Several channels AND DAQ

Similar Questions

• At the same time Record several channels in DAQ

  I'm currently configured to play two channels in data acquisition using DAQ Assistant. I wonder what would be the best way to go on the sampling of these channels at the same time, or as close as possible. The vi that I currently use is attached.

  Thank you

  Sawyer

  DAQmx manages the calendar under the hood and does it quite well.  If you want to change advanced sync settings you can, but of course, you will have to abandon the DAQ ASSistant and write a LabVIEW code.

  I assume you are using a multiplexing card right?  The only real solution for true simultaneous sampling is to buy a card that has several a/d converters like the S series cards.

  For the second poster: you do not have the same problem as the op.  It can be implemented in multiple channels.  If you want to help, you must provide further information that "it gives an error.

  EDIT: I bet you are trying to use separate tasks for each entry, aren't you.  If you do, you'll get a resource conflict error.  You must use a SINGLE task and set up several channels in this task to collect more than one signal.

• several channels in daq assistant

  Hi guys,.

  My first post on this forum, would appreciate some advice.

  I use labview 8.2 with PCI-6071E acq. card.

  I'm observing unexpected behavior when you try to read analog data on my card.

  If I define in the daq assistant, one way to read, everything is great, and the data is ready, as planned. I can see it in the preview window (explicit task)

  When I open the daq assistant.

  But, at the point where I have to add a channel more (from the same physical pci-6071e card), my measurements are totally fake - I get a strange signal...

  The sampling rate is more than enough (I enjoy with 64khz a 1 kHz signal arriving at one of my channels).

  What I'm missing here?

  Thanks for any advice you may have.

  Lenny

  With the generator of signals (output TTL) or the PCI-6071E AO the gsignla is NOT differentiated. Use one of the configurations of single entry completed.

  The Earth all unused inputs.

  Lynn

• Use the listbox control to select several channels and display on the chart

  Hello everyone!

  I have a problem using the ListBox selection mode 1 or mode items. I have 6 channels of data, and I have a 2D chart. I am able to reterieve the signal names in the list box, but I want to be able to choose one or more signals to display on the chart. I used the table to index my 2D data are connected and then the output of the index table is connected to the graph. I had to use the listbox control as an index for the table to index and display the data in the index selected for display on the chart. I used lisbox as the value property nodes, the line active and all but not able to display signals on the graph. I have attached a code example to show you what exactly I'm looking.

  Any suggestions will help a lot.

  
  

• FFT on several channels in FPGA

  I have a client with a 9076 (Spartan-6 LX45) who wishes to perform the FFT on several channels of a module of 9205.

  I never run FFT on several channels and never run out of space on the FPGA before, but I strongly suspect that this could change that.  Before I start to code this and play, someone can experience with this scenario - that offer you an optimal architecture / let me know how many channels can I expect to treat?

  Hey Jed,.

  As someone who has done a very similar application, but with the DC/RMS measurements, I can say with confidence that Yes, this is going to change that... How many channels your client wants to do and what kind of flow? I was able to get up to 64 is going, but it took most all of the fabric, and I had to write my own calculation of DC/RMS multiplex VI. So under a flow of course (I think we had each channel was updated to 1 Hz with 1000 samples per channel). Therefore, when writing a VI that multiplexes across all channel data, you could theoretically get many channels out there, but you sacrifice a flow.

  Basically, I modified the existing Express VI to store its State in BRAM between each call and he's travelled to the number of channels * samples I was doing. Not terribly difficult, but your time trying to find a good balance for the given application.

• How to parse the input data of several channels simultaneously via an NI USB-6251 box by use of a single DAQ Assistant?

  I did separate VI for reading signals from several channels on a map of NI USB-6251.  I would like to combine these in a VI VI alone so that they can run that at the same time, however, there is an error if there is more that a single DAQ Assistant in the same--> error-50103 VI was held at DAQmx controls Task.vi:32 (the specified resource is reserved. The operation could not be performed as indicated.)

  All the inputs of channel must then be read in with a single DAQ Assistant, but all of the data on different channels are not separated.  Can save this data in a matrix or otherwise manageable which allow to facilitate the analysis of the data from the separate channel entries?

  I tried to view the data in a file of measures, but then when I tried InPort data, I could all the data I wanted.

  Hi AggieGirl,

  Good afternoon and I hope that your well today.

