NI 9234

Bonjour à tous,
Sur le module 9234 comment définir la résolution de mesure ?
c'est à dire : lorsque j'appel la fonction 'DAQmxCreateAIVoltageChan' elle prend en paramètre, des valeurs de tension min et max.
A quoi corresponde ces valeurs ?
Es ce que par exemple lorsque je met [-1v,1v] comme valeurs, es ce que la résolution est plus importante que si je mets [-5v,5v] ?
Autre question :
Lorsque j'appel la fonction : 'DAQmxCfgSampClkTiming' je configure l'échantillonage à 51200E/s/voie et 10240 échantillons à lire.
Es ce que cela signifie que si je configure 3 voies dans une tâche, chaque voie est échantilloné à 51200 et récupère 10240 Echantillons ?
Merci pour vos réponse,
Cordialement,
Stéphane

Bonjour,
Merci d'avoir posté votre question sur les forum de National Instruments.
Les valeurs indiquées comme tension min et max lors de la création de votre tâche vont être utilisées par le driver DAQmx pour sélectionner, au sein de votre module, la gamme de mesure la plus appropriée pour le signal que vous attendez. Vous aurez ainsi un convertisseur analogique/numérique paramétré au plus juste pour votre signal et vous bénéficierez ainsi de la meilleure résolution possible pour votre acquisition.
Ce qu'il faut retenir c'est que votre C A/N utilisé dans le module à une résolution fixe. Du coup, plus vous indiquez une gamme de tension proche de votre signal réel, plus la résolution utile pour votre acquisition est importante. Imaginons que votre convertisseur possède 3 bits de résolution, soit 2^3 = 8 niveaux différents de conversion. Si votre signal est une sinusoide d'amplitude (-1V, 1V) et que vous avze paramétré votre gamme de mesure sur (-1V, 1V) par le biais des valeurs V min et Vmax, vous bénéficiez de ces 8 niveaux pour la totalité de votre signal. Si vous avez par contre paramétré votre acquisition pour une mesure de -10V à 10V, les 8 niveaux seront répartis sur toute cette plage et donc vous n'utiliserez pas tous les niveaux de conversion pour votre signal (sans doute seulement 1 ou 2).
En ce qui concerne votre seconde question, la réponse est oui, la configuration est pour une voie. L'hrologe d'échantillonage et le nombre de point à récupérer seront les mêmes pour vos trois voies et seront égaux aux valeurs que vous avez indiquées.
J'espère que ces informations pourront vous aider.
Bien cordialement,
Guillaume H.
National Instruments France
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CRIO and ni 9234 modules not working or communicating through fpga with accelerometers, fpga connected to real time application which is also connected to shared variables linked to modbus slave

Hi,
I have a compact rio which has a 4 way chassis attached to that chassis is three ni9234 modules they are linked using fpga to a real time application then using shared variables in the low speed loop that are linked to a modbus slave to communicate with dcs, the ni 9234's have accelerometers connected to them with iepe ac coupled option on the c modules, my problem is the real time application seems to be running okay even when power loss occurs it restarts with no problem and the fpga writes to the portable hard drive bin files fine but without a accelerometer connected I get low noise readings as soon as I connect a accelerometer to any one of the 10 outputs it just goes to a fixed number (0.03125) as soon as disconnect it again it reverts back to reading noise, I have run a scan on the modules and only get a spike when I connect or disconnect the accelerometer, I have tested the voltage at the pins of the module and I get 22 volts dc which makes it more likely that the hardware is not the problem but a software is maybe causing this to hang-up, I attach project and files for your perusal. I also carried out a new project which in scan mode directly linked the module input to shared variable and the same scenerio again. Help would be much appretiated.
Many thanks
Jason
Solved!
Go to Solution.
Attachments:
logger 2plusmodbus2.zip ‏679 KB

Whren using waveform acquisition with the 9234s we recommend the following FPGA and RT template.
http://sine.ni.com/nips/cds/view/p/lang/en/nid/209114
it can be extended as a data logger with:
http://zone.ni.com/devzone/cda/epd/p/id/6388
or using shared variables combined with scan engine
http://zone.ni.com/devzone/cda/tut/p/id/9851
The FPGA in all of these, as well as the RT framework have been used successfully by 1000s of users. I would recommend giving these a try.
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

Any way to synchronize two NI-9234 devices?

