USB-6211 special DO pulstrain

Hello,
I have a USB-6211 and I want to generate a pulstrain for a power supply.
The pulstrain is determined in ms on and off time (e.g. 49ms off, 1ms on, 5V).
The length of the pulstrain is infinite, but must be haltet when an error happens.
(I do not understand why I need to configure the length of the train in before hand, I just want on or off.)
What is the best method to do this?
Kudos will be given!
Thank you
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Can anyone give me a hint please.
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Similar Messages

Signal generator fo usb-6211

Hallo, I'm in the process of generating square wave with adjustable duty cycle for my usb-6211. After searching, I find two generators available: IVI FGEN, and DAQ Assistant. The latter seems suitable to my device, but without capability of changing duty cycle. Consequently, I'd love to know whether there exists any kind of signal generator which yields up square wave with adjustable duty cycle and whether it is feasible to connect it to DAQmx Write to feed to the signal to AO0/1 of my usb-6211.
thanks in advance,
win2

Hi win2,
you are right, the DAQmx functions are what you need. The FGEN drivers are only for the hardware based function generators.
As you mentioned that you use DAQ Assistant, I guess you use LAbVIEW (which version?) to try to produce the rectangel with adjustable duty size.
Right? Please let me know, which version of DAQmx you have installed on your PC, too.
Here you have two links, where you can find an example how to generate a squares with adjustable duty cycle using the analog output.
This example, i guess, is what you want to achieve:
http://zone.ni.com/devzone/cda/epd/p/id/5235
It shows, how to use software timing to adjust the duty cycle.
The second example shows, how to create a "selfmade" signal:
http://zone.ni.com/devzone/cda/epd/p/id/1621
If you want to send TTL signals, please keep in mind that you can use one of the four digital outputs.
Creating a digital pulstrain allows to set the duty cycle directly.
I hope, this helps
regards
Kilian

How to send TTL output AND acquire AI voltage data using USB-6211

Hello,
I am relatively new to Labview, so please bear with me. I have a research application involving 2 pressure transducers and a high-speed camera. I wish to acquire analog voltage data from the 2 pressure transducers. However, at the start of the acquisition, I will need to send a single TTL output to trigger the camera. This TTL pulse must be sent out at exactly the same time that the AI acquisition begins, in order to ensure that my 2 pressure measurements and camera images are 'synchronized' in time.
Is this possible on the USB-6211 running with LabView 8.20? I currently have a fairly simple LabVIEW vi that uses a software trigger to start an AI acquisition - I have attached it with hopes that it may help anyone willing to assist me. I would prefer to be able to simply add something to it so that it will output a TTL pulse at the start of the acquisition.
Thank you in advance.
Regards, Larry
Message Edited by Larry_6211 on 12-19-2008 11:24 AM
Attachments:
USB6211_v1.vi ‏212 KB

Hi All,
I'd like to clear a few things up. First, you'll find that if you try to set the delay from ai start trigger and delay from ai sample clock to 0, you'll get an error. Due to hardware synchronization and delays, the min you can set is two. Note that when I say two, I am referring to two tick of the AI Sample clock timebase, which for most acquisitions is the 20MHz timebase. I modified a shipping example so you can play around with those delays if you want to - I find that exporting the signals and looking at them with a scope helps me visualize what is going on. The Manual has some good timing diagrams as well but it looks like you've already hit that. The defaults would give you a delay of 250ns from the start trigger - is this too high for your situation? What is an acceptable delay? I tend to think that "exactly the same time" is a measure of how precise rather than an absolute (think delays in cable length making a difference.)
With all that in mind, I see a few options:
Start your camera off of the AI start trigger (an internal signal) and just know it is 250 ns before your first convert.
Export the convert clock to use as a trigger. This assumes your camera can ignore the next set of convert clocks.
More complicated option: Internally you have an ai start trigger, sample clock and convert clock. From your start trigger to the first convert is 250ns but if you export your convert clock you're going to get future convert clocks as well. One option would be to generate a single triggered pulse using a counter (start with the Gen Dig Pulse-Dig Start.vi example) with the AI start trigger as the trigger for the counter, an initial delay of 250 ns, and a high time of whatever you want it to be. This should give you a singe pulse at very close to same time (on the order of path delays) as your first convert clock.
Hope this helps,
Andrew S
MIO DAQ Product Support Engineer
Getting Started with NI-DAQmx
Measurement Fundamentals
Attachments:
Acq&Graph Voltage-Int Clk.vi ‏37 KB

How to output the digital clock and synchronization signal from the NI USB-6211

Hello,
I need to connect the NI USB-6211 to control a digital to analog convertor chip (AD5541). However, this chip requires three input signals :1) Clock input, 2) Logic input or a synchronization signal and 3) Signal Serial Data input (CS, SCLK, DIN).
how to output the digital clock and the synchronization signal from the NI USB-6211?

