Digital Waveform Attributes, ignored by LV ?

I've used waveform attributes before to rename plots on graph legends. Today I tried the same on a digital waveform graph, but it won't work. Can anyone tell me what I'm missing/doing wrong ? I'm using NIHSDIO VIs in this instance, when this worked for me before I was using DAQmx VIs. I have no attributes to edit, but have tried inserting them. The pictures should explain. i.e "Line 0" should be named "one"
Message Edited by bmann2000 on 08-14-2008 04:26 PM

Hello bmann2000,
This is a behavior that has been seen and reported as incorrect in the past. However, it has not been corrected yet. Even if the ChannelName is set correctly, the graph will not update the channel names for a digital graph. The solution, however, is a bit more complicated than with analog data since each channel can potentially have multiple lines, each with a different name. In any event, you can work around this naming issue by updating the plot names programatically. I have attached an example.
Brian Coalson
Software Engineer
National Instruments
Attachments:
DWFM_NameAtt.llb ‏98 KB

Similar Messages

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.
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Digital Waveform Graph refuses to edit Bus names

I am trying to display digital waveforms on graph whose lines are grouped. It looks like the functionality exists to group the lines into "Buses". There appears to be a way to rename each Bus from its default "Bus 0, Bus 1, etc." since there is an Express VI called "Group Digital Signals" that does it. It looks like the express VI is editing the attributes on the waveforms in order to rename the Buses. The attributes are NI_ChannelName for the Bus and NI_LineNames for the lines that make up the bus.
When I code it, the Line Names are renamed according to what I want, but the Bus names remain default Bus 0, Bus 1, etc. Is there something I must do to rename the Buses?
(see attached VI)
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Solved!
Go to Solution.
Attachments:
Digital Graph.vi ‏26 KB

So Young Daniel, do you mean like this?
All I did was select where is said Bus 0,1 or 2 and typed in a new value.
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"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

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

Hi there,
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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?
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Thanks for your help,
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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.
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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.
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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

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.
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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

How to send digital waveform to the DAC?

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How do I sample a digital waveform?

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Hi Raine,
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Bug in Digital Waveform Graph X-Axis

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I am making separate queried to a database to retrieve analog and digital data over the same time period. The data were logged at 2 second intervals. I have verified that both result sets return the same number of values with the same t0 and dt. I then plot the analog values on an XY Graph and the digital values on a Digital Waveform Graph. I then use property nodes to sync the two graphs (left and right plot bounds, XScale.Range, and Cursor Position.X). After doing this, I can see that the datasets do not line up between the two graphs. The data on the Digital Waveform graph ends several seconds sooner than the analog data. The x scales of the graphs appear to match but the plots don't align in time.
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There is a much simpler way to synchronize these charts. Just use a stacked chart.
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Digital Waveform graph with a lot of samples

Hi,
I have to display in a Digital Waveform Graph a lot of data read from a file(2.000.000 of samples for 36 signals). If I read the file and I try to display all the data, the Vi became unusable. For example, to zoom a graph region, it may take 30-40 seconds, scroll is impossible ecc, ecc..
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Hi Garraty,
Excuse me but I have several questions for you.
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Kind Regards
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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.
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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.
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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...

Generate digital waveform form a read from spreadsheet.vi

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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

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Attachments:
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Digital Waveform Attributes, ignored by LV ?

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