Ripple Measurement using USB 5132

Hello,
I am trying to use NI USB 5132 to measure ripple (Vp-p) at the output of a DC power supply.
I not familiar with digitizers and having problems using the NI-Scope functions to create a VI that can measure ripple.
I have looked the example VIs, but not sure how to change the settings on the Vertical and Horizantal functions so that they work for me.
An help or inputs on this matter will be greatly appreciated.
Thanks.

The examples are as I recall pretty complete. What is the exact issue you are having?
Mike ...
Certified Professional Instructor
Certified LabVIEW Architect
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"... after all, He's not a tame lion..."
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Similar Messages

Changing temperature measurements using USB 9211

I am using a USB-9211 to record 3 temperatures that are all connected to a waterbath that is set at 21C. The recorded temps vary over time more than a degree or 2 each way with no apparent pattern. There doesn't seem to be any reason for this. The water bath is calibrated and is accurate to +-.01C. I tried using an ice bath with the same results. Do you have any idea what could be causing this variation?
Thanks,

Hey MEY,
Have you consulted the user guide and specifications for the 9211 on our website? Figures 9 through 13 demonstrate the error in degrees celsius for all the different types of thermocouples. The user guide is available here: http://www.ni.com/pdf/manuals/371566c.pdf
What kind of thermocouple are you using?
Elijah Kerry
Senior Product Manager, LabVIEW
Follow my Software Engineering for LabVIEW Blog

USB-5132 as gated integrator?

Greetings,
Can I use USB-5132 as a gated integrator?
I have a PMT signal with 1-10 kHz rep. rate. The signal itself lasts 2 us and I would like to slice this 2 us window into smaller bins and collect data in that specific window and integrate the signal.
I checked the manual, it looks like it does not have a built-in gated trigger mode. I am wondering if there is any wy around it...
Best regards
O.Birer

My problem is I could not figure out a way to sample the waveform within a gate. Can I use the rising edge to start acquisition and the falling edge to stop the acquisition?
(This is generic for all digitizers, not exclusive toe the 513x devices.)
Because digitizers/oscilloscopes take as granted that the window of time for which you wish to acquire is known at the time of the beginning of the acquisition, you cannot configure it to have a variable window size on-the-fly (without software intervention to stop and reconfigure.) This isn't done on the fly on any oscilloscope product I've ever heard of, from any vendor. In other words, the concept of "gating" an acquisition is not a concept natively handled by digitizers/oscilloscopes.
Work-arounds:
If you choose the largest possible gate time and set that to be your record length, then you can post-apply software to trim the data you don't care about.
If you can allow software/driver interaction with the instrument while your signal is generating, you can stop, reconfigure for a different record length, and re-start the instrument's acquisition again. Expect this could take a few milliseconds or more, depending on how you implement it.
In essence, I would like to time resolve the signal which lasts for 2 microseconds.
Is your signal repetitive? I can only imagine that acquiring several ~500ns windows of data with relative adjustments must mean your signal is repetitive.
Just for reference, see the Acquisition Engine for the USB-513x devices. You can see you will really only have two signals to work with to manipulate this device in hardware time: there is a start trigger (must be digital) and a reference trigger (can be analog or digital). You can send a "start" trigger or a "reference" trigger only to capture the constant amount of data which is (in some constant way) related to the trigger event you set.
National Instruments

Usb-5132 slow

Hi everybody,
our application requires collecting short signal waveforms (about a few thousand points at 50 MHz sampling rate) with repetition rate at least 20 Hz. We were happy before with Labview 7.1/NI Scope 3.4/ USB-5132/ Low end Dell laptop combination. The experimental setup allowed us easily collect data at about 100 Hz repetition rate.
Our data acquisition program is based on standard example program "niScope EX Configured Acquisition" from "C:\Program Files\National Instruments\LabVIEW X.X\examples\instr\niScope NI provides with every "NIscope" software.
We bought "Labview 2010 Developer Suite", which we installed on newest "Dell Precision M 4500" laptop. But we found USB-5132 now allows us collect data waveforms only at about 10 Hz repetition rate - 10 times slower then with old labview 7.1!
I tested the data acquisition speed with standard "niScope EX Configured Acquisition" program I mentioned above with the trigger set to "immediate" and found the same difference: the sample from NI Labview 7.1 works about 10 times faster compared to new Labview 2010 when the same usb-5132 digitizer is used.
Like I already mentioned, we need at list 20 Hz repetition rate, better more, and we would like to keep easy-to-use USB-5132 digitizer. Can we make it work faster with new Labview?
Thanks,
Yuriy.