Hi SaberSaber,
You should be able to use the counters to generate a pulse train that could be used for clock and synch purposes.
Hope this helps. Let us know if you have more questions.
Dave C.
Applications Engineer
National Instruments

Can you record sound using a USB 6211 and convert the data to a .wav (or other sound) file?

Hello,
I am trying to build a system that will use a USB 6211 to record sounds from multiple electret microphones and then save the data as a .wav file or other sound file. I have already built my mics and hooked the mics up to the USB 6211; the DAQ device seems to do an adequate job recording the signal - I've recorded from 3 mics at a time at 11,025 Hz, although I don't know how good the signals are since I can't save them for playback after the fact, and they aren't going through my sound card. Ultimately, I would like to save the data as a multichannel audio file which I could then open in a program such as Audacity for further editing and analysis. Since Audacity can import a variety of sound files, my file format doesn't need to be .wav if another format would work better.
Any advice would be appreciated.
Thanks, Eric

If you are sampling all three simultaneously, your highest frequency recordable will be (11,025/2)/3, so about 1800Hz and that will pretty coarse (traditionally digital sound recording is at 44Ks/s at the low end). As to converting to a .wav, there are functions on the "Graphics and Sound" palette for saving waveforms to a .wav file.
Putnam
Certified LabVIEW Developer
Senior Test Engineer
Currently using LV 6.1-LabVIEW 2012, RT8.5
LabVIEW Champion

How to use voltage signals as input signals into USB-6211

Hello everyone,
I have a USB-6211 and a PDQ80A -quadrant photo detectot from thorlabs, i am trying to take three voltage signals from the PDQ80A into my PC using USB-6211 from NI. THese voltage signals are X,Y and sum (X+Y).
Looking forward to your reply.
Thanks in advance,
_Perseus

Technically, the question was in the title. But of course, the answer to that is... Connect them using WIRES. It's designed for voltage signals, just wire your cell outputs to whatever DAQ input channels you're going to read.
Using LabVIEW: 7.1.1, 8.5.1 & 2013

Trigger rearm time on USB 6211

I am using a USB 6211 to generate raster waveform and digital trigger to drive the galvanormeter mirror. I just want to send one cycle of waveform for every trigger pulse. The problem is that it seems like the USB 6211 trigger rearm speed is limited to about 20 Hz, which is quite low. Is this correct?
Any solution?
Attachments:
Triggering.png ‏76 KB

I might use the wrong word to explain it. What I mean by observing the behavior of the device when it was programmed as shown in the code is that no matter how fast my triggering clock was, there seem to be a certain period of time when the device did not accept any trigger pluse. That period of time was about 50 ms or about 20 Hz clock rate. The code worked as I expected it to be at trigger frequency less than 20 Hz. As soon as the clock speed pass 20 Hz, the extra pulse was not accepted.
One thing that I did to verify the 50 ms time limit was by sending 200 Hz of clockspeed and found that the one that close to 50 ms did trig the device.
Is there any example how to setup this device to surpass that trigger speed?
If not possible with the USB 6211, which DAQ device you would reccomend to achieve more than 100 Hz trigger speed, or even better for up to 200 Hz?
Thanks for your response : )

How to measure frequency by USB 6211?

Dear all,
I'm using USB 6211 to measure the input analog voltage signal, then use a counter to yield the frequency. Please find the VI figure in the attachement.
The problem is the insteal of measure the right frequency, which is from 300Hz to 1000Hz. There is a lot of high frequency noise from thousand to milliion Hz. I think it pick up the high frequency harmonics. How to avoid it or use a more effective way to achieve the measurements.
Regards,
Alan
Attachments:
flow rate frequency measurement.JPG ‏43 KB

You have to suppress high frequencies on the analog side of your signal. You must set it to a frequency which is not higher than half of your aquisition rate. If you sample with 10 kHz your filter must have a cutoff frequency of max. 5 kHz. Otherwise you will see the signal mirrored at the half of the sample rate. A 6kHz signal will lead to a 4 kHz signal after the sampling.
Waldemar
Using 7.1.1, 8.5.1, 8.6.1, 2009 on XP and RT
Don't forget to give Kudos to good answers and/or questions

