Realtime numeric display of waveform data in SE

Hi all,
I am a new user to SE and I am trying to display a realtime numeric indicator of strain values collected with an scxi 1520 conditioner via scxi-1600 usb daq.
My problem seems to center around the fact that my strain values are "waveforms" rather than scaler. The "view as" option in Data View only has waveform and XY for options.
Is there anyway to display numeric indicators of the wavform Y data values for each strain channel?
Also, does anyone know if there is a new version of SE (I'm currently running SE Lite 2.5.0 evaluation version) that includes a way to aviod having to hit the "show all" button to update the preview display? In a perfect world, I would like to display numeric indicators and real-time strip chart type plots of each strain channel that are about 1 minute long and update the 10Hz data every 1 second or faster.
Thanks in advance to everyone for monitoring this forum.

Phil,
Changing to 1 sample with a sample period of 500m worked great. I kept running into buffer overflow errors when trying to log at 10Hz with the 32 strain channels though. Do you have any idea how I can increase my buffer size?
I have two other quick questions if you have time.
1. Is there anyway to change the default channel name that displays on the meters (it is currently SC1Modx/aix)? I was able to change the group name, but not the individual channels.
2. When I export to excel each channel opens in it's own worksheet. Can I automatically open them in one worksheet?
Thanks!
JB

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Waveform data not displaying correctly

Hello,
I am having some trouble displaying some waveform data.
I have a DAQCard-6036E card, and I am bringing in 16 analog signals. The task is set up through MAX, and right now is generic. All I am reading is random noise in an attempt to see if my VI even works. The acquisition mode is set to continuous, with a rate of 1k, and number of samples set to 100.
The problem is that I get very intermittent data on the front panel indicators. Only several of the indicators work, and its choppy at best. What am I doing wrong here? Is it a problem with my acquisition mode?
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Hi Alex,
I just tried the your VI with the while loops deleted out of the
subVI's and as far as I could see the indicators in the first two
columns of the front panel were updated as expected. The other
indicators are not wired so they will not update. It might look like
some of the wired indicators are not updating each time if the value
doesn't change - ie the potential on the line is the same as the last
read. You might try putting a known signal on each of your test lines
instead of using noise to test your system to verify that the voltage
is changing each time.
If you are still having trouble, post again. I've attached a copy of the VI I used for test.
Regards,
Micaela N
National Instruments
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Hello
Please take a look at this vi:
Attachments:
Real-Time Chart.vi ‏19 KB

Ben wrote:
It looks like you are getting bogus time stamps from the SV.
This thread talks about the chart and waveforms.
Try click the Chart on the front panle to find the ignore...
Ben
As far as I understood this example uses "t0" from the waveform data for x axis. I tried this method and it works. The date and time shows correctly. That's great.
But I actually have another request for the chart display, that is to show data in a certain time period, which should be programmable. For example I could let the chart show the data waveform in 10 seconds this time(I mean in one screen without scrollbar), and the next time I execute it, I change the parameter and show the data waveform in 60 seconds.
I tried to modify the initialization like that:
I thought by changing the maximum value of the scale range, I could realize that. This kind of setting didn't really work. before the breakpoint, the time in x axis became chaos again, and after going into the loop it returns to correct value.
Do you have any ideas how to realize that?
Thanks again!
Best regards
zzha

How to use ni-6008 and build a four channel data acquisition at a rate of 250 samples per channel and display all the data in a waveform chart

how to use ni-6008 and build a four channel data acquisition at a rate of 250 samples per channel and display all the data in a waveform chart

Hi kdm,
please stick in one thread for the same topic!
Best regards,
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I am trying to convert old data arrays in LabVIEW 4.x & 5.x to the new Waveform Data Type in LabVIEW 6i. Please Ref. Doc. LabVIEW 6.0 Upgrades Notes page 7-8 as a source.
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try to use Buil Waveform VI after loading old data from files ...
LabView Help : "Build Waveform
Builds a waveform or modifies an existing waveform. If you do not wire an input to waveform, Build Waveform creates a new waveform based on the components you enter. If you do wire an input in waveform, the waveform is modified based on the components you specify. This function is expandable."

How do I convert a earlier numeric array in LabVIEW 5.x or eralier to a Waveform Data Type in LabVIEW 6i?

I am trying to convert old arrays in LabVIEW 4.x and 5.x to the new Waveform Data Type in LabVIEW 6i. Please ref. Doc. LabVIEW 6.0 Upgrades Notes page 7-8 at a source of reference. Has anyone ever tried it?