  First of all, you will not be able to have more than one DAQ Assistant by input analog or analog output task because the device has only one of each. So, you must have a DAQ task to HAVE and AO. (This is not the case for DIO static).

  There is far from split signals using the express VI - signal splitter.

  When you say you saved this file and it does not work, how it did not work? The Express VI - save a file of measures needed to manage multiple waveforms. Can send you your code & explain more about what was not OK on the file?

  

  Thank you

• DAQmx create several channels of

  I downloaded the program entry OR bridge-continues and tries to modify it slightly to allow several Wheatstone bridges to connect. Currently, it has the ability to connect to a single channel but don't not to acquire information from several channels simultaneously. All information regarding the shunt calibration, bridge information and waveform graphic output remains the same. Ideally, the program displays the greatest value in the final waveform graph, but it is fine if it shows separate graphs for each of the two entrances. I was playing with it without much luck though if I start from scratch and you use the DAQ assistant, I'm able to get information without penalty. Any help would be appreciated.

  In fact you are 99.99% of the way.

  You just need to 4 characters

  

  The name filtering on this control is even properly defined to allow multiple selections and just shift click on the second channel

• Dynamic data of several channels in table, then save in Excel

  Hello

  I am acquiring data from several channels (4-5) and I'd like to collect samples at low rates (10 Hz for 3 minutes max). For various reasons I use Dynamic Data type, although I know that it is not the best way (some say it is a wrong data type ). I also want to save data to a file (the best option would be data excel file).

  If I acquire data 10 times per second, it is quite slow to save in excel (this is the slowest option of all types of data). So I would like to fill a table or matrix of acquired data and then write Excel file (I use scripture to measure file). But I don't know how to do - if I convert DDT in DBL, build an array and connect it to change registry, it works but I lose the information in column names and I'm wasting time. If I connect to build the table a DDT and then shift record another, it returns the table 1 d of DDT. I would like to have 2D DDT, which collects all the information loop.  Is there a suggestion how to solve?

  I'm sure it would be easier solved my problem with the double data type but I also use select signals VI which is the VI I am not able to replace at this time.

  Good day

  Lefebvre

  I don't know if there is a question here, or what.  Doing what you say you want to make, acquire the data of 4-5 channels at low rates (10 Hz for 3 minutes) and save the data in an Excel file (I assume you mean really Excel, i.e. a file with the extension .xls or .xlsx) is really a very easy thing to do in LabVIEW, especially if you are not using :

  • DAQ Assistant
  • Dynamic Data
  • Write to the action file.

  Indeed, you seem to realize this, but I guess you want to 'do the hard', in any case.

  Good luck.

  Bob Schor

• Error in the capture of several channels using pre-trigger

  I have problems of acquiring data with pre-trigger samples during the capture of several channels, using hardware NOR-PXI-6071E and Analog Input VIs in Labview (inheritance OR-DAQ).

  My goal is to trigger a signal, while capturing another. Unfortunately, I can't use the PFI0 for external triggering, as our cables/material have already been built, so I have to use an analog input as the trigger channel. I understand that to do this I must capture the two strings and the string I want to trigger outside must be the first string in the list.

  If I trigger and capture on the same channel (I tried 1-4) then it works very well, regardless of the number of samples before relaxation together. If I capture more than one channel (the channel of the relaxation to a first), with no pre-trigger samples, then trigger and capture both work very well. However, if I do the same thing with pre-trigger > 0 sample I get the following error:

  Error-10621 to AI control. Possible reasons:
  NOR-DAQ LV: The specified trigger signal cannot be assigned to the resource for the trigger.

  I don't have to such limitation explained in the user manual, and the forum search, I found a few other people who have had the same problem but they had no solutions. Any ideas?

  Hi Jackson,

  Unfortunately, this is a hardware limitation when you reference analog trigger via one of the lines to HAVE.

  Please see this knowledge base. Particularly the second paragraph says

  The error-10621 appears immediately when the VI running if you try to assign scans of relaxation before while scanning multiple channels and using one of the entries as your trigger channel.

  Details are explained in the third paragraph:

  Because all the entries are multiplexed before being sent for analog triggering circuit, it is possible that the trigger on the trigger channel conditions might miss while the device is multiplexing by another channel. In this case, the trigger will not be detected.

  It is explained in the E-Series user manual page 10-3.  Specifically the second paragraph of the section entitled "Analog Input Channel".

  Eric S.