I'm pretty sure it cannot be done without having a common analog input and determining the delay by cross correlation but I wouldn't mind to be proven wrong.
1. There are no external clock inputs for the device.
2. Also the timing loop is weird. In my case for a nominal 100ms acquisition time the loops times jump between 60 and 120 ms with an average over 100 samples of .097.
The NI-9123 is a nice device to remotely locate but it seems to lack the ability to synchronize with other DAQs.
Mark

Hi Mark,
Thank you for using the forums. To answer your question, NI-9234 devices can be synchronized using a cDAQ chassis. The timebase, sync pulse and start trigger are shared through the back plane of the chassis. These can be shared automatically by using channel expansion in your DAQmx task. That is to say that you choose multiple channels on multiple cards and have them all be in the same task. Here is a great article that explains how to synchronize multiple DSA cards within the same chassis.
For question 2 could you elaborate a little more about your timing loop, are you actually using a timed loop, or a while loop with a timing mechanism to control it? I am assuming that you are using a Windows based OS, if that is the case it is generally not a good idea to use timed loops because Windows is a non-deministic OS and could actually decrease performance. Please let me know what you are using and if you could post some sample code that is exhibiting this behaviour that would be great.
Regards,
Brian P.
Applications Engineer
National Instruments

Can I use the NI DAQmxbase C functions to develop a Smart Device application using a NI USB or NI ENET 9234 C module with Visual Studio for an iMX31 (ARM 11) embedded computer running Win CE 5.0 or 6.0?

I have an embedded application running on a iMX31 (ARM 11) that does fairly high performance analog input (24 bit, 50K samples/second). I use Microsoft Visual Studio 2005 C/C++ for the develoment environment and have currently built versions of the application for Win CE 5.0 and 6.0 without Labview or NI hardware. I have used the NI 9234 with great success on several Labview applications in the past and I'd like to use the 9234 on this embedded application with VS2005 C/C++. The NI documentation hints that I should be able to do this (maybe I'm overly optimistic) and I'm wondering if anyone else has? I've tried the Evaluation versions of Labview Mobile and Labview Touch panel to build a C application using the NI DAQmx base C function inside Visual Studio without success. I can compile and link the ContAcq IntClk LV example project for an x86 platform using NIDAQmx but not for a ARM platform using NIDAQmxbase.lib. I get the same linker error error LNK2019: unresolved external symbol referred to in Knowledge Base Document ID 4HAEE7QQ even though I've set up (or think I've set up ) VS2005 as the KB article indicates.
If anyone has used the C functions and NIDAQmxbase library inside a VS2005 Smart Device project, I'd greatly appreciate your comments.
Thanks

Hello Gene,
I have been checking into this for you and have found out that what you are trying to do cannot be done. At least not in the current manner you are hoping for. The internal architecture of DAQmx Base requires the cross-compiling capability of the LabVIEW Mobile Module. While a stand-alone compiler can compile DAQmx Base calls for desktop processors, it cannot compile DAQmx Base calls for ARM.
If your application requirements exclude the LabVIEW toolchain, then the remaining option is the USB Driver Development Kit which is avaliable here, but you will have to contact your local field sales representative to discuss support
options as standard phone and e-mail support are not available for the
NI Measurement Hardware DDK.
NI Measurement Hardware Driver Development Kit
http://digital.ni.com/express.nsf/bycode/exyv4w?opendocument&lang=en&node=seminar_US
ColeR
Field Engineer

Windows 7 NI-9234 Time Out

I'm getting a 50405 message on the NI-9234 on a Windows 7 machine.
"Error -50405 occurred at Read DAQ 1 and Process Data.vi
Possible reason(s):
NI Platform Services: No transfer is in progress because the transfer was aborted by the client. The operation could not be completed as specified."
It runs for 10 - 60+ minutes then it fails.
I'm checking AvailSamplesperChannel and they seem very low with the Maximum value seen as 2000.
Your thoughts.
Thanks,
Mark
Solved!
Go to Solution.

