Acquire waveforms from function generator to oscilloscope

I have a problem. We constructed a virtual function generator and a virtual oscilloscope. It's working well, the oscilloscope is displaying the (almost) correct data. My problem is that the waveform displayed in the oscilloscope vi is always sine, although the selected waveform in the function generator is already different.
I should replace the constant 'zero' with something so that the cases will change in order for my oscilloscope to display different waveforms. Is there a way to acquire the values of the constant enum, for instance, from another vi to this vi?

Yes, you would need to replace the constant with a control. Once you do this, in the main VI you simply do a right click on the subVI's terminal and select Create Control/Constant that but you cannot change it as the subVI runs.

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Error in acquiring waveform from the agilent 54621A oscilloscope .

error 1074003951 occurs when acquiring waveform from the agilent 54621A oscilloscope.
I have installed
agilent 546xx series instrument driver
NI VISA 14.0

The *IDN command is sent and i have chequed the VISA read it returns the correct string .The error still exists i have attached the block program
Attachments:
AGILENT 54621A Acquire Waveform.vi ‏16 KB

How to trigger an analog waveform from a generated waveform

Hello all,
I have an analog waveform via DAQmx and I have created waveform shape and amplitude limits by using generated square waveforms. I am having trouble aligning these waveforms so that I can test the shape and assure that it is within my limits.
Thanks

There really isn't any method for aligning an acquired signal and a generated signal. I looked into "Align Waveforms (Continuous).vi", but it doesn't appear to work with Square Waves.
http://zone.ni.com/devzone/cda/epd/p/id/5800
One method you could do is manually align the squre waves by adjusting the phase of the "Square Wave.vi". From what I understand, that won't work for your testing since it will require interaction. What parameters of the wave are you trying to measure and test? Just the amplitudes? Frequency too?
I hope this helps.
-Nathan
Product Support Engineer
National Instruments

Sending waveform to function generator?

Hello all,
I am using an agilent 33205A function generator and require it to use a
special driving waveform. Currently I load the waveform using
this HP Benchlink software. I would like to automate this in the
startup of my vi. Is there a way to download a "home-grown"
waveform to the function generator using labview?
Thanks,
Azazal
Azazel
Pentium 4, 3.6GHz, 2 GB Ram, Labview 8.5, Windows XP, PXI-5122, PCI-6259, PCI-6115

If you're using the driver from here, then use the function called ag33xxx - Arbitrary Wfm Ops. You will have to create the waveform in the form of a 1D array. Look at the high level example called ag33xxx - Arb - Application. I don't see a function in the driver that allows you to output a defined waveform so you may want to look in the instrument manual to see if there is such a function. If there is, then it should be a simple matter to read it and then place the values into LabVIEW as a constant or something you read from file.

Elvis: Is It possible to use the Function Generator and the Oscilloscope simultaneously?

Hi,
We are using the NI Elvis to output a function or a sine wave at a certain frequency and using the oscilloscope on the same board/elvis to read a modified signal. Is this possible? Can we use both the Function Generator and the oscilloscope at the same time? Please help. The oscilloscope would be reading signal from an accelerometer. Thank you in advance. We have no VI as we do not know which to use and if they are possible.

Hi,
There is no problem using the Function Generator and Oscilloscope
at the same time with NI ELVIS. Using the NI ELVIS soft front panels (Start
>> Programs >> National Instruments >> NI ELVIS 3.0 >>
NI ELVIS – see picture attached –‘NI ELVIS soft front panels.JPG’), you can choose
to open more than one instrument at a time. We do this by opening one
instrument, allowing it to begin, and then opening another. We can also program
in LabVIEW using more than one instrument at a time by placing down multiple
Express VI’s taken from the NI ELVIS pallet on the block diagram (see picture
attached – ‘ELVIS Express VI's (LabVIEW).JPG’). One note when doing this,
please see KB 41ODPHX1
for an example of how to program in parallel. If you do not wire the ‘stop’
terminal of the express VI’s, you will get the error described.
David L.
Systems Engineering
National Instruments
Attachments:
ELVIS Express VI's (LabVIEW).JPG ‏74 KB
NI ELVIS soft front panels.JPG ‏56 KB

Derivate a waveform from a Function generator

I want to use the derivate of a waveform from a Function generator in a Formula node, but unfortunatelly I dont no how can i do this. I need the exact value of the derivate ("qpg" input variable) to use in the equation in the Formula Node.
I found a Derivate sub VI, but it gives me the derivate as a vector so i cant wire it as an input to the Formula node.
I attached pictures about my VI.