Hello Yuriy,
My apologies for not seeing this post a few days ago when you originally posted, but Kyle recently brought it to my attention (I usually monitor the High-Speed Digitizers board but don't always catch posts on the LabVIEW board).
I have done some benchmarking with various versions of the NI-SCOPE driver and a USB digitizer. Unfortunately, it appears that there is an issue in NI-SCOPE 3.6 and later which is causing the fetch (read) rates to be drastically decreased with the USB digitizers. We are implementing a solution to correct this problem and get the fetch rates back to their previous performance values. NI-SCOPE 3.8 will address this problem, though that version will most likely not be ready for release until late Q1 2011. In the mean time, the best option is to downgrade to NI-SCOPE 3.5.2 or earlier if it is possible for the specific LabVIEW version in use. If this downgrade is not possible, please contact National Instruments support by phone or email with your specific details and we will work with you to determine the best solution.
We apologize for any inconvenience this has caused and we appreciate your help in informing us of this issue. Please let me know if there is anything else I can do to help out!
Regards,
Daniel S.
National Instruments

Using USB-9211 to measure a small voltage - apparent signal offset?

Hi,
I wish to acquire a small voltage signal (0-20mV) using USB-9211. I know that this device is designed for use with thermocouples, but I have been informed that it can also be used for measurement of small voltage signals (24 bit resolution over +/- 80mV range).
The problem I am having is that the device seems to generate a small voltage (~3.2mV), which causes a degree of 'offset' in the signal I acquire. My first guess is that this is caused by the internal CJC of the device, however I cannot find any way of removing this signal within LabView. If this is the case, is the magnitude of the offset dependent on the temperature of the device itself?
Can anybody confirm what the source of this voltage is, and advise what is the best way to acquire my signal through LabView?
I have already raised this query with the helpdesk (ref #613180) but have not yet had a definitive answer.
Many thanks
Pete

On Feb 5, 7:10 am, peteryoung <[email protected]> wrote:
> Hi,
>  
> I wish to acquire a small voltage signal (0-20mV) using USB-9211.  I know that this device is designed for use with thermocouples, but I have been informed that it can also be used for measurement of small voltage signals (24 bit resolution over +/- 80mV range).
>  
> The problem I am having is that the device seems to generate a small voltage (~3.2mV), which causes a degree of 'offset' in the signal I acquire.  My first guess is that this is caused by the internal CJC of the device, however I cannot find any way of removing this signal within LabView.  If this is the case, is the magnitude of the offset dependent on the temperature of the device itself?
>  
> Can anybody confirm what the source of this voltage is, and advise what is the best way to acquire my signal through LabView?
>  
> I have already raised this query with the helpdesk (ref #613180) but have not yet had a definitive answer.
>  
> Many thanks
>  
> Pete
The offset is dependent upon the temperature of your cold junction.
To prove this try heating the cold junction with a hair dryer with
your signal leads shorted.
Howard

How correctly using USB 6251 to measure DC voltage

Hi all
I have encounter a problem like in the topic http://forums.ni.com/ni/board/message?board.id=170&message.id=404676&query.id=250408.
I'm sorry for repeating of topic but I've read all of your advices and have not yet resolved problem.
My task very simply: I use USB 6251, differential mode to measure voltage of battery Energizer 1.5V. But result shows >10V ??? Mean.vi shows bigger 4V (see the attached picture)
I don't understand what happed with my task?
Please help me!
Thank so much!
MC
Solved!
Go to Solution.
Attachments:
Acq gragph voltage.JPG ‏22 KB
result of measurement.JPG ‏50 KB

Thank Flaugher
I did not connect bias resistors. But now I do another way: connect possitive pole of battery to the AI0 and other to the AI GRD, choose input configuration "RSE" and get good results.
Attachments:
good results.JPG ‏23 KB

Using USB-8451, and AD7747 from Analog Devices to measure capacitance and convert the capacitance to digital output

