Long term analog signal acquire

hi.
i got NI-USB6259 with signal express 2.0, and i need to acquire (and save to a file) 4 analog inputs at 200KHz for at least 20 seconds.
the device by itself canot acquire such mass of acquisitions.
i had a labview base software that can acquire the signals and writes the buffer contant to a file, each time it was full.
but how do i do that with signal express?

Hi Ofir,
One thing to keep in mind is that the performance you will be able to get out of this type of acquisition is system dependent. Because you are acquiring at a fast rate on multiple channels, the buffer that DAQmx allocates in your PC memory will be filling up at a very fast rate. Depending on your system, it would be likely that you would run into an overwrite error (DAQmx error -200279), where samples are overwritten in PC memory before they can be retrieved by DAQmx and written to file. Ways to prevent this error are to sample at a slower rate and increase the number of samples to read (in a continuous acquisition, this is the number of samples that the DAQmx Read will retrieve from PC memory on each iteration).
In general, the TDMS format is going to be your best bet because it is a binary format and is optimized for high-speed acquisitions. Once the acquisition has completed you can right-click on the log file and either convert it to an ASCII file or export to Excel. There is a KnowledgeBase article here with some pointers on how to optimize SignalExpress for acquisitions such as what you are trying to do.
Regards,
Andrew W
National Instruments

Similar Messages

How should i do?when i use the sc2345 for analog signal acquired!

please help me！
I have to use the sc2345+NI6221 for analog signal acquired. but i don't have a analog input module such as SCC-AIXX.
So I want to pass the signal to the DAQ device. how should i do to connect the wire on the sc2345？
how can I use the sc2345 for a pass connector？
Thank you very much and look forward to your reply...
Solved!
Go to Solution.

What kind of signal do you want to acquire?
If it does not need any conditioning, then, you can connect the signal to 6221 with a terminal block such as SCB-68.
Best regards,
NISH AE Haiping.Fei

Analog Signal Acquiring Problem

Hi, I'm using a DAQCARD-AI-16XE-50 for acquiring 6 Analog Signals Channels @1000Hz. At the first time I used the program that labview has as default by following "Labview->Daq solutions->Program the input scaling myself->custom daq solutions->Analog input->Acquire continuosly to spreadsheet". I can use this program on my laptop (Toshiba Satellite 4090CDS @300MHz and 64Mb RAM but not in my desktop Pentium IV @2,6GHZ. Do you have a clue?
Thanks
Maria

Hi Ben, I'm a new user of Labview and what I did is to use the default program for acquiring analog signal that Labview has in Labview->Daq solutions->Program the input scaling myself->custom daq solutions->Analog input->Acquire continuosly to spreadsheet.
I have been using this program for over a year and I've acquired lots of data with no problems at all in my laptop and my AMD k6-2 @ 450MHz old desktop and now that I have improved my computer to a better one is not working!
I just want to save some data @1000Hz of sample frequency. Normally I get around 79200x6channels to after analyze it with Matlab.I don't mind saving it after all the proces of acquiring is finished, so if you think that could be the solutions tell me what do I have to ch
ange in the file. But again, I don't know how to use labview, i'm new on this.
I've copied it to an image. Hope this help!
Thans again,
Maria
Attachments:
program.JPG ‏101 KB
configured_channels.JPG ‏54 KB

Trigger an Analog Signals Acquired Continuously

Sto acquisendo un segnale periodico tramite una DAQmx e devo triggerrare questo segnale.
Il mio problema sta nel fatto che devo poter impostare da front panel 3 parametri:
1 livello del trigger
2 isteresi
3 hold off

La scheda in questione non dispone di circuiteria per hardware analog trigger. Sostanzialmente questo significa che non e' possibile far partire l'acquisizione in seguito all'evento hardware scatenato dal superamento di soglia di uno dei canali analogici.
L'unica cosa che puo' pensare di implementare e' un conditional retrieval software. in altre parole, bisogna programmare l'applicazione per far partire una acquisizione bufferizzata continua in background e monitorare in parallelo il buffer di dati acquisiti per verificare quando si verifica la condizione di soglia desiderata con relativo ciclo di isteresi e decidere quindi di prendere i dati successivi e farne log a video o su file.
Questo Esempio puo' essere usato come punto di partenza per sviluppare il codice. E' necessario sostituire il clock esterno che questo esempio usa con il clock interno della scheda (Timing configuration) e quindi implementare il codice per gestire isteresi e holdoff.
Saluti
AlessioD
NI

How to input/output a digital signal and acquire an analog signal at the same time?