As I understand it, you are using a Waveform Generator VI, and want (in addition to the Waveform) an additional output that is (an estimate of) the derivative of the Waveform.
If you consider the Waveform Generator as a "black box", something whose internals you don't know, but something that produces a new output every delta-t time increment (I'm going to call this "dt"), then you really do need to estimate the derivative. Note that since you cannot "predict the future", to estimate the derivative, you need the current data and previous data. One very common estimate for the derivative x'(t) at time t is (x(t) - x(t-dt))/dt, that is, the difference between the current point and the previous point, divided by the time increment. For a waveform generator, this will probably be a pretty good estimate, as the data should be relatively "smooth" and noise-free. Do note, however, that this estimate is really over the time interval t-dt and t, so you could consider it shifted backward in time by dt/2.
If you want a more accurate estimate of the derivative, one "centered" on the current time, t, then your formula needs to take into account not only the current value and past values but also future values. This is the reason many "derivative functions" use vectors, as this contains past and present values (with some worry about what to do at the beginning and end of the data).
On the other hand, if you are generating the data yourself (that is, if you have a VI that you input t and it outputs f(t)) and you have a "nice" function f (say a sinusoid or other non-random function), you can get the "exact" derivative just by programming it. For example, if f(t) = sin (omega * t), then f'(t) = omega * cos (omega * t).
Bob Schor

How to acquire reference waveforms from Tektronix oscilloscopes

Hi,
I want to acquire stored waveforms .wfm from oscilloscope to LabVIEW for analysis purpose.I tried by using Tek scope drivers,but gives error. what is the appropriate way to do it. Plz help...
Thanks in advance.
sayaf.

Use Tektronics Programer Manual. Find All GPIB commands and there find what command to acquire waveforms. Usually, you write GPIB command and read response from Tek.

Acquiring a waveform from the input channel

Hi, while I am trying to acquire teh waveform from the input channel,
it is not showing up in Labview "waveform graph", but the same
waveform is seen on the oscilloscope. I am using NI PCI 6052-E DAQ
board.

Greetings Amu,
How have you configured the PCI-6025E? Is it configured for
differential readings or single-ended readings?
By default, the configuration of the device will be differential,
which means that two input channels are used for every input signal.
When configured in differential mode, you need to connect the positive
terminal of the signal to channel X and the negative terminal of the
signal to channel X+8. For reading a differential signal from channel
0, you will connect the positive terminal of the signal to channel 0
(pin 68) and the negative terminal of the signal to channel 8 (pin
34).
I would suggest to use the Measurement and Automation Explorer (MAX)
software to test the signal before going to LabVIEW. Open MAX and go
to the devices and i
nterfaces folder. The PCI-6052E should be located
in this folder. Right-click on the PCI-6052E and select test panels
and you will be able to test the input signal here. You can change
the mode to continuous and set an sampling rate in the test panels as
well.
Once you can view the signal in the test panel of MAX then I would
suggest to move to LabVIEW. Search for the shipping example entitled
'Cont Acq&Chart (buffered) VI' which is a continuous analog input
example. Select the device number, channel number, and scan rate and
run the VI.
For more information on connecting your signals to the PCI-6052E I
would suggest to refer to chapter 4 of the user manual. I've linked
it below for your reference.
NI 6052E User Manual
http://digital.ni.com/manuals.nsf/webAdvsearch/552436964E347DAF86256BDE00670E9B?OpenDocument&vid=niwc&node=132100_US
I hope this helps.
Let me know if you have any additional questions regarding this issue.
Regards,
Todd D.
NI Applications Engineer

Generate and acquire signals from Walkie Talkies

Hello, i am a Portuguese Student and i have some problems in a Academic Project.
The following project consists in two Walkie Talkies that are link to a USB 6009.
One of the Walkie talkies are attached do AO0 and ground with the objective of generate a signal to the 6009 then the other Walkie talkie connected to Ai0 and GND have to acquire the same signal that i generate in the other one, this two signals have the main problem that needs to be represented in the same Chart or Graf.
Please can anyone help me in this question and send me a (vi), i would greatly appreciate.
something send me a post or email for [email protected]

Hello Lynn,
Sorry about the late response, but only today i have access again to the USB 6009 in the LAB.
In below are the graph from the input signal, the first is the graph from the Walkie Talkie (receiver) when the button from the Walkie Talkie that send the signal are not press. What we see is only noise and others frequency's.
In the other graph we can see a different graph this graph is from the Walkie Talkie (receiver) but when the button from the Walkie Talkie that send the signal are press where we can see that is a different kind of signal and the receiver are ready to receive the signal and are receiving some signal from the other walkie talkie.
First I need some help for this first steps
1- But how can I generate a signal wave and send it from the other Walkie Talkie (transmitter), I used a Basic Function Generator
2-How can I see in the Walkie Talkie (receiver) if he receive the Signal that I generate in the transmitter, The graph changes of frequency and amplitude always that I press the button of the transmitter Walkie Talkie.
3-How can I put the two signals in the same chart or graph, The main problem is like you said the USB 6009 is too low sending signals.
Sorry my English, I appreciate any help
Thanks
BTP
Attachments:
input data.png ‏33 KB
input receber.png ‏37 KB

I want to use the Function Generator VI to send command signals through the NI 7344 motion controller. This will be a closed loop servo valve system. I want to be able to change from say a square wave to a sine wave on the fly. Idea's?

I am going to run tests that require an actuator to move using various types of arbitrary waveforms such as sine or square. The NI 7344 is hooked to the UMI that is going through a driver for a servo valve. The loop is analog and it is closed. I have played with some of the examples but can't get it to work. I have used the function generator VI to generate a signal but I think I am using the wrong input VI to the motion control board. When I use what I have it moves the servo and then stops. It doesn't continually generate the signal.
I would love to use the controls on the function generator vi to control frequency and amplitude ect. Any help or pointer would be helpful. Thank you in advance.

