a '1' bit when I know that the board is synchronised. This line otherwise only sends ‘0’s. This cable is wired back into the NI card and LabView. All data sent uses the NI-SHDIO Generation Express VI and I'm using the Acquisition Express VI in parallel with the Generation VI to capture the raw ADC data when it comes off the ADC board. Since I am acquiring both the ADC data and the frame indication data (which I am looping by connecting that output DIO to an input DIO), the digital waveform essentially contains 2 arrays and I can view these from a graph indicator within LabView.
No problems so far. In order to manipulate the data and look at individual frames I am writing the ADC data to file. To extract the digital data from the digital waveform I am using the following VIs:
-Get Waveform Components
-Get Digital Data Components
-Write to Binary File
To view and manipulate the data I read it into Matlab and this is where I can tell that something's not right. When I read the file into a variable in Matlab, the variable becomes a 1D double array of 40,008 elements. This seems very odd, considering the Acquisition VI only takes 20,000 samples. When I look at the 1D array more closely it looks like the two arrays have been cross added in some fashion. The 1D array certainly doesn't match either of the two arrays visible in the graph indicator inside LabView. I can understand if the file is reading one array after the other (20,000 + 20,000 almost equals 40,008 after all) but that doesn't appear to be the case.
I would greatly appreciate some help on how I can extract the two data lines either using Matlab or LabView. Currently it looks like LabView is making a hash of things whenever I try to manipulate or extract the two arrays from the digital waveform. I have tried a multitude of different VIs and ideas but nothing appears to work.
The most straight forward way would be using the "Converting Digital Waveform to Binary VI" but it can't handle two arrays within the same waveform. (The result looks like the two arrays exclusively OR’d together). To combat this I tried running two Acquisition Express VIs in parallel (one for ADC data, the other for the frame info) but got an error message referring to invalid handles. I presumed this meant that I can't run two acquisition VIs simultaneously, judging from forum posts of users facing the same error message.
Sorry for the long post but I feel that I needed to fully explain the problem. I'm attaching my LabView code.
Thank you for reading,
Christian
PS. GenAcq2.vi is my code. Waveform_GenAcq2_Cfg.hws is sent by the first Generation VI; Waveform_GenAcq2_shorter_frame_indicators.hws by the second Generation VI.
Attachments:
CodeAndWaveforms.zip ‏126 KB
GenAcq_Screenshot.JPG ‏83 KB

The extra "8" is being caused by the fact that the "Write to Binary File" VI has a "prepend array or string size" input. Its default is true, and in your case you have it unwired, so you get the array size prepended. As for the rest of your issue, what are your Matlab commands to read a file? The following example VI, which generates a digital waveform and saves it to file,
can be correctly read into Matlab using the following commands:
fid = fopen('c:\temp\digData.bin','r');
F=fread(fid, [256,8], 'uchar');
Message Edited by smercurio_fc on 01-18-2008 05:26 PM
Attachments:
Example_VI_BD.png ‏11 KB

Coverting a boolean array to a digital waveform

Hello,
I have a 20 bit Boolean array that I need to convert into a digital waveform. Is there a easy way to do that?
Regards,
Kaspar
Regards,
Kaspar

Hi xdaf,
The reason why this VI takes in a 2D array is because this is often used to create digital waveforms with multiple channels and therefore, every row would correspond to data for each channel. To go around this problem, you may simply increase the dimension of your 1D array to a 2D array by feeding it in a Build Array function. Note that although you are increasing it's dimension, you are not adding any new data.
I hope this answers your question.
Message Edited by S_Hong on 12-03-2008 02:03 PM
S_Hong
National Instruments
Applications Engineer
Attachments:
Digital Waveform.png ‏2 KB

Simultaneous analog and digital waveform read with PXIe-6361 and BNC2120 ?