• Find channels and cDAQ modules

  I have looked around the previous messages, but can't seem to find what I'm looking for.

  In most of my experience, I've implemented some DAQ and once the modules and channels are all in place, which is where they stay forever.

  Since I know things will not move, I create tasks in DAQmx.

  I'm working currently on a new installation program, but the problem is that in things cDAQ will not be in the same place every time.

  The application must read a number of strain gauges, which will be connected to the NI 9235 modules.

  It will take place anywhere from 1 to 3 modules attached, and they can be in one of the 8 available cDAQ chassis slots 9172.

  In addition, within a given module, anywhere from 1 to 8 channels will be connected.

  So basically, I guess my questions are running:

  (1) how many modules are connected and where?

  (2) in each module, the number of channels is turned on and how much is empty.

  From there on, I use DAQmx palette to take care of things.

  Thank you!

  So with every new start of the program, you will have a known device (your strain gauge device), but unknown channels. Here's how I attacked only a few years ago...

  • DAQmx create a task to create a job.
  
  
  • Make a constant table of all known possible channels. Say that it is 8 cells and compare that to an array of channels USED, making false tracks off the chains 'Unused' and the names of real channel out of used ones. Under certain conditions to check which ones which is used to remove the appropriate channel and add the DAQmx virtual channels properly. The VI snapshot below goes into the details. I brought not only the channels, channels, such as min/max properties and bridge information. My VI also made bridge removal, under certain conditions, depending on sensor that the user wanted to null (that part is not shown.)

  This code isn't super sleek, but I hope this gives you the ideas come from.

  

• Use several channels in the order of RT

  Following this post, and based on a simple sequence of RT that monitors a single channel, now I want to control multiple channels with setting specific time and level. The logic of this was to pass an array of strings that you want to monitor in the .vi create sequence parameter assignment (channel) and use arrays to manage all the time and level settings.

  

  However it seems that the sequence of RT cannot manage this type of object... so, how do I extend this functionality to several channels... Maybe that's the wrong avenue to use rt sequences?

  L.

  ... well, I look at one of the approaches is to create several calls sequence on a given sequence, each with different settings, then start them all in parallel. It seems to work for the moment.

  A simple question as opposed to events is used (for now) to detect when each called sequence stops and returns its result.

  Laurent

• sample per channel and read sample

  Hello everyone

  I'm new in LABVIEW and I have some difficulties with something.

  I put t know exactly what is the difference between the sample by channel and the sample to read. According to me, knowing that the sample by channel is the size of the buffer that is larger than the sampling frequency, but I put t know what is the sample to read.

  I ve tested with different sample per channel and read. Sometimes I get an error and sometimes know and I would like to know why. If you have examples because I understand better, it will be great.

  I really need to understand this part of my project

  Thanks for your help

  Tony GIBERT

  Hi Roro,

  As you mentioned, when the size of the buffer absorbing continuous samples, you can specify the sample by placing a value to the entry "samples per channel" on schedule vi. The entry of 'number of samples per channel' on reading vi which automatically names a control / constant with 'samples to read' specifies the number of samples you want to remove from the buffer in an appointment during playback of several samples (N). This link may provide a little more detail. I am also attaching a good example of the finder OR example that you may find useful to explore. I assume you are using the DAQmx driver put then please let me know if this isn't the case, but the same principles should apply in any event.

  This means accordingly for sampling at a given rate, you must make sure you're pulling data in large enough 'chunks' so that the buffer overflows (which may well be the cause of error that you see). On the other hand if your sampling rate is slow and your reading vi is having to wait the number of samples to read you have specified to be available, he can lift a time-out error. You can avoid this by increase your sampling rate, reduce your samples to play or increase the time-out specified read vi entry (-1 means it will wait indefinitely).

  Let me know if this helps and how you will.

  All the best.

• can I connect a bently nevada all sensor 3300XL 4-channel NI9234 DAQ

  Hello

  We bought a 3300XL Bently Nevada proximity sensor which comes with a Miniature of the ClickLoc coaxial connector with protective connector, standard cable. We have a 4 channels NI9234 DAQ.

  Please any suggestions on the type of adapter to use?

  Thank you.

  I'm not an engineer OR app, but as far as I know there is not NOR-DAQ with a V-24 and a - reange of 20V input supply.

  Maybe the other way around: what does measure?  Your sensor seems to have a fairly high nonlinearity... maybe get another sensor?