Hi Andy,
I do this all of the time. On the block diagram palette is the Waveform subpalette. The second icon is the build waveform vi. This has three elements, to, dt, and y. The to is the initial time (typically zero), the dt is the delta time in your waveform and the y is where you wire up you old array data to. The output is a waveform datatype.
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Acquire, display, and write data at 50 samples per second

I have a vi running on a PXI which samples data using two 4220's (all 4 channels) and one 6031 (only 6channels). I am acquiring data at 100 samples per second, but only need to write the data out at 50 samples per second. The data needs to be displayed at a minimum of 10samples per second. The problem is that the VI can not get 50samples per second writen to the file, it writes about 20 to 30samples per second.
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Galen
Attachments:
ATM_FrictionTests_v1.2.vi ‏375 KB

Galen,
Looking at your vi, I would recommend writing to your file in a different way. The function you are using is actually opening, writing, and then closing the file every time you call it. This greatly increases the amount of resources being used. Take a look at the Cont Acq to Spreadsheet File.vi example and note that the file is only being opened and closed once. The data is being written to the file during execution of the program, and then closed when the app is done running. The example is done in traditional DAQ but you should be able to do something similar with DAQmx. Try this and let me know if it helps.
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How to display a waveform in XY format where X is the time in seconds?

I am aquiring voltage from a power sensor and I am displaying this voltage as a waveform in a waveform chart. Now, I would like to display this waveform such that on X axis I have a range from 0 to 30 seconds (X axis should be displayed in seconds of recording not actual time). On Y axis I would have the value of parameter I am aquiring of course.
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It is a data signal type that has timing info in it.
What I am actually trying to achieve is to display the data in a chart (that has seconds on X axis) only when I turn on a button. When I turn off the button the data should stop being displayed in the chart. Problem is that when I turn on the button again the new data displayed should flow from the point where old data stopped being displayed. In a chart having actual time on X axis this is not possible because the time will be different that the time when the data stopped being displayed so you will have a gap between the old and new trains of data. I want continuity and I was hoping to get this if I take the timing info out...
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Hi everyone, I'm new to labview. I have a question, how to obtain waveform data(an I/O file so I can plot it in graphic software), rather than just plot a waveform graph which is pretty easy, but I want a waveform data table, how can I do that? Thank you very much!
Message Edited by pack2themoon on 12-12-2008 10:05 PM

Well, I would tell you how to get the data to display on a table however then you will come to another issue.
The issue is that once the data is in a table, you cannot select all the data at once.
You can only select one cell at a time, I'm not sure why, guess it was an oversight of some kind.
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Cory K

Is it possible to display a waveform with fixed length and fixed starting point?

Hi,
I am using DAQ assitant to acquire voltage and current measurment of my device. The voltage is a pure sine wave and current is a periodic waveform with phase difference and distortion. I use waveform chart to display the waveform of voltage and current waveform in seperate charts and they work fine.But the waveforms look like moving to the right all the time, in another way ,the phase is always shifting. Now i want to display the waveforms of both with fixed length (say 2 cycle) and also in a same chart. Apart from that, i also want to display the voltage waveform starting form 0 degree (a fixed point )rather than moving all the time. In this case, i can observe the angle difference between voltage and current. Is there any method to achieve this purpose?
Many Thanks,
Hao

Hao,
first of all, you are using a chart which has three options for updates if the chart is "full":
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Scope chart
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Waveform chart time axis is not matching the waveform data

So here an interesting conundrum I hope you might be able to help me with...
My VI has waveform data sent to a chart, though the data is not being plotted against the current time. Rather, it is being plotted starting way back in the reference time (way back in 1903). I don't understand why this is happening. When I build the waveform, I use the "Get Date/Time in Seconds" function outside the while loop and feed that into my "Build Waveform" Function as the t0 value. My dt value is 0.05 (20 Hz) and then I feed in my array of data in the Y input. Any ideas why the chart is plotting this data over 100 years ago? Thanks!
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Hiii, Ronin
Here is your solution.
By default, waveform charts and graphs display the absolute time at time 0 as 7:00:00 PM, 12/31/1903 on a Windows based system. Property nodes can be used to get the correct absolute time to display on the x-axis of the waveform chart.
First, right click the chart on the front panel and select X Scale >> Formatting. Then set the format to Absolute Time.
Create a property node for the waveform chart by right-clicking on the chart on the block diagram and selecting Create >> Property Node. Expand the property node to display two properties. Select the Format property and the Offset property. The Format property is located under X-Scale >> Format and Precision >> Format, and the Offset property can be found under X-Scale >> Offset and Multiplier >> Offset. Right click on the property node and select Change All to Write.
For the Format property, the context help shows that there are multiple inputs to this property. Wire in a value of 7 to set the format to Time and Date.For the Offset property, first wire the output of the Get Data/Time in Seconds VI to the input of the To Double Precision Float VI. Then wire the output of the To Double Precision Float VI to the Offset property.
In addition, if you know the number of data points plotted to the chart per second, you can set the Multiplier property located under X-Scale >> Offset and Multiplier >> Multiplier. If there are x data points generated per second, wire in a value of 1/x to the Multiplier property. A simple example program "Chart with Timestamp" that demonstrates how to do that is attached.
Thanks,
Nishant
Attachments:
Chart with Timestamp.vi ‏36 KB

Help with Multi point chart plot hile using the waveform data type..