Hello,
I am new to LabView and data aqusition. I have LabView 8.5.1 installed on my laptop, and I studied the Getting Started document of LabView, except the data aqusition chapter.
I have microfabricated a differential capacitive sensor, and now I want to test the capabilities of my sensor.
After asking NI engineers, I have been suggested to use USB-8451 with AD7747 (24-Bit Capacitance-to-Digital Converter) from Analog Devices because AD7747 has I2C serial interface.
I have ordered USB-8451, AD7747, and Evaluation Board for AD7747. And I am waiting for them.
Are there any suggestions about how to connect my differential capacitive sensor to AD7747, and eventually to USB-8451?
You may want to know some further information to answer my question:
*The sensor is similar to the sensor on pages 501, 514, and 515 of "Microsystem Design" book from author Stephen D. Senturia.
*The datasheet for AD7747 can be reached from this link: http://www.analog.com/static/imported-files/data_sheets/AD7747.pdf
*My purpose is to make a very precise and accurate "displacement measurement micodevice" by using "the change in the capacitance" during the motion of the mobile fingers of the sensor.
As an initial challenge for myself, I will feel satisfied if I can measure the capacitance change in my sensor when I apply an external mechanical disturbance to my sensor. For example, there must be a change in capacitance if I just swing my hand from top of the sensor region.
I am looking forward for your reply,
Thanks in advance,
Sincerely,
sriverfxtr

Hi Aaron,
Here you go, this is made with a USB-8452.
When you run the code tick the power en dac enable box on.
Maybe you can help me with my problem, I want to use a fiber to sense light from a led.
Do you use any fiber hardware with the TCS3414?
gr,
Attachments:
TCS3414.vi ‏63 KB

How can analog signals are measured every several counters from Quadrature Encoder using USB-6221

how can I sample analog signals every counters from quadrature encoder using usb-6621?

There is a well documented example of what you are trying to do at :
http://zone.ni.com/devzone/explprog.nsf/webmain/DD85F07A7CA99F8F862568690062DE54?opendocument
Don't be afraid because of the BNC-2120. It is just used in this example to simulate the pulses from a device. So it is not needed in your case. Obviously, you will need to change the number of increments/rev according to your encoder to get correct RPM values.

Error 224229 DAQ card NI USB 5132

Dear Sir/ Madam,
Recently two of our DAQ 5132 cards are showing this error, it had been in use for resonance frequency measurements using Laser Doppler Vibrometer through a LabView program interface. Kindly provide suggestions to rectify it.
Regards
Sudhin
Attachments:
DAQ5132 Serial no.ECF4B4 Error.jpg ‏120 KB

Hi All-
Actually, if you are using Windows O/S then you should program your USB-6008 using NI-DAQmx 8.0. Instructions for configuring your device for use with NI-DAQmx are available in this KB. After making this change you may want to convert any NI-DAQmx Base VIs to NI-DAQmx using the NI-DAQmx Base to NI-DAQmx Conversion Utility. You can also use any supported LabVIEW examples from the NI Example Finder (Help>>Find Examples) by browsing to Hardware Input and Output>>DAQmx.
The NI-DAQmx controls for LabVIEW only work with NI-DAQmx; more information is available in this KB. The information is true whether you are using Windows, Linux, or Mac OSX.
Hopefully this helps-
Tom W
National Instruments

USB-5132 ext clock + Trig ?

Hi -
We need ~20 Mhz for 100mS samples, 8 bit , high clock accuracy with big (>3kV) isolation. We have been looking at a USB-5132 , with an optical-fiber to USB converter and supply 5V that floats with the source. We need it to sync with clocks to <10ppm, and while we could run PF1 from our isolated clock system, then we wouldn't have a trigger.We had been hoping to set up the 5132 to acquire whenever it saw a clock pulse, as we can gate or otherwise process our clock signals. I see from other posts though that the 5133 won't do continuous mode so probably not the 5132, eh ? Triggering from the inputs or in software is not an option, unfortunately (would have to trigger 500mS back) Also I had been hoping to find programming or detailed user manuals online but don't see them. Another option I suppose would be a 2 ch ethernet digitizer, but the low cost and ease of use makes the 5132 attractive, as this might be the first of a bunch more. Thanks for any input.
Alex

