Multi-buffered acquisition with digital trigger

I have a PCI-MIO-16E1 and I need to do three channel (250KHz/channel - ~400 scans/trigger) multi-buffered acquisition with digital trigger (trigger => 30 Hz).
I could not find any example of multi-buffered acquisition. Could anybody help me?

Hello,
I assume that you are refering to a retriggering setup where each time you recieve a trigger you take 400 samples on each channel at a rate of 250kHz per channel (total scan rate = 3CH * 250kHz = 750kHz).
In order to keep the system hardware timed you can use the two counters on the board to produce a retriggerable pulse train that will act as your scan clock. For example each time the counter recieves a trigger it will output a clock signal of 750kHZ with 400 or so pulses in order to take ~400 scans/trigger.
This clock signal can then act as the scan clock for your 3 channel analog input operation.
Now we have to figure out how to set up the retriggerable pulse train from the counters and have the analog input use the counter output as a sca
n clock.
Good thing there is an example that is already written
http://zone.ni.com/devzone/explprog.nsf/6c163603265406328625682a006ed37d/aab61e455564a04d862568930018e725?OpenDocument.
Good Luck.

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So every 4 msec you get a trigger signal that should initiate a 2 msec acquisition (1000 samples at 500 kHz sampling rate)?
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The goal is to make sure the timing is handled in hardware so you don't miss triggers while doing the software reprogramming. AI Start would be called only one time prior to your loop, and only AI Read would be calle
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Just be careful about your timestamp info. The analog acq. task won't have any "awareness" of time intervals between samples. It'll be up to you to slice up the data into appropriate chunks. You can probably do this by simply requesting the right number (1000) from AI Read.
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How do I use bidirectional buffered acquisition with handshaking on the 6533

I would like to use the 6533 board to generate digital patterns from a spreadsheet file (transfered to a buffer) with handshaking on ports A and B. At the same time, I need to acquire digital patterns on ports C and D, also with handshaking, and transfer it to a separate buffer. I already have the two tasks working separately. However, when I put them togheter in the same Labview program, the acquisition seems to work, but the pattern generation doesn't. I also get the "Error - 10409 occured at Digital Group Config", saying that the specified group is in use.
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In the DIO Config.vi you must explicitly set the 'Group' parameter for both processes (Input and output) to different values, otherwise the defaut 'group 0' will be found in use by the second DIO config executed.
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Solved!
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Hi DB,
A good example for this application is a DAQmx shipping example in LabVIEW. In LabVIEW, navigate to Help»Find Examples»Hardware Input and Output»DAQmx»Analog Generation»Voltage»Cont Gen Voltage Wfm-Int Clk- Dig Start.vi.
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For a meagre 1 channel acquisition at a sample rate of 100 Hz and buffer size of 1000, I get this message:
"Warning -10026 occurred at an unidentified location.
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My favorite way to get this error is to accidentally wire something to the "number of buffers" input on the AI Config VI. This should be left unwired most of the time. You can also get this error if the buffer size is invalid. This would be less than 3 or greater than 2^24 for your board. See KB 1JAKLN6Q for more information.
Finally, as a check I would run one of the shipping example programs to see if you don't get the same problem. Then you can compare your program to it. Try "Acquire N Scans.vi"
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http://www.ni.com/support

Multibuffer acquisition with PCI-6115

I am trying multi-buffer acquisition with a PCI-6115 board. I seem to get an error (-10026) that suggests that this board does not support multi-buffer acq. does anyone know if this is so?

By multi-buffer acquisition, do you mean doing buffered acquisition for different channels simultaneously? If this is the case, PCI-6115 boards allow this since each analog channel has its own DAC.
Are you trying to do Analog Input or Analog Output?
What value are you putting as buffer size?
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Digital stimulus-frequency response: Need to drive with digital output trigger. Using counters for response.