Currently I have two channels being transfered into the AI C-Scan block (by means of a build array) in hopes to display the outputs on a chart as well as an output file. As an outout I am using the waveform data type, as I hear this is the way to go. Problem is that I have the the Waveform chart directly connected to the waveform out put the the AI C-SCAN block but nothing is being displayed on the chart. Although the time is updated on the chart it is listed as the year 1903. I do have data these channels as the there are digital outputs for these channels. Perhaps I should use the AI CONFIG and AI READ clocks rather than this AI C-SCAN. Any ideas...

Christian,
Please see the Real-Time Chart shipping example for LabVIEW. This example describes how to set the base time of the chart so that the time and date are correct.
You may want to autoscale the Y-axis as your data may be out of range of your chart and that is why nothing is seen.
Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

Convert a TTL to RPM numeric display.

Hardware
cDAQ NI 9172
Module: NI 9401
Monarch Instrument’s Remote Optical Sensor (for measuring RPM/pulse counts)
Software
NI Sound & Vibration Assistant
NI Signal Express
LabView
Experience Level
Beginner
My objective is to read and record accelerometer and engine speed data together so they are time stamped the same. Setting the accelerometer up was easy… the RPM, not so easy.
I have been trying to convert a 5v TTL signal from an optical sensor, which is used to measure RPM, in NI Sound & Vibration Assistant. The optical sensor is a stand alone, self powered system with a output signal of “TTL compatible pulse (0 to 5VDC)”.
I’ve started a project in NI Sound & Vibration Assistant, “Add Step”, “Acquire Signal”, “Digital Input” and “Line Input”. On the Step Setup Tab/Configuration Tab, I’ve selected my channel, Acquisition Mode set to Continuous Samples, Rate set to 1.3kHz. Then on the Step Setup Tab/Advanced Timing I had to select “On Demand” for Sample Clock Type due to error message(s). “On Demand” is the only way to get the signal to appear on the Step Setup Tab’s graph. The signal is a square wave represented by 0 and 1 (0s and 1s are overlaid on the graph). When I block the optical sensor view, the signal goes flat represented by 1.
I’ve also messed around “Acquire Signal”, “Counter Input” and “Edge Count” with the same results.
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Thank you in advance for any help.

Ferzo,
Great example! I am able to get a RPM numerical value… however when my rotating component slows to a stop, the processed data (logging) stops updating around 500 RPM. I was expecting the value to drop to zero as my source reached zero. Plus some of my speeds, that I need to measure, can be a low as 1 to 100 RPM.
Please note that your screen shot of the formula page is different than mine. Mine is missing the “Input and Output Scalars” window… any ideas?
Thanks,
Team Stoney
Attachments:
RPM Ending.ppt ‏257 KB
RPM Formula Step .ppt ‏152 KB
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***What is your favorite VI or other software to view large sets of waveform data?

What is your favorite VI or other software to view large sets of
waveform data?
I have to look at waveforms with several sets of y data of 10000 or so
points. Should I put this into Excel? There are no cursors, or zoom
capabilities, and so on in Excel.
Using a graph in LV is very slow when loaded down with this much data.
Frankly a scope is easier for viewing waveforms. A scopelike utility
for Windows?
MathCAD?
Is there any neat shareware out there?
Thanks for your opinion,
Mike

There are a large number of analysis packages on the market that can display very large datasets. The one to choose depends largely on the nature of the data and what you want to do with it after you have loaded it in. Wandering down the software aisle at your local Staples you will find at least two or three.
With datsets the size you are contemplating, a major feature to look for is a zoom function that initially shows the entire waveform but lets you narrow in on the data you want to see.
DIGRESSION ALERT
Actually, this sort of algorithm isn't to hard to code. I wrote a viewer once that allowed you to view datasets of arbitrarily large size (in V3 I think... though it may have been in V4). The code initally presented an overview of the entire dataset
by decimating it down to a size that LV could display rapidly. As the user zoomed in using the cursors (not LV's graph zoom) the code would extract the selected portion of the data, redecimate it if necessary and redraw the display. (Which by the way is all the fancy packages really do anyway.)
The tricky part is selecting a decimation function that retains the overall shape of the data.
ENDOF DIGRESSION
Several years ago I wrote an article for a magazine (Personal Engineering and Instrumentation News) that dealt with graphing packages that could handle a million datapoints at that time (late eighties) there were over a dozen programs--and they were all better than Excel...
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
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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

TO Display the row data as column in ALV

Hi experts ,
Need to display the row data in ALV as column.
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How can this can be achieved?

Hi,
Actually it is not possible to disaply in multiple lines.
https://www.sdn.sap.com/sdn/collaboration.sdn?contenttype=url&content=https%3A//forums.sdn.sap.com/thread.jspa%3FforumID%3D50%26threadID%3D49517%26messageID%3D506378%23506378
https://www.sdn.sap.com/sdn/collaboration.sdn?contenttype=url&content=https%3A//forums.sdn.sap.com/thread.jspa%3FforumID%3D50%26threadID%3D41133%26messageID%3D403371%23403371
This problem was discussed many times in this forum, u can search for more results.

Realtime numeric display of waveform data in SE

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