Several channels of voltage measurement

Similar Questions

• 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

• 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

• Several channels AND DAQ

  Hello!

  I have a problem regarding the acquisition of data from multiple channels. I get a channel data in time, but when I try to do a similar code to get data from another channel, it will not work. This can be done with the DAQ assistant, but I want to avoid this solution, because it slows down the program a little.

  The snapshot accessory show how this is done for 1 channel. Can I use a similar program for the acquisition of several channels?

  Thanks for your help.

  You must only specify several channels in your task - i.e. Dev1\ai0:1 and replace the DAQmx Read N channels. Go to the task in MAX and click the channels button Add. Follow the directions.

• 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

• 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

• holds several channels of power control

  Given

  • Sector triple channel Keithley 2230-30-1
  • drivers needed

  I installed the instrument Drivers and can control the unit using the example VI provided by Keithley pictured below.

  

  Unfortunately, I can control only one channel at a time. Say that I set voltage channel 1 to 15V. When I switch on channel 2, the VI defines channel 2 voltage of 15V as well. If I change the tension of the chain 2 to desired tension, say 7V and then switch back to channel 1, then the VI defines the channel 1 voltage to 7V too. So I decided to make my own simple control VI on the picture below.

  

  Problem

  My sorta VI won't work.

  • When I run continually, I get the error below I know is because I'm not "final" background nets that control channel 1.
  • When I run with the executions of climax, my works VI, although slowly.

  Questions

  1. What gives? Why the VI does not work in debug mode but not normal?
  2. Can I combine the names of resources VISA? In my view, that such a feature would allow me to 'close' wire VISA of the thread from the bottom as error to conclude a package.
  3. Better yet, what is the right way of wiring of what I'm doing?
     I feel that my program does not work because I'm asking the PSU for read/write at the same time. Would be to place command of channel 1 and channel 2 control in structures of the sequence with 0 programmed delay me to "simultaneously" enable and control 2 channels independently?

  Thank you very much!

  The instrument and the physical interface does not support the parallel operation. Highlight run, you slow down things enough that they run in order. Never, never use the execution continues unless special debugging purposes. It is the main causes of your problem. If you want independent control, your VI could have a structure of the event that would change each channel when you click a button that you would have for each channel. Label then something like the Ch, Ch 2 Update 1 update, etc. This would have the advantage of writing only once for each channel on a change instead of constantly pounding the instrument with controls as you do now. For operation without user intervention, wire you functions in the order. No need at all a stupid sequence structure. The error links and name resource provides all the data flow.

• 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.

• 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.

• several channels switch scanning DMM

  Hello

  I use DMM (PXI of NI 4071) and switch (NI TB 2627). I want to make the measurement by scanning of a channel, then start to measure, after that, go to another channel and start measuring again (the so-called syncronous).

  But I have problem in my code to display the output of each channel. I can just show the output of channel 0 only.

  Here, I am attaching my code. Instead of display the output of the channels, in fact it can only show the output of channel 0 according to how many samples that I want. Which is why I'm trying so hard to show output from the other channels.

  can anyone help?

  Thanks for your help. =)

  Sorry, my code is very messy.

  Try changing your code as shown in the attached file.

• How to read voltage on several channels using the 6255\SCB-68

  Hi all

  I have been able to get the following code to compile, run and display the data as expected. When you read the tension (CSR) on Dev0/ai65

  ... Instruments\NI-national DAQ\Examples\DAQmx ANSI C\Analog In\Measure Voltage\Cont Acq - Int Clk\ContAcq - IntClk.c

  * I think I'm using CSR, but I have no idea since I don't see an argument to specify

  I'm reading two different data points:

  1 discovered (CSR) tension on Dev0/ai65

  2 show the (differential) voltage difference between Dev0/ai17 and Dev0/ai25

  Can someone point me to an example (or a web link) where two different data points are read.

  * edit - I am filling this task using C++

  Thank you

  Chad

  This code is a start, and it works

  
  
  using namespace std;
  
  
  
  
  
  
  
  
  
  using namespace std;
  
  #define DAQmxErrChk (functionCall) if (DAQmxFailed (error = (functionCall))) goto error; on the other
  int main (void)
  
  {
  <>
  
  	< "\t="" starting="" the="" ni="" daqmx="" data="">
  
  	<>
  int loop;
  < 3;="">
  
  	{
  
  		Int32       = 0 error;
  
  		TaskHandle  taskHandle1 = 0;
  
  		TaskHandle  taskHandle2 = 0;
  
  		Int32       read1.
  