I need to drive stimulus-response with a software driven digital trigger and NI-TIO counter based response. No analog I/O is really relevant, although I have a PCI-6035E multi-function DAQ as part of my gear. I intend to use the analog, but its timing is non-critical and can be software timed.
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while( enabled )
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I have made some failed attempts which relied on software to sync up the trigger and the response frequency acquisition. This is definately flawed. I need to start the counting right after setting the digital output trigger, and stop the count after a fixed interval for frequency calculation.
I am having trouble working through the signal routing to get the timing to trigger off the digital stimulus output pulse.
Any help would be appreciated
Thanks,
Joe

Joe
What are you using the trigger from the 6035E for? I do not know what you mean by, "to trigger frequency countes."
If you are having problems just routing the signal to the 6602, here is a vi that shows you how to route a signal through the RTSI cable to use as the source of a counter.
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Attachments:
Route_RTSI_to_Source.vi ‏67 KB

How do I use a push button digital trigger with my 6034E DAQ board?

I am only a Lab View toddler.
I am currently using a push button, wired to PFIO/TRIG1 and DGND, with a anolog trigger. However noise is causing my program to be triggered. I was told that a digital trigger would help to reduce the random triggering. How do I create a push button digital trigger?
Thanks

implement a schmitt trigger.
Struggling with Labview wrote in message
<[email protected]>...
>I am only a Lab View toddler.
>I am currently using a push button, wired to PFIO/TRIG1 and DGND, with
>a anolog trigger. However noise is causing my program to be triggered.
>I was told that a digital trigger would help to reduce the random
>triggering. How do I create a push button digital trigger?
>Thanks

How to use digital trigger with analog I/O

How do I program analog input and/or analog output to start on a digital trigger (PFI pin) on PCI-4451/4551.
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I have not been able to find any LabVIEW example that shows how to use PFI pin as trigger input.
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Kind regards / Med venlig hilsen
Torben

Hello
The PCI-4451 does not have any PFI lines. If you look at the user manual in the link beneath you will be able to confirm this by looking at the connector signal discriptions. The same is valid for the PCI-4451
http://digital.ni.com/manuals.nsf/websearch/6A32358C53BB15F086256660007392DC?OpenDocument&node=132090_US
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Hardware digital trigger to start stop continuous analog acquisition

Hi I have seen the following example to use digital trigger to start and stop for finite number of samples. The example names is (DigitalStartandStopTrigger.vi)
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HI tintin_99,
The way that example works (by modifying the read position of the buffer) essentially performs the same operation that the continuous samples mode does. That is to say, it is already a continuous acquisition.
The article below explains this in more detail, and the reasoning behind specifying buffer size manually and other tricks used. You may have already visited it in order to get the example VI, in which case it may be worth another read over.
http://digital.ni.com/public.nsf/allkb/BA775B0E445BFA79482571FE0032CCEB
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Can PCI 6031E handle multi-buffered data acquisition

If so can anyone send me some instructions or LabView code. Thank you in advance.

Greetings,
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In addition to LabVIEW itself you will find our web site's Developer Zone extremely useful.
Development Library
http://zone.ni.com/devzone/devzone.nsf/6ae7945502d89dea0625685500506e1f/4d58b1b80ec41ef70625683f006e1d6d?OpenDocument
Regards,
Justin Britten
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Nati
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Multi-record continuous acquisition with PCI-5112

Hallo!
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In "niScope EX Multi Record Fetch Forever.vi" shipping example (LV 5.1), it seems to stop when "loop index" rises to "number of records -1" value.
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If I've well understood, I could modify the loop condition, by erasing the check on loop index, and by wiring "loop index"mod(N), to "fetch record number" attribute (let's define N as "number of records"). So I could continuously fetch the records 0,1,..,N-1, for the first cycle, and again 0,..N-1, for the second cycle, and so on.
OK! I think that the contents of a reco
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NatRob,
It sounds like you are on the right track. The only thing keeping this from running continuously is the comparison of "loop iteration + 1" to the "number of records." Other than that, the loop should only stop when an error occurs or hte Stop button is pressed. Just erase the greater than comparison and the boolean used to stop the loop and it should work.
Regards,
Chris Drymalla
NI Applications Engineer

Flexmotion single point acquisition with Analog buffered acquisition

I am trying to read the ADC's with a 7344 motion card using a looping single point acquisition equivalent to 50Hz. This is occurring at the same time as I am performing a buffered analog acquistion on a PCI6023 E-series at 1000Hz.
The values from the ADC's are stored in an array, but when I view this array there are hardly any data points, maybe about 20 in total.
I am guessing that it is because of the buffered acquisition, but can anyone help me understand this problem a little better? Can I accomplish what I have described?
Thanks
Chris