Hi Jennifer -
The page Matt pointed to, http://zone.ni.com/reference/en-XX/help/370592E-01/TOC6.htm , has the outline of a programming guide. Each link points to a valid page there, but I only found a bit on those pages, e.g.
http://zone.ni.com/reference/en-XX/help/370592E-01/digitizers/step_3-configuring_your_application/
At the bottom of those pages are links to "resources" with potentially interesting and useful stuff, e.g. from that page,
Resources
Array Measurements with the NI-SCOPE Measurements Library for National Instruments High-Speed - NI D...
NI-SCOPE Measurements Library for National Instruments High-Speed Digitizers/Oscilloscopes - - NI De...
Triggering with High-Speed Digitizers - NI Developer Zone
Which yesterday 404'ed but now point back to the Dev Zone main page. If I put say one of those titles into the search bar -
Browse
Search within results:
Triggering with High-Speed Digitizers
...Instruments high-speed digitizers to build...sampling with a high-speed digitizer and various... What is Triggering? A trigger...when the digitizer finds a valid...5124 Video Triggering for more...Fundamentals of High-Speed Digitizers High...Trigger off of with an NI High......
NI High-Speed Digitizers: Optimized for Automated Test
...resolution digitizer, the NI PXI...high-speed digitizers in particular...integration with other types...which NI high speed digitizers...timebase and triggering of several...problems with product quality...alignment with triggering. NI’s...to all NI high-speed digitizers, employs......
and 76 others. thee first two don't work today.
"Triggering With High Speed Digitizers" points to
http://zone.ni.com/devzone/cda/tut/p/id/4363
and "NI High-Speed Digitizers: Optimized for Automated Test " points to
http://zone.ni.com/devzone/cda/tut/p/id/7970
as do a bunch more down the row. Some work though. No the whole, not terribly helpful. Myself, I want linux c/c++ drivers and libraries, but if I have to I'll use (yuck) labview.
HTH
Alex

Why can't I get frequency info from NI USB 5132

Hello
I use NI USB 5132 and try NI Scope example measurement library.
I wonder why I can not get frequency info of input signal.
Thanks
Solved!
Go to Solution.

Thanks for kind responses.
I am using LabVIEW 8.6 on Windows vista and an example called niScope EX Measurement Library.
I am measuring the frequency using a clone called niScope Multi Fetch Measurement Stats.
I am using a pulser producing 60 3V-pulses /sec. When using Soft front panel. sometime I can measure the frequency but sometimes it shows "error."
By the way, I can't see pulse signal from the example but I can see the signal using SCOPE soft front panel.
the error message says
Possible reason(s):
Driver Status: (Hex 0xBFFA2002)
Unable to perform desired measurement operation.
Waveform did not cross the middle reference level at least 3 times. Check the low, mid, and high reference levels. If you are reading a waveform that has a small amplitude, you can use the attribute Hysteresis Percent to reduce the hysteresis thresholds.
Please let me know if more info is needed
Thanks
Cynitha

Using USB NI-6008 on LV7.1 the results data has to be in Excel. It looks as cluster data format that i can not insert into excel VI

I am Using USB 6008 with LV 7.1. The application is voltage logger and i would like to use excel and upload the data . The Columns will be the channels and the rows will be the data.
The data comes from the DAQmx vi not like a simple string or an number it is kind of cluster data
which contains strings and numbers and more for each measurement.
I tryed to work with spraedshit and it goes ok but it is not conveniant to convert later to excel.
Do you have a solution for that please?
(How to extract the data from the cluster type format that is used with USB6008).
TX arik
Attachments:
USB-6008-r3.vi ‏80 KB

Arik:
I hope all is well. If you are trying to write data to a text file along with the header information, you could do the following:
1. Open a reference to a file and write the header information right away.
2. Do your continuous acquisition (in a loop) using the 6008 and write the data to a file everytime.
3. With the proper formatting, your colums will represent channels and your rows data.
Please take a look at the attached example and let me know if you have any other questions.
Regards,
Rudi N.
Attachments:
WriteFilewHeaders.vi ‏64 KB

DAQ vi to perform digital write and read measurements using 32 bits binary data saved in a file