OK I'll shake the magic 8-ball (Sometimes it works)
Q: ~~~~~Is the CompactDAQ chassis connected by USB through a hub being shut down by Windows Power manager?~~~~~~
A: It seams likely without knowing more.
Jeff

What type of IEPE accelerometers can I connect to NI 9234?

Hello.
I have a compactDAQ with NI 9234 to connect accelerometers. I want to perform some vibration measurements using it together the accelerometer in attachment (101.51-6D-2-M6).
Will the acceleromter work properly with NI 9234? Do I have restrictions about IEPE acceleromters for NI 9234?
Thanks,
Daniel
Attachments:
ICP Accelerometer.pdf ‏797 KB

Yea, you are rigth about the current, didn't take the time to look closer at the sensor spec.
The 9234 will provide 19V @ 2mA but that is no problem, since the AC input range is (only) +-5V , so there is enough headroom unless your sensor will provide more than about 5V amplitude.
See Page 22 of the user manual
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
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Is there any plan to for usb 9234 to support hardware trigger?

We expect to provide our low cost modal testing solution based on NI usb-9234 and ModalVIEW software. Hardware trigger is needed when using usb 9234 to perform impact testing.
Message Edited by Troglodyte on 07-11-2008 10:44 PM

Thank you for your post.
In order to keep the power of the board to a minimum, and to keep our prices very competitive, our customers use software triggering for applications such as impact hammer test. We are happy to coach your development team in the implementation of software analog triggering in LabVIEW, Our Sound and Vibration Assistant, or with our "C" Api. I have asked our Product Support Engineer to post a note regarding the "C" api function calls. Stay tuned.
Also, please feel free to contact us directly as the need arises.
Sincerely,
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

Problem triggering NI-9234 from 9401

I am trying to trigger a 9234 from a 9401 connected to a PLC. There are 4 input triggers connected to the first 4 channels of the 9401, corresponding to 4 phases of a test. For each phase of the test, I am looking for a trigger on a different channel. The problem is that the acquisition is triggered from any of the 4 input channels, i.e. when I specify a trigger on the first channel, PFI0, a trigger from PFI1, PFI2 or PFI3 also causes the acquisition to launch.
In using the NI example, “Acq&Graph Voltage-Int Clk-Dig Start.vi”, I am able to reproduce this behavior. I configure the trigger source to be PFI0, Rising Edge, on the 9401. The acquisition is triggered even if the rising edge is passed on channel 1, 2 or 3. Trigger signal level is 0-5V.
LV2011, DaqMX V9.4, Windows XP
Attachments:
Acq&Graph Voltage-Int Clk-Dig Start.vi ‏28 KB

I have figured out the problem and the solution. To simulate the triggers sent by the PLC, a box was made containing 4 switches supplied by a common 5V source. Apparently, electronic noise is generated when a switch is activated and fed back though the other switches. This was causing erroneous triggers to be detected. So, I added a trigger property node, enabled the digital filter on the trigger signal with a minimum pulse width of 0.1 milliseconds (0.0001 sec). This cured the problem of triggering from any channel.
The filtering will also be useful to help eliminate false triggers caused by electronic noise in the production environment, which has also been a problem.
Thanks for all those who viewed and I hope this can be helpful to someone in the future.
Joe
Attachments:
Acq&Graph Voltage-Int Clk-Dig Start Dig Filter.vi ‏30 KB

NI 9234 : sampling rate : cRIO, FPGA

For NI 9234 module, front panel and block diagram of my FPGA code of my cRIO is like below.
The sampling rate (data rate) is selectable between some values as shown below.
Do you have any idea how I can do the sampling with a lower rate that is smaller than the samllest option (1.652 KS/s)?
Solved!
Go to Solution.