I checked and the Read Position VI loop runs properly while the motion profile is running (without any analog acquisition through my 6023E card).
Likewise, with no read position loop, all the analog acquisition with motion runs properly.
I have attached a simpler example that I tried, so that there was no triggering involved. The analog acquisition runs, and I find that the Read Position VI loop only starts displaying once the analog acquisition is finished (after 2000 samples/ 2 seconds).
It seems that it cannot do the two processes at once and that the analog DAQ on my 6023E card has priority over the Read position loop????!!!!???
The example is in LV5.1.1 format
Any help would be much appreciated!
Chris
Attachments:
simultaneous_DAQ_on_6023E_and_reading_7344_flexmotion_(simple_example).vi ‏149 KB

Getting timestamp for analog acquisition with NI6110.

When I use the AI Read VI to get a waveform containing a sequence of scans, the waveform has a timestamp that presumably represents the absolute time of acquisition of the first scan as measured using the system clock. (I can't find any documentation on this, by the way. Where is this documented?) I notice that the AI Read VI can alternatively be used to return a "binary" array of measurements. For various reasons, I prefer to use this form of the AI Read VI, but I'd also like to get the timestamp that would be included in waveform returned by the waveform version. However, I don't want to call the AI Read VI twice, one time to get the binary array and a second time to get the whole waveform just so that I can g
et the timestamp. Is there a way to get this timestamp without getting the whole waveform?
Thanks,
Neal.

Thanks for replying.
I'm performing digitally triggered, buffered data acquisition with my 6110E, with the possibility of pretrigger sampling. The data I'm acquiring may extend several second before and after the trigger. Furthermore, my application may call the AI READ VI at some unpredictable time several seconds after data acquisition is complete. I'm assuming that the timestamp that would be returned as part of the waveform by the AI READ VI (whose exact nature appears to be undocumented) is calculated from the system clock at the time at which the digital trigger occurs, and wouldn't depend on when the AI READ VI was called. The article you referenced doesn't tell me how to do what I want. I want to get EXACTLY the timestamp that the AI READ
VI would include with waveform data, were it asked to return waveform data, but I want to use it to only return binary data. To the best of my understanding, the method described by the article for a obtaining a timestamp when binary data is retrieved provides no guarantee that the timestamp obtained will be the same one that would be returned as part of a waveform by the AI READ VI. Indeed, using the "Get Date/Time In Seconds" VI would seem, under the circumstances in which I would use it, to produce a timestamp that differs unpredictably from the time of the trigger by seconds.
Thanks,
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Important question: I have got a PXI-4472 and I am able to do single-channel acquisition. How does multi-channel acquisition work?

Look at the VI: it is quite eleborate, but the crucial point is Data Acquisition and Trigger&Gate (and, consequentely, Write to File operation).
I can add plot on the Waveform Graph DATA, this is rather easy, simply adding the channel numbers in the channel control (es. writing 0,3,7 will collect data from the three channels).
First question: is this operation of adding plots correct?
Second question: does the sampling rate dwindle when I consider multi-channel acquisition? I mean: 1 channel-->100KHz ; 2 channels-->50 KHz
More over, and MORE IMPORTANT: is it possible to set different trigger conditions for different channel
s? How can I control this operation?
Third: can you have a look at the VI as all (the appearence, the functionality, the logical sequence...). I am looking forward to get your advice. In particular:
Look at the frontal panel: what do you suggest to make it "smaller"? More tab controls?
Look at the Block Diagram: do I have to connect ERROR IN and ERROR OUT to every suVI or function that makes this connection possible (as Trigger&Gate and Write File)?
Attachments:
Start&StopTrig_SpectralMeas_style+image.vi ‏700 KB

First: yes, the operation is correct.
Second: yes again. When you consider a multi-channel acquisition, your sampling rate must be shared among the channels.
Third: when you specify a list of channels you want to acquire from, the channel considered for analog triggering is the first you put in the list.
Connect the error clusters whenever you can,in particular when you are dealing with I/O operations.
Bye!

Multi-buffered acquisition with digital trigger

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