Dasylab, version: 8.0.04
Acquirement Card: PCI1002L
When I use DasyLab to acquire the analog signals is no problem without digital inputs and outputs,
and when I use DasyLab to input or output a digital signal is no problem also, but when I do that at the
same time, DasyLab tell me the rate is too high and stop.
so, I searched the manual book1 (user guide) for that, it showed me :
To internally equalize measurement time and system time in the analog input, digital input and counter
hardware modules, use the following settings:
   Synchronization: PC Clock
   Sampling rate: <= 5Hz
   Block size: =1
the problem is, if I set the Sampling rate to 5Hz, the speed of the acquirement datas is not enough for my
application.
so, how to improve it? who can give me a example programm for me. thanks!
by the way, I come from China, my English isn't good, I'm sorry.
Allen, China.

Hi,
Have things changed over the years?
I need to syncronise a digital output (Modul NI9474) and an analoge input (AI-Modul NI9203) module. I need to measure time intervals from a flank in signal A to a flank in signal B. I would like accuracies of the order of 1 ms. Currently, the signals are not synchronised, with errors of the order of 2 times the block length (block size x sample rate), sometimes much higher. The best I got so far was a block size of around 20 with a sample rate of 1 kHz.
If I use the master and slave settings on the RTSL settings, my program doesn't run properly.
If I use digital signals for input and output, I can syncronise them with RTSL settings and everything is good, but I can't always do that.
Also, if I do anything in the GUI (such as scrollowing something or going to another window), my output gets screwed up properly.
1. What can be done to synchronise AI with DO?
2. Is there something that can be done to avoid messing up the output when something happens in the user interface? (I know that I am messing up the outputs as they make some valves switch and that is loud).
Thanks in advance!

How to acquire analog signal and send a TTL pulse at the same time based on PXI 6123

Hi,
I am using a PXI-6123 data acquisition card, as the picture show in the attachment ,I want to acquire the analog signal of ai0 through reference analog window and at the same time send a TTL signal to trigger my camera. I have tried two methods, one is using the DAQmx Export signal.vi another is using DAQmx connect terminals, but when the data acquisition card acquire the analog signal, the DAQmx Export signal.vi and the DAQmx connect terminals sometime can send an TTL pulse ,sometime can not.
I don’t know why? or some other method that can achieve my arm is appreciated.
Regards
chunlei
Attachments:
method export signal.vi ‏21 KB
method connect terminal.vi ‏36 KB
Send a TTL pulse.JPG ‏288 KB

Hi,
Have things changed over the years?
I need to syncronise a digital output (Modul NI9474) and an analoge input (AI-Modul NI9203) module. I need to measure time intervals from a flank in signal A to a flank in signal B. I would like accuracies of the order of 1 ms. Currently, the signals are not synchronised, with errors of the order of 2 times the block length (block size x sample rate), sometimes much higher. The best I got so far was a block size of around 20 with a sample rate of 1 kHz.
If I use the master and slave settings on the RTSL settings, my program doesn't run properly.
If I use digital signals for input and output, I can syncronise them with RTSL settings and everything is good, but I can't always do that.
Also, if I do anything in the GUI (such as scrollowing something or going to another window), my output gets screwed up properly.
1. What can be done to synchronise AI with DO?
2. Is there something that can be done to avoid messing up the output when something happens in the user interface? (I know that I am messing up the outputs as they make some valves switch and that is loud).
Thanks in advance!

Acquire analog signal with NI PXI 1042 with RT

HELLO,
Do you have an example of this program ??
I ACQUIRE a analog signal on the enter of the PXI and then i must to write it on the RT computer !!
Thank you for your help!