Hi Cashany,
Take a look at this link. Page 16 describes the limitation that you are running into. Basically the master time base can only be divided down to certain data rates because of the way the device physically handles digital and analog filitering. So there really isn't a way to divide down past that point.
Ryan
Applications Engineer
National Instruments

NI 9234 with NI myRIO

Hi Everyone,
Is it possible to use NI 9234 and NI USB-9162 with NI myRIO? or is it there any similar module for NI myRIO?
Thank you!
ABSIAS

Hi Jovan N.,
Thank you for replying. Today I installed NI DAQ, and was able to use NI USB 9162 with PC, but still couldn't with myRIO. Tomorrow I try to do what you suggested.
Here I attached the example from NI for Active Noise Cancellation for cRIO, I changed it a little bit for myRIO. Can you tell me please how to change the host.vi, because for my project I don't need any s(n), I need to get e(n)=0, what I mean I am not trying to filter signal from noise, I have only noise, and I want to cancel it. I attach my block diagram here.
Thank you very much.
ABSIAS
Attachments:
FXLMS.zip ‏598 KB
FXLMS_NEW.zip ‏230 KB
13.PNG ‏69 KB

I want to measure PCB 203B force transducer with NI 9234 module in a DC coupled manner - How

The transducer is an IEPE stype and when I turn on IEPE excitation, I can't do a DC coupling. Am I left to using some type of external amp?

From memory, PCB ICP load cells (that's IEPE by another name) have a typical bias voltage of around 10 V, which is usually stripped by a capacitor on the excitation amplifier (or the 9234 in this case). I used to have a series of triaxial load cells that were biased to 10.25 V.
PCB sell a number of relatively inexpensive external amplifiers themselves, but take care to mention to their sales representative that your interest lies in static or quasi-static measurements. I bought a 482C05 four channel amp and decided to use it for low-rate tests, and found that the decay was considerable in one set of tests thanks to the amplifier time constant. One cheap and cheerful solution was to connect a BNC T-piece at the amplifier/load cell connector and branch off the signal. This is where the bias voltage is important - I was fortunate to have a 16 bit DAQ with which I could just about measure signals using the 10 V range - as you would need to remove the DC offset somehow to read with a 5 V DAQ. I was planning on using a nice steady voltage regulator opposing the load cell until I found my DAQ was capable of handling the measurement. On the plus side, DC performance was now no longer affected by the amplifier's frequency response
So, tl;dr - get another excitation source and remove the DC offset voltage if you want to measure in DC coupling.
CLD

USB 9234 coupling settings in Mac OS X Labview?

Hi folks,
I have Labview on OS X here connected to a USB-9234. I'm just thrilled to see this hardware supported on OS X; NiDAQmx Base works great with it. However, I can't for the life of me figure out how to set the AC/DC and IEPE settings. I noted that the readme file references these coupling parameters as "properties". How do I set properties for this device? Any general pointers would be deeply appreciated.
Regards,
Tom
Solved!
Go to Solution.