Hello,
I'm not clear on exactly how you want to use the generated data but I'm assuming they will be used as your target points.
There's a built-in example for motion called 'One-Axis Contour Move.vi'. This example demonstrates how to provide your target points as 1-D array. All you need to do is to replace the input array with the output of the function generator. In order to have it run continuously, use a while loop. You can further program your application so that it'll change the waveform on the fly by monitoring the user interface but this might be little little tricky as you will need to reset the move and load the new generated points while keeping track of your current position.
I hope this helps. Let me know if you have further questions regarding this
application.
Best regards,
Yusuf C.
Applications Engineering
National Instruments

How to read data from a GPIB when sending a function generator command

I'm using Visual C++ with the ComponentWork ActiveX and I'm tring to plot a
CWGraph using the data coming from a GPIB device. When I write command such
as "*IDN?" to the GPIB device, everythings if fine and I can read what the
GPIB device return me. But when I send a command like "SOUR:FUNC SIN;SENS
DATA?", the writing seems to be okay, but when I try to read the data, I
alway get a "Timeout expired before operation completed" error message. I
have tried with the CWGPIB and with the CWVISA but the result are the same
with both.
My reading code looks like this:
COleVariant vReadBuffer;
vReadBuffer = m_VISA.Read( COleVariant( (short) 2000 ) );
and it work fi
ne for "*IDN?" or for multimeters command.
I want to know how I must read the data for function generator commands.
Thank alot

It sounds like your device is not accepting that command string as valid. The string you listed above is probably missing a colon between SENS and DATA. "SOUR:FUNC SIN;SENSATA" Try sending this string in Measurement & Automation Explorer to the instrument first to make sure it is working.
Best Regards,
Chris Matthews
Measurement Studio Support Manager

How to plot data from a GPIB function generator

I am doing a litle application with Visual C++ and the ComponentWorks++ to
control a GPIB device. I am tring to Plot a CNiGraph with data coming from
the GPIB function generator. I use the code below to write/read the device
and to Plot the graph. It give me some results but for exemple, if I
request a sin wave it give me something that doesn't look like a sin and if
I request a square wave it give me about the same wave... So I want to know
if the problem is in my code or maybe it's because my device is just a
emulator not a real func generator. But I guest I am doing some kind of
convertion error.
CNiInt16Vector vBuffer(100); // Should I try CNiReal64Vector or something
else ?
m_Visa->Write(m_strC
ommande); // Write to the device, this works well
m_Visa->Read(vBuffer); // Is it the right way to do reading ?
m_Graph.PlotY(vBuffer); // This Plot some data, but it doesn't seem right
Could somebody bring the light on this?
Thanks alot!
P.S. Sorry for the bad english...

Ares:
I have two suggestions about common problems in VISA.
(1) How is m_Visa defined? There is occasionally some confusion about which VISA class should be used for this purpose. CNiVisaSession is the class designed for this purpose.
(2) How is the instrument returning data? Usually instruments return some sort of header before the actual data.
You may want to contact National Instruments Technical Support to continue this discussion. You can reach our telephone support at 1-800-IEEE-488 or email support at http://www.ni.com/ask.
Good Luck,
Chris Wood
Applications Engineer
National Instruments

I generated web service from function module.Where can I find .wsdl file ?

Hi,
I generated web service from function module.
Where can I find .wsdl file ?
I want to use .wsdl file in .Net application.
Thanks.

Hii Cemil Bozlagan,
All Remote enabled Function Modules in Web AS 6.20 and Above are available as Webservices and the WSDL documents are available in the web service repository at
[http://<host>:<port>/sap/bc/bsp/sap/webservicebrowser/search.html]
Find the respective BAPI.
Click on the WSDL link in the browser and download the WSDL document and use it as per the requirement
Regards,
Varun

Acquire data from oscilloscope DPO2024

I am trying to acquire data from oscilloscope DPO2024 using labview. I am able to do so, but my vi file works only for channel 1. Other than channel 1, it do not work and instead, it changes the setting of oscilloscope as well. Find the vi files attached.
Any help is much appreciated.
Solved!
Go to Solution.
Attachments:
data_acquire_oscilloscope1.vi ‏28 KB

1. You only need to initialize the scope once. You not need to branch the VISA Resource wire. Call the Initialize, Setup Channel 1, and then Setup Channel 2 all chained together.
2. Use Build Array to create your array of channels. The Merge Signals is a completely backwards way to do it.
3. You only need to close the instrument once.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions

Generate waveform from datafile

Hi all,
I have a datafile with the time and amplitude values of a human gait cycle. I want to generate a waveform from that file. Is there any method that read the data from the file and generate a waveform from that?
Pleae reply urgently
Jinal..

This is the file. If possibl could you please provide me coding also? I am a novice at Labview.
Thanks
Jinal.
Attachments:
Gait Cycle.xls ‏27 KB

Acquire waveforms from function generator to oscilloscope

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