Hi,
You can find examples in the LabVIEW "NI Example Finder". You can access it in the LabVIEW help menu. Click on "Toolkits & Modules" then "Real-Time" to find RT examples.
Best regards.
Benjamin
Application Engineer
National Instruments

I am staying long term at a hotel. Is there a way I can boost the wifi signal?

I am staying long term at a hotel. Is there a way I can boost the wifi signal?

I think you may have better luck working with the hotel management and have them contact their wireless service provider to see if they can improve the signal in your room.
The only other option might be an external Wi-Fi antenna for your iPad ... but I'm not aware of anyone providing these at this point in time. Sorry!

Analog signal from PXI

Hi everybody,
I have a problem: I cannot acquire 6 analog signals with a PXIe 8135 with 4MS/s. I use two boards with 4 MS/s, 16 bits and 8 Analog Inputs. I use a subVI of SAMPLE CLOCK for configuration with this parameters, Continuous SIGNAL, SAMPLE RATE = 4MS/s ( see attachment ). With one signal is ok, but with 2 signals, i have an overload Memory Message.
Where is the problem in the VI?
Thanks for your help.
Attachments:
acq_and_graph.zip ‏165 KB
acquire&loggdata.png ‏230 KB

Quickly looking through your code now, try removing the "Number of Samples analog". Since you are using Continuous Samples, you are just limiting the buffer and also limiting how many samples you can read at a time.
But you might want to think about using Finite Samples. You know how long you want to log for and you know your sample rate. So why not just do the simple math and tell DAQmx to get that many samples? You can use the DAQmx Task Done? VI to see if it is done. That would be much simpler than checking the time that has elapsed.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

How to make a synchronous acquisition of two analog signals with a one channel DAQ ?

Hi !
It is the first time I use Labview. I have just made some easy VIs, and now, I do not know how to deal with my problem...
My problem : I have only one acquisition card (DAQ Ni 6034E) and I would like
to acquire simultaneously two analog signals. It seems to be possible, in a quasi-synchronous acquisition if the card acquires one point of the first signal, then the first point of the second signal, then the second of the first signal, and so on ... I thougth that I could made two sequencies with a VI of data acquisition in each sequency, with the AI MULT PT. But with this, I think that I will lose the precision of the sampling frequency. And I have to know the sampling fre
quency ...
Thanks for your help !
Carline

Hi Carline,
A PCI-6034E is a low-cost board, which only has one Analog to Digital Converter (ADC).
With only one ADC you can't acquire different channels at the same time. That's why you find a multiplexer before the ADC in this type of board. This enables you to acquire multi-channels at the same rate quasi simultaneously. The samples of the different channels will be interleaved as it is explained in the following knowledge base :
- http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/9379ea091c264b7c86256bc90082ca5d?OpenDocument.
With this method, the sampling frequency is the same for all channels. The sampling frequency of one channel is determined with the "scan rate" parameter. There is only a small delay between the samples
of each channels. When you perform an interval scanning acquisition, this delay depends on the "sample rate" that you specify. To have more informations about this terminology, please refer to the following KBs :
- http://digital.ni.com/public.nsf/websearch/4D1435DF82EF494186256D8A006DD6D4?OpenDocument.
- http://digital.ni.com/public.nsf/websearch/4D1435DF82EF494186256D8A006DD6D4?OpenDocument.
To easily perform such a multi-channels analog acquisition, you can use the VI named "AI Acquire Waveforms.vi". You also can use an example provided with LabVIEW. You just have to browse the NI Example Finder in "Harware Input & output >> Traditional NI-DAQ >> General".
Best regards,
Benjamin
National Instruments France

Synchronous acquisition 4 analog signal and independently count TTL impulse

Hello!
I'm have NI DAQ board PXI-6115. I have problem:
Need synchronous acquisition 4 analog signal and independently count TTL impulse. When value counter will, at example, 5000 acquisition must stop. I'm read program in LV 7.1 but have a problem. In HELP write:"You can create only one counter input channel at a time with this VI because a task can contain only one counter input channel. To read from multiple counters simultaneously, use a separate task for each counter". I make two different task, but error not disappear.
I don't know how escape this error?
Program VI with Front panel screen-shot in attach archive.
Message Edited by _Pavel_ on 05-23-2007 09:06 AM
Attachments:
Progr.zip ‏80 KB