Hi there,
I am trying to collect both analog and digital signals from a PXIe-6361 linked to a BNC2120, using the attached VI. I am running Labview 2011 64bit. This is the first time I am working with digital input. On the 2120 board, I have the digital input BNC cable connected to User Input 1 and wire between the screw terminal of UserInput 1 and the P0.1 (Digtial I/O) screw terminal.
I have two questions related to this:
1) When I try to run the VI in its current state, I get the following error:
Error -89137 occurred at DAQmx Start Task.vi:3
Possible reason(s): Specified route cannot be satisfied, because it requires resources that are currently in use by another route.
Property: RefClk.Src
Source Device: PXI1Slot2
Source Terminal: PXIe_Clk100
Required Resources in Use by
Task Name: _unnamedTask<6>
Source Device: PXI1Slot2
Source Terminal: None
Destination Device: PXI1Slot2
Destination Terminal: RefClockInternal
Can anyone point me in the right direction for troubleshooting this?
2) I would like to combine my regular waveforms and the digital waveform into one array which would then be written to file. I can't figure out how to combine the two different waveform types...can anyone give me a hint on this?
Thanks for your help,
Claire.
Attachments:
Export Waveforms To Spreadsheet File (1D)_wo extra line.vi ‏33 KB
Multi-Device Synch-Analog Input-Finite Acq-Analog Start_Claire_wDigitalin.vi ‏105 KB

Hi ClaireJ,
Sounds like a reference clock conflict. This KnowledgeBase (KB) talks about this error when using simultaneous sampling. Also, might want to check the device routes in Measurement and Automation Explorer (MAX) as discussed here. Finally, if you are routing your PFI line over a RTSI connection, this error can occur. This KB discusses it.
As to your second question, this post should help.
Bill E. | Applications Engineer | National Instruments

How do I output three digital waveforms at once?

I posted this in Digital I/O, but now I think it's actually more appropriate here because it's not a hardware question. I need to output three digital waveforms at a relatively low frequency, 71.9 Hz. I have a PCI DAQ card, the 6024E and am using the NI-DAQmx functions to try to do this. My program basically generates the square wave that I want, and converts it into a digital wave. I do this 3 times for the three separate waves, and then I combine them into an array and send them to my DAQ functions, which are in a while loop so I can get continuous output. My problem is that the waveform that the DAQ is actually outputting is not what I want. It's outputting a wave that has the same duty cycle (approximately) but the frequency is over 2 kilohertz. It's not like this all the time; after it outputs about 7 cycles of this wave, it goes to logic low for a long time, and then repeats itself. When I probe the digital waveform right before it goes into the DAQ functions, it's running correctly at 71.9 Hertz. Am I doing anything wrong with the DAQ functions or the sampling information? Thanks in advance.
-- Josh Matloff

Hello Josh,
I'm pretty sure that the reason that your digital waveforms are not being produced at the correct frequency is because your digital output is not associated with any sort of timing. Unfortunately, with an E series board you can only do software timed digital operations. This means that the frequency at which the values on your digital lines will be updated depends on how fast/often your computer executes the DAQmx Write that is inside of your while loop. If you have an M series board, you can actually correlate the DIO operations with another subsytems clock (AI/AO sample clock, etc.) which means that you can acheive hardware-timed DIO. In the event that you do not have access to an M series board, I think that AnalogKid2DigitalMan was spot on that you would want to use counters to generate pulse trains (that is if your digital waveforms have a constant duty cycle and period). Depending on what the DAQ board is outputting to, you might also want to consider using the Analog Output channels to generate your digital waveform. As long as you continue to use the digital lines on the 6024E, there is not really a way to guarantee the timing of when the digital lines will be updated. You might be able to get close, but you will probably see some "hiccups", especially if your computer needs to service interrupts or give processing time to another application. And lastly, heed geckoee's advice and don't forget to properly close out your tasks! Putting in some error handling may also help in the debugging process.
Take care,
E.Lee
Eric
DE For Life!

How to do a digital waveform subtraction

i am trying to subtract two digital waveform using subtract operation, but it seems that the subtraction opertation doesn't like digital waveform.
error message:"You have connected two terminals with different types. the type of the source is digital waveform, the type of the sink is double"
anybody can help? please.

Hello,
See the attached modified example. Now you can access data in a 2D array .
Software developer
www.mcm-electronics.com
PS: Don't forget to rate a good anwser ; )
Currently using Labview 2011
PORTUGAL
Attachments:
dither tech2.vi ‏57 KB

How do I sample a digital waveform?

