Pause scanning for AI Acquire waveform...

Hi... i'm using labVIEW 7.1...
I'm also playing a DAQ hardware now... i using it to read signals in real time through AI Acquire Waveform....
what i wanna ask is "possible to pause the AI Acquire Waveform by clicking a button"?

Hello Jaxx!
There is no way to change the code generated by the DAQ Assistant to become a Traditional DAQ function. However, we can apply the same concepts that we talked about earlier to get the same functionality in Traditional DAQ that we had using DAQmx. The easiest way to accomplish this is to get an example of a finite analog acquisition using the Traditional DAQ driver. There should be plenty of these examples in LabVIEW that can be found in "C:\Program Files\National Instruments\LabVIEW 7.1\examples\daq\anlogin" or by using the NI Example Finder in LabVIEW. Then, you could be all of this code inside of a case structure that is controlled by a button on the front panel. A while loop would then be placed around the case structure so that the program will run until the user stops it completely.
Hope this helps,
E.Lee
Eric
DE For Life!

Similar Messages

How to make AI acquire Waveform stop scanning...

Hi... i'm using labview 7.1 and playing a DAQ hardware now...
i wish to know how to make the "AI Acquire Waveform" stop scanning data into waveform, i heard someone said that got a build in fuction to stop it... can anyone tell me is it true? If no, can let me know the method to stop it?
with regard
Jaxx

If you want to pause your acquisition then the best thing to use would be Pause Triggering (DAQmx) or Scan Clock Gating (Traditional DAQ). You can find examples for either one in the NI Example Finder, search for 'pause' and go to the Cont Acq&Chart Samples-Int Clk-Pause Trigger.vi (DAQmx), or you can search for 'digital scan clock gating' in the search field for ni.com.
You may also want to look at this site for more information on triggering concepts: http://zone.ni.com/devzone%5Cconceptd.nsf/webmain/2A03115556FB233386256870005BB522
In your original comment you stated you simply want a pulse on one line to start, and then to pause the acquisition on the next, then repeat the operation. You may just need to use the Start and Stop Trigger examples reinitialize your task if this is the case where you are just looking at a pulse on one line. Pause triggering or Scan Clock Gating will relate more to you having a single line go high and staying high until you want to pause the acquisition.
Particularly if you are in the situation where you have pulses coming in on a single line I would recommend you look at the DAQmx examples rather than the Traditional DAQ examples. The architecture of the code is more efficient and will allow you to more quickly reinitialize the task.
Otis
Training and Certification
Product Support Engineer
National Instruments

How to use AI acquire waveform.vi for continuous acquisition

Hello all,
I am using LabVIEW 5.1 and PCI-6023E to acquire a voltage signal continuously, display the acquired data on a chart(display one minute of data at a time)then save all the acquired data to a spreadsheet file.
When I used the random number as a signal to develop my program; everything has worked as expected. However,it is not working now as I replace the random number with a real voltage signal using the AI Acquire Waveform.vi. I have encounterd several problems:
1/ Only display one second of data at a time.
2/ The elapse time that I have calculated does not match with the time display on the chart.
3/ The program runs very very slow when I increase the number of scans
to acquire to 1000, but my program need to acquire the signal for 15 minutes at a rate of 50Hz(50sample/second); it is about 50,000.00 samples.
Do you have any idea how should I do to make it works? I am a novice in LabVIEW; any help would be greatly appriciate.
Hao
P.S: I've attached my program if you want to take a look at them.
Attachments:
Acquire_Using_Random_Number.vi ‏89 KB
Continuous_Acquire.vi ‏96 KB

Helleo Labviewguru,
Yes, I did tried to see those examples but I could not display on a chart nor store to an array and save to a spreadsheet file when I used the AI Config.vi, AI Start.vi and the AI Read.vi(in a while loop). Can you please help me with this.
Thank you in advance.
Hao

AI acquire waveform. maximum readable data

Hello,
For acquiring data from an DC-accelerometer I'm using the 'AI acquire
waveform.VI' to perform this task. I'm scanning for 10 seconds at a sampling
rate of 10.000 S/s. When I'm looking at the amplitude spectrum I find
spectral components below 1 Hz which can't physically be there. (10 seconds,
so df = 0.1 Hz). Is it possible that this has got to do with the acquiring
technique??
Thanx,
Ron@ld

To expand on the previos response, Nyquist Thereom tells us we need to sample at least twice as fast as the signal's frequency to get an accurate sampling and reduce aliasing effects. Aliasing can also be due to noise sources in the environment so using a low-pass filter is still a good idea. Here is a Knowledge Base on aliasing and low-pass filtering:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/68f14e8e26b3d101862569350069e0b9?OpenDocument

Can I acquire waveform at faster sampling rate using external clock?