Hey Pavel,
Thanks for contacting National Instruments support. Your program, in it's current state, is attempting to generate a finite pule train and count edges on the same card. Finite pulse generation is a two counter device, where one counter generates the pulse train and the other counter gates the generation, or goes high when the generation is to start and low when it is finishes. So no matter which counter you select for the count edges task you will get the error you describe.
Is it possible to use the pulses that you are counting as an external clock? If so then you could just generate 5000 pulses and you would only acquire 5000 samples.
I have attached a modified example from your code.
Let me know what you think. It only acquires 5000 samples as desired.
Regards,
Kenn North
Senior Product Manager - Search, Product Data
http://ni.com/search
Attachments:
Progr.vi ‏58 KB

Is there a VI availible that will allow one to interact with an analog signal

Hello all,
I am new to the sight and look forward to participating. I have a project that I’m working on and I would like to ask for your thoughts and direction if you’re willing. I have a few weeks left before completing an electronics program degree and Labview is one of the classes. The project I have chosen is to illustrate the differences between a micro controlled system and Labview controlled environment. I will be acquiring a signal through a ultra sonic distance sensor. The analog signal will be produced after which acquired through a SCB – 68 connector block and converted using the pci-mio-16E. The sensor operates at 40 kHz emitting a 5v pulse (burst) then falling to gnd for a short period followed by a 5v rise and staying high for a period of time waiting for the return of the frequency. This time period represents 3 inches to 27 ft in distance. I would like to interact with this signal through the distance period (portion) and output a string displaying a numeric value of the distance on the front panel obtained from an array built from different periods of the signal. I am not clear on what Labview function offers this type of control. I am hopeful in utilizing a vi or some type of trigger that allows me to build an array produced by some math functions. Any help would be appreciated.
Thank you, dhitch

First thank you for your response, I will have an opportunity to make a capture tomorrow in class. I believe I have run across the waveform measurement VI in my searches and am sure it’s a very good choice. The trigger VI you suggest, going by the name, should be my ticket. Would you imagine a delay or decreasing time after the capture, allowing the trigger VI time to respond to an output configuration be required?
If I remember correctly the sampling rate capabilities are 500K samples/ second with 12 bits of resolution and as I say that it seems some of the capabilities rely on the processing speed of the computer. I guess I will kick the tires tomorrow hey. There are 2 class periods remaining to finish our projects @ 2 hrs / class and my anxiety is a bit high. Wish me luck and thank you so much.
dhitch

Synchronize Motion velocity with DAQ analog signal

Hi Everybody
I am acquiring analog signals using hw trigger and external clock with C and A signals of a 1024 counts TTL encoder.
Now I want to measure the rotation speed of a shaft. I have a Flex-Motion board with which I want to read the velocity (or the same encoder), but I don't know how to synchronize each scan of the analog signals with the velocity signal for that instant.
I can´t use RTSI bus because my Motion board doesn´t have RTSI connector.
Software and hardware:
LabView 6i (v. 6.0.1.b3)
DAQ-Board: PCI-6023E, NI-DAQ 6.8.1, MAX 2.0
Motion board: PCI-FlexMotion-6C, NI-FlexMotion 5.0.1
Thanks a lot for your help.

Hi chia,
with the hardware configuration that you have, I think it´s not posible to synchronize both boards due to you cannot share the same clock source (not RTSI on the motion board).
http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/66e6f4ee7e0848d686256a55006...
Sorry for the delay :-)
Regards
DiegoM.