I have a digital waveform that represents a 1-bit data stream. The bit rate is 1Mbit/s (i.e. For a value of '1' the line is high for 1us, for '0' the line is low for 1us).
I want to create a numeric array representation of the line by taking a sample of it every 1us and appending it into an array.
How do I set it up in LabVIEW to sample the line at 1MHz and create a 1-D numeric array of the bits?

Hi Raine,
It sounds like you're trying to keep data from previous samples in memory through the next iteration of the sampling loop, then append the new sample to the array.
Using shift registers is the most reasonable option. To create a shift register, wire your sample data to the edge of your sampling loop then right click and select Replace with Shift Register. You can then use a Build Array function to connect the shift register data with the current sampling data.
Cheers.
| Michael K | Project Manager | LabVIEW R&D | National Instruments |

Generate digital waveform form a read from spreadsheet.vi

Hi, I'm very new to LabView and am having some problems in completing what I believed would be a very simple task.
I am using the Read from Spreadsheet.vi to read in an Ascii tab delimited file that I created in Matlab (the file is simple a vector of 1's and 0's that represent a binary stream) All that I want to do is take the output from this and generate a digital waveform corresponding to the 1's and 0's in the array but I cannot find a way of doing this.....
Help much appreciated,
Thanks.

You should be able to just run your data straight in to the digital write function as long as you select the correct port width of your hardware.
If you want to do it with a digital waveform it's a bit trickier, the digital waveform data type is a surprisingly complex animal.
There might be a better way to do it, but this is what I've had to do in the past...
The "build digital data" function needs a 2D array in, so convert your 1D array into a 2D.
Then the digital data can be input into a Build Digital Waveform.
Then the digital waveform can be output with the write digital waveform.
Message Edited by Troy K on 03-23-2008 11:37 AM
Troy
CLDEach snowflake in an avalanche pleads not guilty. - Stanislaw J. Lec
I haven't failed, I've found 10,000 ways that don't work - Thomas Edison
Beware of the man who won't be bothered with details. - William Feather
The greatest of faults is to be conscious of none. - Thomas Carlyle
Attachments:
array_to_digital1.png ‏4 KB
array_to_digital.png ‏9 KB

How plotting on a digital waveform graph the bit transition in function of the time

Hi everyone,
I am using LabView 6.1 on a Windows XP computer. I am to plot output bits sequences on a digital waveform graph just before sending the information to a board.
So far I can see the transitions for my 16-bit port (16 plots) but the width of a pulse is always identical, no matter what times I enter. I wired my 1-D array timestamps to the property node Xscale.MarkerVals[] of my digital waveform graph... but it doesn't seem to affect my plotting...
Thanks in advance for any help concerning this problem.
Jonathan Sabah

Well here is piece of my VI with the necessary sub VI.
I also want to hide/unhide plots... I have found how to hide.. but cannot figure out how to unhide.
Any help please ?
Thanks again
Jonathan
Attachments:
Exemple.vi ‏58 KB
Setup_DIO64_for_Output_1.0.vi ‏111 KB

How to playback a digital waveform

Hi I would like to do some post processing work on a digital graph data. I would like to use 2 seperate VIs for data acquisation and post processing. So first I acquire the data then pass the whole waveform data as an input to the other subVI but I olways get the last waveform . Could you please let me know how I can pass the whole information about a continous digital waveform without saving it on disk
thanks

You can do a variety of things, such as building an array of waveforms by auto-indexing them where you wire out of the aquisition loop. Alternatively, if you want just a single long waveform, the Append Waveforms.vi (Functions -> Programming -> Waveform -> Analog Waveform) should do nicely. You can also manipulate the waveform components directly and append the data arrays if you want some more control over it, but that's pretty much what the built in vi does.
The Colex Group
Lead Software Engineer
Certified LabVIEW Developer

How to control individual channel of signal generated from digital waveform generator?

Digital waveform generator has 8 channels. I need to generate two different signals to HSDIO. How to modify and control two different channels? Also, how to translate pin outs from PXI-6541 to channels? I need to control signal into pin 1,3,29,and 31 individually.
Thank you!!
Solved!
Go to Solution.