I am trying to acquire waveform at a sampling rate of 1MHz. My 6036E card is maxed out at 200KHz. Is there a way to achieve a sampling rate of 1MHz using an external sample clock? Your PFI pin can take external clock as an AI sample clock, right?

Hi,
I remember I asked the similar question before in the NI forum, they reply me:
the max sample rate (scan/s/channel) cannot be greater than your board max sample rate, even you use external scan clcok. So the answer is no for your case.

Problems using acquire waveform...

We are trying to read an accelerometer signal using AI Acquire Waveform(it didn't work with similar boxes either).
The problem is that we set a scan rate of say: 10k samples/s and number of samples of 10k.
So every second the buffer is refreshed(so we can see the graph) and there is a big distortion.
Distortion is always the lenght of the buffer. We could do a "blind" acquisition setting a big buffer(# of samples). That would solve the problem but it shouldn't be like that.
Thanks,
Erick

Could you explain a little more what the distortion you see looks like?
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... 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

SEVERE: An error occured while scanning for the next trigger to fire

Hi All,
I followed below steps to configure Oracle BI publisher scheduler on oracle 10g database.
1.Log in to BI Publisher as a user with Administrator privileges and select the Admin tab.
2.Under System Maintenance, select Scheduler Configuration.
3.Enter the database connection information for the target Oracle database and user.
Database Type: 10g
Connection String: jdbc:oracle:thin://<hostname>:<port#>:<oracle SID>
Username/Password for the database user
Database Driver Class: oracle.jdbc.driver.OracleDriver
4.Click the Test Connection button to make sure the connection information is valid.
5.Click the Install Schema button to install the scheduler tables.
6.Restart the BI Publisher application.
The Schema installed successfully.
But when I am starting the weblogic server I am getting below error and BI publisher application is not getting up.
INFO: Handling 6 triggers that missed their scheduled fire-time.
23-Dec-2011 05:29:38 org.quartz.core.ErrorLogger schedulerError
SEVERE: An error occured while scanning for the next trigger to fire.
org.quartz.JobPersistenceException: Couldn't acquire next trigger: Couldn't retrieve trigger: Invalid column name [See nested exception: org.quartz.JobPersistenceException: Couldn't retrieve trigger: Invalid column name [See nested exception: java.sql.SQLException: Invalid column name]]
at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:1773)
at org.quartz.impl.jdbcjobstore.JobStoreTX.acquireNextTrigger(JobStoreTX.java:1176)
at org.quartz.core.QuartzSchedulerThread.run(QuartzSchedulerThread.java:233)
* Nested Exception (Underlying Cause) ---------------
org.quartz.JobPersistenceException: Couldn't retrieve trigger: Invalid column name [See nested exception: java.sql.SQLException: Invalid column name]
at org.quartz.impl.jdbcjobstore.JobStoreSupport.retrieveTrigger(JobStoreSupport.java:1126)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:1759)
at org.quartz.impl.jdbcjobstore.JobStoreTX.acquireNextTrigger(JobStoreTX.java:1176)
at org.quartz.core.QuartzSchedulerThread.run(QuartzSchedulerThread.java:233)
* Nested Exception (Underlying Cause) ---------------
java.sql.SQLException: Invalid column name
at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70)
at oracle.jdbc.driver.DatabaseError.newSQLException(DatabaseError.java:133)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:199)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:263)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:271)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:445)
at oracle.jdbc.driver.OracleStatement.getColumnIndex(OracleStatement.java:3372)
at oracle.jdbc.driver.OracleResultSetImpl.findColumn(OracleResultSetImpl.java:2009)
at oracle.jdbc.driver.OracleResultSet.getBinaryStream(OracleResultSet.java:668)
at org.apache.commons.dbcp.DelegatingResultSet.getBinaryStream(DelegatingResultSet.java:233)
at org.quartz.impl.jdbcjobstore.oracle.OracleDelegate.getObjectFromBlob(OracleDelegate.java:154)
at org.quartz.impl.jdbcjobstore.StdJDBCDelegate.selectTrigger(StdJDBCDelegate.java:2382)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.retrieveTrigger(JobStoreSupport.java:1115)
at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:1759)
at org.quartz.impl.jdbcjobstore.JobStoreTX.acquireNextTrigger(JobStoreTX.java:1176)
at org.quartz.core.QuartzSchedulerThread.run(QuartzSchedulerThread.java:233)
23-Dec-2011 05:30:55 org.quartz.core.ErrorLogger schedulerError
The system details are as below :
BI Publisher version : 10.1.3.4
Oracle DB : 10 G
Weblogic server :10.3.2
Please suggest to resolve this issue.
Thanks,
Sachin