Ask the Expert: Demystifying Long-Term Evolution

With Rahul Pal, Arpit Menaria and Krishna Kishore
Welcome to this Cisco Support Community Ask the Expert conversation. This is an opportunity to learn and ask questions about evolution of long-term evolution (LTE) and the future with experts Rahul Pal, Krishna Kishore, and Arpit Menaria.
LTE, commonly marketed as 4G LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using a different radio interface together with core network improvements. The standard is developed by the 3rd Generation Partnership Project (3GPP).
Rahul Pal is a customer support engineer based in Bangalore, India. He has seven years of experience in the field of GPRS/UMTS/LTE technologies specializing in R&D and customer support. Rahul has worked with multiple vendors such as Nortel, NSN, and now Cisco, gaining expertise in packet core products such as SGSN and MME. Rahul has also worked as an escalation engineer handling customer escalations (technical troubleshooting and handling customer management). Rahul also has international experience of working directly with telco customers in the United States, Europe, and APAC and holds an engineering degree in information technology.
Krishna Kishore is currently working as a customer support engineer based in Bangalore, India, focusing on ASR5000/ASR5500, SAMI, and HWIC products providing support to 3G/4G mobility solutions deployed across the world. He has more than eight years of experience in mobility technologies such as GPRS/UMTS/LTE/CDMA, with experience in development and customer support. Krishna has worked with multiple vendor platforms such as Nortel, Hitachi, NSN, and Cisco. He holds a bachelor's degree in electrical and electronics engineering and CCNA certification.
Arpit Menaria is a customer support engineer based in Bangalore, India. He has been with the Cisco TAC for the past two and a half years (since July 2013) and has worked in FTS and TAC roles. Throughout his seven and half years of industry experience, he's worked for Ericsson and Tata Communications getting exposed to the telecom and Internet service provider environment. His technical skills span mobility, routing, switching, Linux, and Solaris. He has CCIE certification in routing and switching (written), RHCE, and WWSP mobility expert (written). Arpit also holds an engineering degree in electronics from the Indian Institute of Technology, Banaras Hindi University of Varanasi.
Remember to use the rating system to let Rahul, Krishna and Arpit know if you have received an adequate response.
Our experts might not be able to answer each question due to the volume expected during this event. Remember that you can continue the conversation in Wireless - Mobility, sub-community Other Wireless - Mobility Subjects discussion forum shortly after the event. This event lasts through March 14, 2014. Visit this forum often to view responses to your questions and the questions of other community members.