USB-6211 - Getting Error 50103 when attempting to use two counter method

I am using a USB-6211 and want to measure the speed of a motor by counting pulses coming back from sensors on the motor. Speed will vary from 0 to about 5k Hz.
My strategy is to use "Method 2" in the manual to measure using two counters. To do this I am attempting to generate pulses of known duration with Counter 0, route these pulses to the gate of Counter 1, send the motor pulses into the source of the counter1 and letting the counter determine and report the number of pulses that occur during the "gate time".
To get the pulse generator going at 8,333 Hz I do this:
AGniDAQmx_CreateTask(instrHandle,"TimingPulses, Task_Handle8)
AGniDAQmx_CreateCOPulseChanFreq(instrHandle, Task_Handle8,"Dev1/Ctr0","Out",DAQmx_Val_Hz,0,8.333,0.5)
AGniDAQmx_CfgImplicitTiming(instHandle, Task_Handle8, DAQmx_ValContStamps,1000)
AGniDAQmx_StartTask(instrHandle, Task_Handle8)
This works fine. (By the way, I do stop and clear the task before exiting.)
Now I add this code in a new task to try to use the Counter0 pulses to measure the input pulses with Counter1.
AGniDAQmx_CreateTask(instrHandle,"MotorPulses, Task_Handle5)
AGniDAQmx_CreateCIFreqChan(instrHandle,Task_Handle5,"Dev/ctr1",MotorPulses,0,10k,DAQmx_Val_Hz,DAQmx_Val_Rising,DAQmx_ValHighFreq2Ctr,0.12,10,"")
AGniDAQmx_ReadCounterScalarU32(instrHandle,Task_Handle5,10,E)
AGniDAQmx_ClearTask(instrHandle,Task_Handle5)
This function fails on the CreateCIFreqChan() call with an DAQMXError 50103.
Apparently Counter1 resources are being tied up by Counter0. Is this true?
Any suggestions?
Thanks,
-CBJohnson

Hi Mallori,
Thanks for the great reply message. I do appreciate your help.
Yes, I think you understand my application. The motor can turn from zero to about 5K RPM and one pulse is generated with each turn of the motor.
This application is using Agilent VEE but the statements are "C-like" so that's why I posted them like that. I can't "cut-and-paste" directly from the VEE statements and I have to type them.  I mis-typed the Implicit Timing statement. It was missing an "_". It should have been:
AGniDAQmx_CfgImplicitTiming(instrHandle,Task_Handle8,DAQmx_Val_ContStamps,1000)
I think I understand what you are saying about DAQmx_Val_HighFreq2Ctr using the resources from both counters That explains why I get the message about resources not being available.
I have tried to use Counter Method 1 and it *almost* worked.  A problem comes about when the motor speed is zero (stopped) and, since these motor pulses are being fed into the Gate of the counter, the zero value makes it simply time out. Increasing the timeout value to infinite (-1) makes the entire program hang. I need it to go on -- looking for other user input, reporting other data being collected, etc. If the counter is waiting for the Gate signal to rise to start counting and to drop to stop counting and do the calculation, it will not work since it just times out.  I went to this counter method (actually called counter method 3 in the DAQ manual) because then I am trying to generate the pulses of known period and send these pulses to the Gate.  Then I am feeding my pulses into the Source of the counter and letting it determine how many pulses occured during the "gate time". In this case, zero pulses during the "gate time" should be OK; it should simply report that zero pulses were detected and start counting again on the next rise of the Gate pulse.  I thought I could simpy adjust the length the "gate time" to measure my range of frequencies.
Make sense? Any way to do this with the two counters of the USB-6211?
Thanks, Mallori,
-Craig

How to make ROD426 connected to USB-6211 work in Labview

Hello
I have a rotary encoder type Hadenhein ROD426 connected to a USB-6211 I/O modul.
I need to make this work in Labview, so i can read the position for the rotary encoder by angle. I can't find anny tools in Labview that does this.
Does annyone have anny tips?
Gøran Steen

Gsteen,
There are some examples in LabVIEW's Example Finder (Help menu -> Find Examples...) that might help. Try Hardware Input and Output -> DAQmx -> Counter Measurements -> Position. These examples are usually a great place to start. I looked at "Meas Angular Position-Buffered-Finite-Ext Clk.vi" which looks like it may be of help to you. You can also limit the example finder to only find examples that pertain to your hardware (USB-6211) by configuring the "Hardware" dropdown in the lower left-hand corner of the example finder. If you are browsing, check the "Requirements" list in the lower right-hand to see if a particular example works with your DAQ.
-cb

USB 6211 Counter

Hi. Does anyone know how I can drive a 0-12V PWM device with the 6211? How can I control the frequency of the pulse?
Thanks!