  		Int32       Read 2;
  
  		float64     data1 [1000];
  
  		float64     data2 [1000];
  
  		tank        errBuff [2048] = {'\0'};
  Channel settings and the schedule of the analog voltage DAQmx
  
  		DAQmxErrChk (DAQmxCreateTask ("task1", & taskHandle1));
  
  		DAQmxErrChk (DAQmxCreateAIVoltageChan (taskHandle1, "ai25/Dev1", "", DAQmx_Val_Cfg_Default,-10,0, 10.0, DAQmx_Val_Volts, NULL));
  
  		DAQmxErrChk (DAQmxCfgSampClkTiming (taskHandle1, "", 10000.0, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, 1000));
  DAQmxErrChk (DAQmxCreateTask ("task2", & taskHandle2));
  
  		DAQmxErrChk (DAQmxCreateAIVoltageChan (taskHandle2, "Dev1/ai17", "", DAQmx_Val_Cfg_Default,-10,0, 10.0, DAQmx_Val_Volts, NULL));
  
  		DAQmxErrChk (DAQmxCfgSampClkTiming (taskHandle2, "", 10000.0, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, 1000));
  Starting code DAQmx
  
  		DAQmxErrChk (DAQmxStartTask (taskHandle1));
  Reading DAQmx code
  
  		DAQmxErrChk (DAQmxReadAnalogF64 (taskHandle1, 1000, 10.0, DAQmx_Val_GroupByChannel, data1, 1000, & read1, NULL));
  
  		< read1;="">
  
  			< data1[i]="">< "="">
  
  		<>
  DAQmxStopTask (taskHandle1);
  
  		DAQmxClearTask (taskHandle1);
  Starting code DAQmx
  
  		DAQmxErrChk (DAQmxStartTask (taskHandle2));
  Reading DAQmx code
  
  		DAQmxErrChk (DAQmxReadAnalogF64 (taskHandle2, 1000, 10.0, DAQmx_Val_GroupByChannel, data2, 1000, & read2, NULL));
  
  		< read2;="">
  
  			< data2[i]="">< "="">
  
  		<>
  
  		DAQmxStopTask (taskHandle2);
  
  		DAQmxClearTask (taskHandle2);
  Stop and clear spots
  
  	Error:
  
  		If (DAQmxFailed (error))
  
  			DAQmxGetExtendedErrorInfo (errBuff, 2048);
  
  		If (taskHandle1! = 0)  {}
  
  			DAQmxStopTask (taskHandle1);
  
  			DAQmxStopTask (taskHandle2);
  
  			DAQmxClearTask (taskHandle1);
  
  			DAQmxClearTask (taskHandle2);
  
  		}
  If (DAQmxFailed (error))
  
  			printf ("DAQmx error: %s\n", errBuff);
  }
  
  	end of loop
  <>
  
  	< "\t="" stopping="" the="" ni="" daqmx="" data="">
  
  	<>
  return 0;
  }

• I can not get the voltage measured by the voltmeter.

  Hello

  When I use the VI "Cont Acq & voltage graph - write data to the file (PDM) .vi" to view the NI PCI6251 voltage, the voltage is of approximately - 5V. However, the voltage I measured by the voltmeter of the channels on PCI 6251 is about 0. 3. also, when I use another VI to show the voltage, it is of approximately - 5V too. I don't know what the problem is. Thank you very much.

  
  

• How can I autoindex looping for to create several channels daqmx

  I'm trying to autoindex create a loop FOR containing the DAQmx vi to create AI multi-channel voltage with identical settings, except that I need to apply specific channel names using a constant and specific physical channels using a constant of channel. Wiring of a constant DAQmx of physical channel does not work because the data type is incorrect. Similarly, I don't understand how to use a string constant to autoindex through the channel names is or how to configure the constant string (s) to assign names. Also, when I try to make one of these, I get a tunnel to exit the DAQmx autoindex create channel, rather than a task out. I can achieve my goal using several explicit DAQmx create calls to channel, but for high channel count, it is very time consuming.

  I use LV 8.5.

  I'm hoping to find the code showing how to perform the conversion type, flattening, or what to do.

  Diane has.

  I have an array of clusters.  Each element of this array is a cluster.  The cluster consists of a (scalar) string and input/output (also scalar).

  In addition, my TI attachment extracted.  I think that your file has been LV2009.  If so, you can drag the image from the browser and drop it onto a diagram.

• Several channels daq

  Hello.. I use usb 6353 DAQ board for my project. I want to buy 3 different voltages and post it on labview. When I take a channel (ai0) data in the daq assistant it works fine, but when I add channels (ai1, ai2) in the nd task run it, tensions mix. I used split Subvi to separate dynamic data, but the readings are all wrong.
  What I am doing wrong?

  If you see ghosts?