Challenges Faced by operators while deploying LTE Solutions
1.) No Global standards in LTE Spectrum Bands allocation and usage
Operators have to support range of spectrum bands to support. A lower spectrum band (e.g. 1800MHz) provides better indoor signal strength and travels further compared to one of a higher spectrum band (e.g. 2600MHz). However, the higher spectrum bands are better suited for covering densely-populated areas and managing heavy data volumes due to their larger bandwidth. lower frequency spectrums are more affordable to build and signals travel further, whereas higher frequency spectrums require a lot of base stations to cover a similar distance. This could very well be another possible reason why different Operators around the world use different spectrum bands, besides the obvious fact that they are also limited by the availability of these bands.
2.) Building a New or Converged Network and Backward compatibility with Legacy Networks:
Some Operators will build a completely new 4G network along the existing networks. Other Operators will create a converged network, where they try to make the different generations of technologies work together. In both cases, the process is highly complex and cost intensive. The transition to 4G network will require new radio access technology and core network expansion, while maintaining existing 2G/3G networks alongside the new 4G network will result in additional burden on Operators.
LTE is flat IP architecture so there is a need to create high capacity IP core network to connect MME(mobility management entity) ,S-GW,P-GW. All the interworking nodes including non- 3GPP systems is to be re-dimensioned. Backward compatibility is a very complex task during LTE deployment.
3.) Return on Investment (ROI) on 4G LTE
The migration to LTE or upgrading of existing mobile networks will incur high costs. Moreover, 4G LTE is expected to disrupt the traditional business models of Operators: voice calls and SMS. On LTE, we still don’t have Voice call Support and Proposed launch of VoLTE is still not widely deployed and in testing phases at many places.
With faster mobile data connectivity, consumers will be more inclined to use services and apps such as Skype and Whatsapp for communication. This change in consumer's usage behaviour will pose a challenge for Operators to profit from their investments in 4G networks.
4.) Operators have to devise new Data plans
To justify the investments in the new 4G networks, Operators have to change their data price models.
First, Operators will charge higher prices for their LTE offerings compared to their existing mobile data plans and maintain a higher quality of service to justify the higher Pricings.
Second,. They should implement "pay-for-what-you-use" pricing models, where consumers are charged based on their usage behaviors.
Third, Operators can adopt a value-based pricing model where consumers can pay a premium for a better experience, raising the possibility of introducing tiered service levels that guarantee certain connection speeds.
Biggest problem is customer cannot relate to all data plans and have to constantly monitor data usage to ensure that they receive high data speeds.
5.) Security Concerns from Untrusted Domains
While operators can theoretically benefit from reduced latency and greater ease of management within the LTE architecture, there is a very real possibility that overall LTE performance will degrade due to the high volume of transactions required to ensure that high levels of service quality are maintained and proper policy control decisions are implemented. Operators face significant challenges in the area of network security as traffic in emerging architectures is increasingly likely to flow within spheres of "trusted" and "untrusted" networks. framework allows operators to handle security gateway functionality.
Within the LTE network elements, including the ability to implement IPsec — the IP network security standard. Operators facing this new, unfamiliar environment face a key choice: whether to rely on the functionality provided within the standards-defined LTE network elements to address security and other requirements or whether to adopt standalone solutions. Cash-Strapped Operators might Opt for LTE solutions as they need not invest separately in Security Devices and functions.
6.) True 4G Global Roaming is not possible unlike 3G
Due to the lack of harmonization of LTE spectrum bands across different countries, it is almost impossible within the near future to support LTE global roaming.
To use a LTE device for data roaming, based on the current worldwide spectrum usage, the device needs to support at least 15 bands. Supporting so many band on LTE handset is not possible. So 3G data roaming for international traveler is here to stay for very long time still we standardize LTE Spectrum Bands Globally

Long term experiment application error

Hi I am running a long term experiment where I am continuously reading in and plotting/saving Bluetooth Data, using a LabVIEW executable. After about a day, a pop up appeared titled:
"SMessaging.exe - Application Error"
Application has generated an exception that could not be handled.
Process ID=0xe4c (3660), Thread ID=0xe7c (3708)
Click OK to terminate the application.
Click CANCEL to debug the application.
Nothing appeared in my Error Handler list, however when I cleared the pop-up error and ran the vi again, Code 1: source - ??? in btnew.vi appeared and the vi wouldn't run, I had to shut down the computer.
Is it something to do with the .exe build that I made? I am running Windows XP with the LabVIEW runtime.

Well, two things stand out to me:
1. Your inner loop has no timing. That means it is going to run as fast as possible, taking up 100% of the CPU until it is told to stop. And it is only told to stop when you get an error. You cannot stop it without hitting the Abort (stop sign) which screws up everything. And if anythng else comes along that wants to use CPU time, they're going to have to fight for it.
2. Your outer loop also cannot be stopped without hitting the Abort, because you have wired the F to the stop loop terminal. Again, not good.
I have no idea how you can stop your executable without just turning it off (might even have to go into Taskmanager to do so, but you'll have to fight for CPU time).
You would be much better off putting some reasonable timing in there so you could at least stop things manually, as I assume you are going to want to stop the program sometime, unless the Bluetooth signal you're reading is actually a "5 minutes to Doomsday" signal and you want to be sure you are ready.
The comments by others about what might happen when the PC sleeps/hibernates/etc. are also relevant, unless you have disabled this.
Programs are much easier to troubleshoot before they are compiled into an executable.
Cameron
To err is human, but to really foul it up requires a computer.
The optimist believes we are in the best of all possible worlds - the pessimist fears this is true.
Profanity is the one language all programmers know best.
An expert is someone who has made all the possible mistakes.
To learn something about LabVIEW at no extra cost, work the online LabVIEW tutorial(s):
LabVIEW Unit 1 - Getting Started
Learn to Use LabVIEW with MyDAQ

Long term analog signal acquire

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