• asynchronous IO with PCIe-6535e and DAQ - mx

  Hi people:

  I am trying to explicitly define and use either async or sync I/O using a PCIe-6535e DIO with DAQ - mx card. Nowhere in the acquisition of data-mx vi can I find the adjustment means either async or sync I/O. Does anyone know of an explicit vi reference say examples that I missed when this is discussed and or fix.

  Also, assuming that I learn how to set the ack/write to the map mode, which defines the functionality and the strobe effect of the PFI pin which act as out of my data / data in banner? I can see that things like width pulse, delay etc. can be defined, but how to define? Or do I have to declare another channel with DAQ - mx and these control me manually. I tried, without real success.

  For example, it would be really useful to do.

  PFx pin _________-----------___________

  xxxxxxxxxxxx XXXXXX (0xe7) line0:7

  For the data from the card.

  and

  xxxxxxxxxxxxx xxxxxxxxxxxx (0xCA) line0:7

  PFx pin ___________-----_______________

  For the data of the car. In this case I'd be strobe the PFx in my FPGA.

  I'm a bit confused as DAQ - mx does not seem to give me the command that I need to set the e/s mode, and I can't find any explicit

  mention as to who, or how to properly synchronize the features of the PFI pin with my data from my vi.

  Thank you.

  Andrew

  Hi Josh:

  After discussions with our technical help academic rep, he suggested I oversample data and incorporate the pulse in the data. I did a little twist on the idea and I have attached a vi test I did. This creates just what I need. It'll work. I got def like other options, but it's good enough for now. If I had a devil FPGA I could move the world, and I can't do the code kludgy as that I joined. I would be interested in def in what other solutions that you or someone else could lead to the hearing.

  Thank you.

  Andrew

• Channels and parallelism

  DB version: 10.2.0.4
  
  All our items of rman backup are saved in an NFS mount. Our 1 TB database takes about 7 hours for a full backup. We want to increase the performance of RMAN.
  
  
  will show a SHOW ALL

  CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
  CONFIGURE CHANNEL 1 DEVICE TYPE DISK connect 'sys/mypass@thnprod'  FORMAT   '/u04/rmanbkp/thnprod_%U.rmbk';

  Question1 .
  The Oracle Documentation
  http://download.Oracle.com/docs/CD/B19306_01/backup.102/b14191/rcmconc1.htm#i1012864
  
  I think that a channel is actually a server on the target or auxiliary database session and a stream of data to the database for the type of backup device.
  We plan to enable parallelism.
  
  If I want to increase the degree of parallelism to 5, I need to set up 5 channels as well. Right?
  
  
  Question2 .
  
  For the prescription above can I set the configuration that

  CONFIGURE DEVICE TYPE DISK PARALLELISM 5 BACKUP TYPE TO BACKUPSET;
  CONFIGURE CHANNEL 1 DEVICE TYPE DISK connect 'sys/mypass@thnprod'  FORMAT   '/u04/rmanbkp/thnprod_%U.rmbk';
  CONFIGURE CHANNEL 2 DEVICE TYPE DISK connect 'sys/mypass@thnprod'  FORMAT   '/u04/rmanbkp/thnprod_%U.rmbk';
  CONFIGURE CHANNEL 3 DEVICE TYPE DISK connect 'sys/mypass@thnprod'  FORMAT   '/u04/rmanbkp/thnprod_%U.rmbk';
  CONFIGURE CHANNEL 4 DEVICE TYPE DISK connect 'sys/mypass@thnprod'  FORMAT   '/u04/rmanbkp/thnprod_%U.rmbk';
  CONFIGURE CHANNEL 5 DEVICE TYPE DISK connect 'sys/mypass@thnprod'  FORMAT   '/u04/rmanbkp/thnprod_%U.rmbk';

  ?

  10g RMAN automatically opens the number of channels required for your specified parallelism.

  That's why

  CONFIGURE DEVICE TYPE DISK PARALLELISM 4;
  

  should be enough. (I prefer the numbers 2, 4, 8 for parallelism).

  Given that your backups are on a NFS drive, you also suffer network transfer fees.
  Why not make compressed backups - that will reduce the size transferred over the network (even if it may take considerably longer if the processors are not good enough. Especially if you have several channels, migh reduce you the number of channels when the compression is activated).

  The command is

  BACKUP AS COMPRESSED BACKUPSET DATABASE ....
  

  Hemant K Collette