You must combine your individual data into an array. The digital waveform is simply a digital representation of the binary array. It still boils down to bit 0 of each array element going to channel 0 (or the first channel you specify in Create Dynamic Channels). The next bit goes to the next channel. My last post is quite clear. To display the array in binary, right click on an array element, then select Display Format, then select Binary. You can also right click on the element, select Visible, then select Show Radix to display the small b before the number. One more thing, in the Display Format window, uncheck the box next to Use minimum field width. Then set the numeric just under the box to 8. Then select Pad with zeros on left in the box below.
You should not use waveforms until you learn more about how the HSDIO operates on input data. It isn't hard to combine waveforms, but it also isn't as clear as using an array of U8 or U16 or U32.
Trying to explain further. The first number to be writen to the HSDIO will have this effect: Bit 0 (LSB) of the number gets written to the first HSDIO channel you specify. Bit 7 goes to the 8th channel you specify. If you don't specify 8 channels, the bits get ignored. So wiring in one number will produce only one bit on each channel. In other words, the number already combines the bits of all the channels you specify. You don't combine anything yourself. Look again at my picture on my last post. By wiring in an array, you cause a bit pattern to be generated.
I hope this is more clear.
- tbob
Inventor of the WORM Global

Digital waveform to boolean value

Hi, I have a digital waveform and I want to be able to light up an LED on the front panel every time the waveform is high...
What is the best way to do this?
I know there is a vi that converts a digital waveform to a 2D boolean array, but I just want a single boolean value.
Thanks!
Sunny

Hi
In reference to my previous post, you can just leave the inner for-loop, but you have to extract the 4 channels.
Just have a look at the picture.
Hope this helps.
Thomas
Using LV8.0
Don't be afraid to rate a good answer...
Attachments:
DigitalWaveform.png ‏6 KB

Counting number of 1's present in digital waveform obtained by converting the pulse signals.

Hello,
I am using Analogtodigital.Vi for converting the pulse sequences into digital.signals.I am able to get the digital waveform representaion of the pulses.
But how to count the number of 1's present in the converted digital waveform.I want to count the number of 1's present in the converted digital waveform.
Thanks in Advance.
Solved!
Go to Solution.

Did you try opening the block diagram of Analog to Digital.vi?
It creates an uncompressed 2D array of 1s and 0s which represents the 16-bit binary A/D conversion of each element in the Y array of the input waveform. You can use the DWDT Digital to Boolean Array.vi to convert to a 2D array of booleans. Then convert the booleans to 1,0 and sum the array of integers. The sum should be the count of 1s in the digital waveform.
Lynn
Note: The attached VI is saved back to version 8.6. When I saved it for Previous Version a warning was generated about possible differences in versions. Let me know if it does not work, and what version of LV you are using.
Attachments:
Count bits.vi ‏25 KB

Digital waveform editor can not open hws file generated by niHWS store waveform

Hi,
I am using a simple VI to store the U32 array to a hws file in LabVIEW, however, the file generated can not be opened by Digital Waveform Editor. The VI used to be working well before I upgrade LabVIEW from V7 to V7.1.
Meanwhile I also found out that the hws file generated by DWE can not be read out by niHWS. retrieve waveform.vi if the number of channels is not 32.
I would be grateful if any one can give me some help. Please find the VIs and hws files as attached.
The software I am using is
Digital Waveform Editor 1.0
LabVIEW 7.1
Best Regards, YJ2003
Attachments:
question Get ArrayU32 from HWS Data.vi ‏108 KB

Dear Brian,
Thanks for your quick response.
I tried again but still failed to open the hws file with my DWE V1.0. Since the version is the only difference between our software, I suspect the problem is caused by my DWE of old version.
Would you please help me to check if the new attached questionretrievepattern.hws file can be opened by the HWS.VI? (Please change the extention from txt to hws as I can not attach file with hws format in this forum)This file is generated by DWE1.0 and contain only 16 channels. It can not be opened by the niHWS retrieve waveform.vi in my computer with erroe code "-21558", but if I added another 16 channels signals with DWE, the data can be read out properly.
If we can confirm the problem is caused by DWE1.0, would you please also let me know how to upgrade my DWE? Thanks.
Best Regards, YJ2003
Attachments:
questionretrievepattern.txt ‏35 KB

1D Array of Digital Waveform

Similar Messages

Maybe you are looking for