Hi
DAQ vi to perform digital write and read measurements using 32 bits binary data saved in a file
Two main
sections:
1)
Perform
write and read operations to and fro different spread sheet files, such that
each file have a single row of 32bits different binary data (analogous to 1D
array) where the left most bit is the MSB. I don’t want to manually enter the
32 bits binary data, I want the data written or read just by opening a file
name saves with the intended data.
      2)
And
by using test patterns implemented using the digital pattern generator or build digital data functions or otherwise, I need to
ensure that the
            binary data written to a spreadsheet file or any supported file type
then through the NI-USB 6509 is same as the data read.
I’m aware I can’t use the simulated
device to read data written to any port but if the write part of the vi works I
‘m sure the read part will work on the physical device which I’ll buy later.
My Plan
of action
I’ve
created a basic write/read file task and a write/read DAQ task for NI USB 6509
and both combine in a while loop to form a progress VI which I’m confuse of how
to proceed with the implementation.
My
greatest problem is to link both together with the correct functions or operators
such that there are no syntax/execution errors and thus achieve my intended
result.
This
project is one of my many assignments for my master thesis, so please i’ll
appreciate every help as I’m not really efficient with LabVIEW programming but
I prefer it because is fun and interesting if I get to know it.
Currently I’m
practicing with LabVIEW 8.6/NI DAQmx 8.8 Demo versions and NI USB 6509
simulated device.
Please see
the attached file for my novice progress, thanks in
advance for the support
Rgds
Paul
Attachments:
DIO_write_read DAQ from file.vi ‏17 KB

What does your file look like? The DAQmx write is expecting a single U32 value, not an array of I64.
Message Edited by vt92 on 09-16-2009 02:42 PM
"There is a God shaped vacuum in the heart of every man which cannot be filled by any created thing, but only by God, the Creator, made known through Jesus." - Blaise Pascal

External reference for USB 5132

Hello,
I have a couple (hopefully) general questions about using an external reference clock on our USB 5132 digitizer. We want to lock it to the other oscillators in our system, all of which are presently locked to one 10 MHz reference. If I connect our existing 10 MHz reference to the PFI1 input, my questions are:
1. Is the 5132 now locked to our system? Or, do we need to specifiy in the setup software that we want to override the 5132's internal reference and rely entirely our external reference?
2. In order to have the best possible lock, do we need to tell the 5132 to sample at a frequency that is evenly divisible by 10 MHz (e.g. 20 MHz, 10 MHz, 5 MHz, 2 MHz, etc.)? Similarly, are we worse off if we want to sample at say, 13 MHz?
Thanks for any thoughts.
Best regards,
Penny
Solved!
Go to Solution.

Hello Penny,
1. Yes the 5132 is locked to your reference system 10MHz clock (with some offset due to delay in the time it takes to transmit the clock signal from your system to this USB device) if you selected the PFI line as the source of an external timebase. Please take a look at the following example Help>>Find Examples>>Hardware Input and Output>> Modular Instruments>>NI-Scope>>Features>> niScope EX External Clocking.vi.
2. No, although I would expect that if you enter in 13MHz and your device was not capable of doing this it would coerce it to the closest value. I would suspect that only integer divide downs from the clock in question are valid such that 12. 5MHz is the value it would coerce to if you were to request a 13MHz value (with a 50MHzexternal clock). The 5132 can not do RIS so sampling at 20MHz with a 10MHz SampleClock Timebase Source is not feasable.
Regards,
Izzy O.
Applications Engineer
National Instruments
www.ni.com/support

Is my external drive using USB 2.0?

I just hooked up an external USB 2.0 drive. I'm copying my iPhoto library (22 GB) to it. I estimated that using USB 2.0 this should take about 6.5 minutes. Well it has been going for well over an hour and isn't half way done. I used to use this drive on my Windows machine and it is formated as MS-DOS FAT32. Is that what is slowing me down? How can I check that Leopard is using the device as 2.0 and not 1.1?
TIA!

I was using this site:
http://www.convert-me.com/en/convert/units/datatransfer_rate/data_transferrate.dUSBtwo.en.html
I guess that is for a single file and not a bunch of small files. I still figured it would be much faster than the 3-4 hours it is going to take.
That chart is based on theoretical rates. USB really never gets near those speeds.
<http://www.barefeats.com/usb2.html>
<http://lyberty.com/tech/terms/usb.html>
"Therefore, actual data transfer rate [of USB 2.0 High-speed] will be lower than 480 mbps (57.2 MB/s).
Our measurement result of data transfer rate with USB 2.0 storage device (HDD) is about 20 - 25 MB/s on average."

Ripple Measurement using USB 5132

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