Hi Tom-
I'm glad to hear you're seeing good results with your USB-9234 and NI-DAQmx Base.
In order to adjust the coupling and excitation settings, you will have to use the new (as of NI-DAQmx Base 3.2) NI-DAQmx Base Properties feature for LabVIEW. The properties interface was one of the last features we implemented for the NI-DAQmx Base 3.2 release that we are planning to potentially add more properties to and fully document in a future release. However, I made sure to add the excitation and coupling properties for the USB-9234 since those are such differentiating hardware features.
You can't find the properties VIs on the NI-DAQmx Base palettes in LabVIEW, so you will have to browse to them. They can be found in Applications::National Instruments::<LabVIEW dir>::vi.lib/_DAQmxBase/Internals/Properties. You will want to use the DAQmxBase Get/Set Property VIs found there.
For the USB-9234, you can either specify settings for all channels (by leaving ActiveChannel unwired), or you can specify settings on a per-channel basis by wiring a string to ActiveChannel that descibes the channel you want to use. Note that you can only specify ActiveChannel in the form "DevX/aiY", so you might need to call the VI multiple times to set properties for various channels.
One other catch with the USB-9234: you can not use IEPE excitation when DC coupling is enabled. Because of the way we implemented the properties interface, settings are immediately validated when they are adjusted. So, if you want to disable IEPE excitation for a channel you will have to first switch that channel to DC coupling. The order of operations is important, and you will be presented with a descriptive error if things are done out of order.
One other caution- the coupling and excitation settings do not take effect immediately when they are set with the properties interface. Instead, they take effect when DAQmx Base Start Task is called. You also can not update coupling or excitation while a task is running, so you would need to call DAQmx Base Stop Task, adjust properties, and then re-start the task.
I added property settings to the ContAcq&GraphVoltage example (attached here, in LabVIEW 8.5) and also took a couple of screenshots in case you are using a different LabVIEW version.
Please let me know if you have any other questions.
Message Edited by Tom W [DE] on 01-20-2009 10:09 AM
Tom W
National Instruments
Attachments:
Cont Acq&Graph Voltage-Int Clk(mod).vi ‏47 KB
Picture 1.png ‏10 KB
Picture 2.png ‏11 KB

Résolution carte NI 9234

Bonjour,
J'ai une carte NI9234 que j'utilise pour acquérir une sinusoide entre (-200mV; 200mV)
J'utilise pour acquérir mes échantillons, la fonction DAQmxReadBinaryI32. Pourriez vous me dire comment sont organisées les données dans le buffer de lecture ?
Les 24bits que je lis (Résolution de la carte) sont ils bit de poid fort à gauche ou à droite ?
J'utilise la fonction DAQmxCreateAIVoltageChan pour créer ma voie de lecture. Quelle min et max je doit mêttre pour avoir la résolution la plus précise ?, Comment cela influence les données que je lis ?
Merci d'avance pour vos réponses,
Cordialement,
Stéphane

Bonjour,
En réalité, le 9234 ne possède pas de buffer, c'est plutot le chassis l'utilisant (cDAQ, USB/ETH 1 slot etc) qui en possède un.
Maintenant, il n'y a pas vraiment d'utilité de savoir comment chaque bit est placé, DAQmx retourne les valeurs directement interprétable.
Maintenant si vous voulez récupérer du RAW (la valeur sur un I32, I16 par ex.) il faudra comme je l'ai dit, reconvertir les valeurs dans la gamme voulu.
Cad par exemple pour un +=5V la valeur maximale relative du I32 = 5V et la valeur minimale négative du I32 = -5V.
Ou alors vous pouvez aussi récupérer la valeur directement convertie sur un float via DAQmxReadAnalogF64 par exemple.
Dans tous les cas, il n'y a pas besoin de venir jouer avec les octets/bits renvoyés.
Pour toutes autres précisions et exemples vous pourrez vous référer au manuel de référence C de DAQmx:
NI-DAQmx C Reference Help
http://digital.ni.com/manuals.nsf/websearch/6A79EF4F9F30AFC086257A4400600861
Aussi, si ce n'est pas déjà fait, installer le support de DAQmx pour les langages textuels qui vient aussi installer des exemples C, .NET etc:
Installing NI-DAQmx Examples for LabWindows/CVI
http://digital.ni.com/public.nsf/allkb/BA4DF79463C884BD86256E0B00813E1E?OpenDocument
que vous retrouverez alors ici:
Location of ANSI C NI-DAQmx Shipping Examples and DAQmx Library File for Windows
http://digital.ni.com/public.nsf/allkb/FB26BDA52FFFD4EE86257124005C36C3
Vous trouverez facilement des exemples d'acquisition prêt à l'emploi, qui vous aiderons à démarrer.
Cdlt
Victor F. | Application Engineer
Certified LabVIEW Developer | Certified TestStand Architect
National Instruments France

CompactRio 9074 y ni 9234

Hola, estoy instalando compactRio 9074, pero al momento que estoy solicitando el ni 9234 no me aparece como device de opcion en la pantalla de MAX,
no se si se tiene que instalar con anterioridad o solo se inserta en el compactRio, al igual intente mandarlo llamar desde labview pero me marca NO DEVICE
Solved!
Go to Solution.

