Multiple channel waveform output using a 6711 board
Hi,
I am writing a driver for VxWorks RTOS based on the DDK for a NI6711
analog output board. I cannot find an example for timed waveform
output on more than one channel. I adopted aoex3.cpp (which works
fine under VxWorks for one channel) to operate also multiple channels.
I set all DACs to timed and wrote to the waveform generation register
once for each channel. I tried several settings for the number
of channels:
theSTC->AO_Mode_1.writeAO_Multiple_Channels(1);
theSTC->AO_Output_Control.writeAO_Number_Of_Channels(iNumChans);
None of the settings of iNumChans results in the correct output on all selected channels.
The comedi driver uses the settings
theSTC->AO_Mode_1.writeAO_Multiple_Channels(0);
theSTC->AO_Output_Control.writeAO_Number_Of_Channels(0); But that does not work either
Any help would be very much appreciated.
Heike
Attachments:
aoex7.cpp 20 KB
Soory , here is the attached example
Attachments:
aoex7.cpp 20 KB
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Multiple inputs and outputs using DAQmx VIs
Hello,
I am fairly new with the LabView programming language. I have a few training books that I have been reading, and I have been following online tutorials and reading the forums. However, I have come to a problem where I don’t see a clear solution. I am using LabView 2009 (9.0f3) and DAQmx VIs.
I am using a NI 9172 chassis PLC, with two 9201 AI cards, 9217 AI RTD card, 9472 DO card, 9263 AO card, and two 9237 AI Bridge cards.
I am reading eight analog inputs with the 9201 cards, two analog RTD inputs with the 9217 card, three digital outputs with the 9472 card, three analog outputs with the 9263, and eight analog inputs with the 9237 cards.
I wrote a simple program to test one digital output task, two of the analog output tasks, and a single analog input task. I put all of them in the same while loop, and it worked perfectly. However, when I add analog input tasks to the same loop, I get an error 200022. So I tested each sensor individually by changing the channel before each run. I searched error 200022 and found that this is because I cannot start another analog input task until the previous one ends. With this said, I don’t know how to acquire an analog voltage in the same task as an analog RTD voltage. Both inputs take different constants in the start task DAQmx icon.
Attached is my test program. It is titled “Test All”. This is the program I used to test the various sensors. I tested the input sensors one at a time, and it worked fine. A few tasks are written just to test functionality, and will be added to later. The data is only displayed on the screen. I will add triggers and data write to disk functions later. This program works now, but if I add more analog inputs, it will generate the 200022 error.
Can someone show me how to correctly write the code for multiple inputs and outputs using DAQmx? All training materials and tutorials I can find all show a single input or single output, not multiples of each. Thanks for looking.
-Randy
Attachments:
TestAll-NI.vi 32 KBHi RandyC,
The Knowledge Base article Using Different Types of DAQmx Global Channels in the Same Task goes into a little more depth of what Bryan is talking about, and it also includes some example code to help show what to do.
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Need advice on best way to acquire multiple vibration waveforms from a PXI-4472 board
I'm using a PXI-4472 board to acquire vibration data from 8 proximity probes, each with different scaling. Confused as to best approach to achieve this given all the options with MAX, LabView and its Sound & Vibration toolset scaling. Reading other posts, it appears that 24 bit acquisition also requires some special treatment.
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Hi,
I am using NI LabVIEW, NI PXI 4071, and NI PXI 6070E to measure current through a variable resistance. Now, I am using one channel from SCB-68, but I want to add another channel in parallel so that I can have two resistors instead of one that I cam measure current through them.
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Thanks in advance.
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Attachments:
IV copy for HS.vi 55 KB
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Continuous aquisitionof multiple channels to output file
i am using the DAQ PCI 6254 along with the SCB-68. i am trying to sample 9 different voltages. i want to be able to start the acqisition and then have it run until i stop it a few minutes later with a button or switch because i dont know how long i will need to aquire. after it is stopped, i want to be able to save this to a .txt file. i have tried using different loops but i can not get all the data into the file. i am new to labveiw so i sure there is a simple way to do this. any help would be great. thanks
When are you sampling do you want to save the values in a tabulated form?
How do want to save it?
If your measuraments are real numbers you could use the VI Format into file along with the VI open file and closed file with a for or while loop to save in a tabulated form.
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This is the first time I've used LabView. I want to create a VI to be able to read viltages from multiple channels and output the value of each channel to individual numeric indicators in the VI. I know how to read a single channel and I've created a task in DAQmax with multiple channels but how would I put that into a VI that will do what I need.