Hi,
This errors occurs if you have configured some schema for the scheduler and configured it on BIP, but the configured schema is no longer available.
That is why I am suggesting you to replace the current quartz.properties file with the original file that exits during installation.
Then try to start the server, and see if the server starts without error.
After that you can try to configure the scheduler from BIP console.
thanks,
sandeep

Error 10401 occurred at AI Hardware Config, when using AI Acquire Waveform vi

I can successfully run applications that use the AI Sample Channel vi, however when I use the AI Acquire Waveform vi the following errors are generated:-
Error -10401 occurred at AI Hardware Config, followed by
Error -10401 occurred at AI SingleScan.
All applications have been developed using Labview 6.0.2, on an NT machine. The applications are then run (or atleast attempted to be run) using the Labview Run-Time Engine on a different NT machine.
The driver software I am using is the NI-DAQ Native Data Acquisition Driver Software Version 6.1.

Hi,
I've found a Knowledge Base on the NI website describing some situations where this problem occurs:
http://digital.ni.com/public.nsf/websearch/46F78EDD19BA0CC386256CEE007201FC?OpenDocument
That error code is generally seen when something has changed in the DAQ card's configuration, or the drivers are not installed properly. It's strange that this is showing up only on certain functions for your application.
Also try having a look through the DAQ troubleshooting pages on the website:
http://www.ni.com/support/daq/
Regards,
Mark Lee
National Instruments

AI Acquire Waveforms High and Low Limit

Hey everybody,
I am currently working with Labview 7.1 and a daq card. I am collecting 4 channels and using ai acquire waveforms to do this. I want to have different high and low voltage limits for each channel though. Is there a way to do this with ai acquire waveforms or would can I use something else.
Thanks for the help!
Devon

Hey Devon,
In addition to what David said, there is a great knowledgebase article here with more information about setting multiple ranges for Analog Input. The Traditional DAQ vi, AI Acquire Waveforms, doesn't expose the ability to set multle input ranges per channel, but there is a quick fix that you can do to be able to add it to the vi. See below:
The block diagram of the AI Acquire waveforms is as follows:
As you can see, the inputs of the vi that are exposed are simply the first element in a array of clusters including the high and low limits per channel. To set the high and low limits for other channels, you need to simply add another element to the array for channels 1, 2, and 3. See below:
Here you can see I simply added one element, you need to add 2 more for your 4 channels. If it turns out that you are using DAQmx and this doesn't apply, please refer to the knowledgebase above for details and an examples on how to set different ranges.
Regards,
Paul C.

Ai acquire waveform.vi

Hi,
Recently I receive a code from my senior to read data from DAQ bnc-2090. I have installed DAQmx 9.3 but I cannot run the code due to "cannot load ai acquire waveform.vi." I have find the answers that an old version of DAQ driver is needed. However, TDAQ driver is only suitable for Windows XP/2000, and I use Windows 7. What should I do to solve this problem? Thank you.

The only driver for that card is traditional DAQ and you've already found out that it is not supported on Windows 7 so why this question?