Hi Seascan,
What type of application are you working with in regards to PWM and this device? The 6211 does not support hardware timing, therefore the duty cycle/frequency will update as fast as the processor can handle or execute. There was a similar question on using PWM with the USB-6211 on a previous forum. Have a look at it here and if you have any further questions please let me know.
http://forums.ni.com/t5/Counter-Timer/NI-DAQmx-M-Series-Pulse-Width-Modulation-PWM-not-working-with/...
Regards,
Ben N.
Applications Engineering
ni.com/support

Compatibilité CompactRIO et NI uSB 6211

Bonjour à tous,
voila je cherche à réaliser depuis peu le développement d'un pot vibrant. En naviguant sur le net et en cherchant quelques exemples je suis tombé sur un programme qui réalise exactement mes souhaits. Mais avec "compactRIO" avec un matériel donc différent du mien. Je voulais savoir s'il était aisé de pouvoir modifier ce programme afin de réaliser la commande de mon pot vibrant à l'aide de ce programme.
Je dispose d'un boitier NI usb 6211 et d'un accélèromètre dont voici les documentations...
Cordialement
Pièces jointes :
Shaker Control Source.zip ‏3005 KB
ICP 120.pdf ‏145 KB

Bonjour,
Les parties sur lesquelles vous vous posez des questions sont de la programmation FPGA et ce n'est pas possible avec votre carte USB.
Ainsi si vous tenez à garder cet exemple de code.
Il vous faudra coder avec des foctions DAQmx (driver de votre carte DAQ). Pour ce faire, je vous invite à regarder les exemples fournis avec votre logiciel LabVIEW.
Vous lancez LabVIEW => Aide => Recherche d'exmples => Matériel E/S => DAQmx
Je vous invite à tester différents VIs avec votre matériel.
De plus, je suis persuadé que vous pouvez trouver des exemples sur notre site internet : www.ni.com dans l'onglet recherche, vous tapez Daqmx et analog par exemple et vous aurez pas mal d'information. Il faudra peut être faire attention à ce que vous retourne votre accéléromètre (mV, V?) et ainsi réaliser une échelle adaptée.
Enfin, vous pouvez aussi bien utiliser le VI express DAQ assistant.
http://www.ni.com/white-paper/5467/en/
Cordialement,
Matthieu RICORD
National Instruments France
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Usb-6211 utilisable avec quelle version de Labview

Bonjour,
J'envisage d'acheter une carte USB-6211, mais je lis que l'on ne peut l'utiliser qu'à partir de LV 7.1.
Or ma version favorite est LV 7.0, pourquoi ne pourrait-on pas l'utiliser avec LV 7.0 ?
Résolu !
Accéder à la solution.

Bonjour,
Parceque la version de LabVIEW est liée à la version des drivers (DAQmx) pour piloter votre matériel.
La dernière version compatible de DAQmx avec LabVIEW 7.0 est la version 8.1 comme montré sur cette page :
Compatibilité entre les versions de LabVIEW et du driver NI-DAQ (Windows)
Et dans la version 8.1 de DAQmx, le périphérique USB-6211 n'est pas encore supporté (et ne devait pas exister à la sortie de ce driver).
Cordialement,
Da Helmut

Externally controlled counter direction with USB-6211

I am using a USB-6211 and created a simple read counter application with the DAQ Assistant. It counts pulses (1 sample on demand) on Counter 0 (PFI0). When I set Direction to Externally Contolled it does not work properly. It counts random up and down. According to the manual my direction input line is Ctr 0 B (PFI1), but the level of this pin has no effect. What am I doing wrong?

Hello Steffan,
According to the following Knowledge Base you have cannot use the default settings wehn trying to externaly control the direction of the counter:
http://digital.ni.com/public.nsf/allkb/1A8818274130FA388625722E00760CC9?OpenDocument
Since these changes cannot be done in the DAQ assistant you have to use the DAQmx API to resolve this. I have attached a small example that does a simple event count on the source pin of counter 0 (which is also the A input of the counter). With a property node I have set the Counter Direction input terminal to PFI 1 (which is the B input). Now when the PFI 1 is low you will count up, when it is high you will count down.
hope this helps,
Regards,
RikP - National Instruments Applications Engineering
Message Edited by RikP on 06-05-2008 10:12 AM
Rik Prins, CLD
Applications Engineering Specialist Northern Europe, National Instruments
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Attachments:
Count Digital Events Up-Down USB-621x.vi ‏33 KB

Usb 6211 and LabView - good for IV characteristic aquisition?

Hi there,
I pre-emptively declare my lowest level in using LabView and all the annex tools, so my question won't result too silly.
I need to automatically acquire the IV characteristics for 4 solar devices, so I am thinking about connecting them to the USB 6211 in order to switch from one device to another one.
My question is: can I use a LabView Program in order to simulate the Voltage signal to apply (range c.ca -1 to +1 V), and then collect the relative current?
If so, how??
Many thanks in advance for any sort of help.
Laura

http://zone.ni.com/devzone/cda/epd/p/id/5918
http://zone.ni.com/devzone/cda/tut/p/id/7229
LabVIEW has a toolkit available for this. It uses an SMU card but you could simulate that with your 6211 and a current sensing resistor.
Using LabVIEW: 7.1.1, 8.5.1 & 2013

USB-6211 special DO pulstrain

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