Hola
Las tarjetas de la serie C conectadas al cRIO, como la 9234, no aparecerán debajo de Devices and Interfaces de MAX. Siempre y cuando puedas ver el cRIO en MAX con la leyenda "Connected and Running" no tendrás ningun problema
PAra poder tener acceso a ellas debe de ser mediante el Distributed System Manager o desde LabVIEW.
Desde LV deberás crear un nuevo proyecto, y después agregar el target . (click derecho al proyecto>>New>>Target &Device. mDesde ahí podrás seleccionar el 9074, tranajar con el ScanInterface y esto de manera automática descubrirá los módulos que estén conectados al chassis.. aquí un ejemplo
Para hacerlo desde DSM (distributed system manager) sigue este tutorial.
Espero esta info te sea útil
Saludos

Format donnée brute NI 9234

Bonjour à tous,
Voilà mon souci :
J'enregistre un son à l'aide d'un micro et de la fonction DAQmxReadAnalogF64 je transfert ensuite ces données dans un fichier .raw
Mon souci est que je souhaite avoir des données sur 32Bits car j'ai un algorithme de traitement qui travail sur des données 32Bits et non 64Bits.
Je me suis donc orienté vers la fonction DAQmxReadBinaryI32 permettant de lire les données brutes de la carte au format 32Bits mais ces données ne sont pas à l'échelle et je ne peux donc pas les enregistrés directement dans un fichier raw.
Je me poses donc les questions suivantes :
Quel est le format des données brutes de la carte NI 9234 ?
Comment puis je transformé mes données brutes en format raw ?
Merci pour vos réponses,
Cordialement

Bonjour,
Afin de pouvoir répondre correctement, il faudrait quelques précisions :
Ton algo travail sur des données 32 bits, mais ça ne suffit pas. Un i32 et un sgl sont codés sur 32 bits, mais le premier code des valeurs entières entre + ou - 2147483647 alors que le second code des flotants. Le premier te permet de récupérer les données brutes sans mise à l'échelle, le second te permet de récupérer directement les données à l'échelle.
Je ne connais pas le format .raw, quelles sont ces spécifications ? En fonction de cette réponses tu pourras décider de la meilleure manière de récupérer tes données et d'effectuer une mise à l'échelle (si nécessaire) avant écriture dans le fichier raw.
Cordialement,
Olivier JOURDAN
SAPHIR | Certified LabVIEW Architect | Topaze on NI Community | LabVIEW add-ons on NI Community | Follow me on Twitter

Accéléromètre NI 9234

Bonjour,
J'ai un petit problème, Voilà, j'utilise actuellement un module Ni 9234 avec le toolkit "son et vibration" pour effectuer de l'analyse modale.
J'ai tout d'abord utilisé un programme dérivé du Vi "Impact test" pour effectuer des mesures au marteau d'impact et cela marche à merveille ( Utilisation d'un marteau: Stimulus, et d'un accéleromètre: Response).
Mais j'aimerai maintenant faire de l'analyse modale en faisant une acquisition en continu avec uniquement mon accélèromètre, et là j'utilise les VIs, compatibles avec le module 9234, présent dans le dossier "Mesures de fréquences FFT" de "son et vibration" mais je n'obtient plus rien (test effectué sur une boite de vitesse, nous n'obtenons que du bruit).
Pouvez vous me guider, m'expliquer ce qui ne fonctionne pas ou encore me diriger vers les VIs correspondant, sachant que je suis actuellement en fin de stage de 4A et que je n'aurrai pas le temps d'effectuer un nouveau programme.
Merci d'avance
B. CHARLES

Hello,
You are currently on the English section of the forum.
If you want to speak in french, please see the following link: french section
For your issue,did you try a simple analog acquisition to check that your accelero is running fine?
Also, did you try changing the slot of the 9234 module in the cDAQ chassis?
Regards,
Jean-Philippe C.
National Instruments France

NI 9234

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