AI acquire waveform

For my project, I am using a last year student's VI as reference, but when loading it up, it asks for a "AI Acquire Waveform.VI" which I cannot be found, and there is no "data acquisition" tab under which it is normally found according to the manual, why is this?

Hi AV34,
What versions of LabVIEW/DAQ do you have installed?
If you installed DAQmx 8.0 then the traditional drivers (NI-DAQ) would not have been installed.
You need to install DAQ 7.4.1 or earlier onto your computer to get the traditional DAQ vi's.
They can be found at the following address:
http://digital.ni.com/softlib.nsf/websearch/3dbf3d343476a28f8625709e006a4937
All that said and done.. What aquisition device are you using? (DAQmx might be the beter way to go)
Many Thanx
AdamB
Applications Engineering Team Leader | National Instruments | UK & Ireland

A question about "AI acquire waveform.vi ".

I use my DAQcard(PCI-6024E) to acquire two AI signal at the same time through AI acquire waveform.vi.
But it is getting into a serious delay on my executing progarm by monitoring my time depended plot or time-counter(It is about 5 seconds in the real world vs. 1 second the program runs.).
however,I didn't encounter that problem when altering another AI vi(AI sample channel.vi),but it couldn't conform to my needs.
My AI acquisition program structure is "AI acquire waveform+equi-Ripple lowpass+mean" and another is "AI acquire waveform+mean".All settings are default except the high and low limit.So,does anyone solve my troubles?I really need help!!
(The situation is Labview 5.1 in the PC of p-133,32MB,and more than 1G reserv
ed capacity for C
thanks a lot!

Hello;
The best way to go about that is to use the Labview shipping example named Continuous Acquisition and Chart (buffered).vi that you can find at Search Examples->I/O Interfaces->Data Acquisition->Analog Input->Continuous Analog Input; as the start point for your development.
That vi shows the best way to do a data acquisition. You can insert you average VI inside the while loop of that VI.
Hope this helps.
Filipe A.
Applications Engineer
National Instruments

AI acquire waveform. vi update rate

Hello,
I would like to increase the update rate ( which governs how many samples are acquired per second) for the attached vi- AI Acquire Waveform(waveform).vi.
This vi is a built in vi obtainable from Analog Input palette under Measurement I/O.
The update rate preset is 1000 samples per second, i want it to be 10,000 per second.
If i type it manually, it doesnt stay and reverts back to 1000.
I am using LABVIEW 8.6 on Windows XP machine
Thank you very much and Regards
poli
Solved!
Go to Solution.
Attachments:
AI Acquire Waveform (waveform).vi ‏14 KB

Hi Poli
Have you looked at the the daq examples. Labview is shipped with a lot of examples. Also are you running this by using the continuous run button? That button is for debugging only, and it is a no-no to use it for other purposes
If you are new to Labview perhaps some of the online basic lessons will do you good.
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

Can I force LE 8 to scan for audio device?

I run all recordings through a Mac Min. As there is only 1 firewire port, I need to have my mixer feeding into a powered hub. When I start the Mac, it doesn't retain the connection to the mixer and I need to switch the mixer and the mic off on order to let Logic go through the scanning process to re-acquire it. This isn't really a problem, but I find it really irritating. When I had a direct firewire connection to the control room iMac, it always 'saw' the mixer and mic.
Can anybody suggest a way to keep the connection/setting or can I force Logic to do the scan for audio devices without having to turn the mixer off and on.
Thanks.

I am aware of the "hold alt key" at start up. However this doesn't work for me for some reason

How can I find an example about acquiring waveform data by software trigger using PXI 4070 DMM?

Anybody could proivde an example or simliar about acquiring waveform data by software trigger using PXI 4070 DMM?
Thanks!

hi there
from the NI main page go to the developer zone http://www.ni.com/devzone/dev_exchange/ex_search.htm. select "LabVIEW" and "Digital Multimeter (DMM)" and search for "4070". then you'll find some examples.
Best regards
chris
CL(A)Dly bending G-Force with LabVIEW
famous last words: "oh my god, it is full of stars!"

Pause scanning for AI Acquire waveform...

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