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Message Edited by Dennis Knutson on 04-30-2007 09:49 PM
Attachments:
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Acquiring Analog Input from Multiple Channels in Labview
Hello,
i am working on a VI where i need to acquire signals from multiple channels in Labview using NI-9129.Initially i want to acquire contineous input signals (voltage and current) and display it on the graph.
Having looked at forum and Labview examples i tried to make an initail VI but i am not sure if the setup i made needs any modification to serve my purpose.I am fairly new to Labview software.
All i want is
1.To acquire conteneously current and voltage
2.Display current and voltage individually on the graph.
3.Perform some basic calculations like MAXIMUM,MINIMUM and AVERAGE values of voltage and current.
4.Log the data into excel file
I have attached the VI i made so far.i need abit of advice if i am moving in the right direction or not.
Thank You for having a look at my question.
Attachments:
Voltage-Current VI.vi 81 KBEngr_tech wrote:
i think i already have the tdms for data logging.as far as the tdms data logging is concerned,when i enable the logging mode to "read and log" the data logged inside the excel sheet would be seperate for current and voltage.?
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Yes, you are logging directly to a TDMS file. This is definately the best route for data logging from a DAQ. The currents and voltages will show up as different channels in the same group.
To add more channels, just add them to your DAQmx task. The logging will handle it with no issue. Your calculations will also a little work to add the extra channels. Same for the graphs, since you are using seperate charts.
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6733 multiple frequency waveforms
I am working with the PCI-6733 DAQ card in the DIAQMX C environment (Not Labview).
I need the card to perform two separate (but not simultaneously on the same card) functions
I need to be able to generate 8 sine waves of independently varying frequencies (from 50 to 70 Hz).
I need to be able to generate 8 square wave of independently varying frquencies (from 1 to 10KHz).
Any examples out there?
Thanks,
A HancockA. Hancock,
There is a handy example that illustrates waveform output using the onboard clock located in the DAQmx example folder. Assuming you installing DAQmx to it's default location, it would be located:
C:\Program Files\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Analog Out\Generate Voltage\Cont Gen Volt Wfm-Int Clk
Simply load a regular waveform into this example. It defaults to a sin wave, you could easily adapt it for a square wave.
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"C:\Program Files\National Instruments\NI-DAQ\Docs\cdaqmx.chm"
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Good luck,
--Paul
Applications Engineering
National Instruments, Inc
http://www.ni.com/support
--Paul Mandeltort
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Help! data manipulation for high speed streaming to disk from multiple boards and multiple channels
I am using Labview 7.1 and have been trying to capture data from 12 channels simutaneously sampled at 2MS/s each and streaming to disk for up to a minute or more. The hardware I am using is 2 x PXI 6133 S series boards with a MXI4 link to a Pentium D 2.8 Ghz machine with 2Gb ram. I have 2 sata drives set up in a raid 0 configuration which should give me hard disk write speed faster or equal to the MXI-4 transfer speed.
I have first started off by using the example code "multi device sync - analog input- cont acquisition" which has enabled me to sync the two boards and sample at the required speed.
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Is there a cleaner way of streaming this data to disk and keeping the channel data separated from each other?, and/or is there a better way to capture and handle the data I need?
I have attached the vi which I have got to consistantly work streaming to disk using the raw 1D I16 format.
Thanks in advance to anyone who can help.
Attachments:
multidevicesync_analoginput_streamtodisk.vi 197 KBHi,
i can suggest following
Refer to an example VI called as "High speed data logger.VI" in conjunction with "High Speed data logger reader.vi" in Labview examples. Alhrough the logger might be in Tradiditional Daq format, it can be quite easily converted to Daq Mx format to store data in Binary (I32 format) . I have used this for many of my applications and i have found that the data retrieved does not have any "messups".
Why not keep a seperate file for each card? This way, you do not have to load your application with extra process. You only have to acquire and save. After saving in Binbary format, you can retrive it offline, convert it to ascii format and merge the data files of various cards to get one consolidated ascii data file.
hope this helps
Regards
Dev -
Subject : it seems impossible to run a multiple boards analogical acquisition task with one or several analogical generation task using the same boards.
NI Configuration : Dev1 = Dev2 = 6321 boards
Development environnement : LabWindows CVI 10
Source code for analogical acquisitino task :
DAQmxCreateTask("",&AIRecordingtaskHandle);
DAQmxCreateAIVoltageChan(AIRecordingtaskHandle,chan,"",DAQmx_Val_NRSE,min,max,DAQmx_Val_Volts,NULL);
DAQmxCfgSampClkTiming (AIRecordingtaskHandle, "", rate, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, sampsPerChan);
DAQmxGetTaskAttribute(AIRecordingtaskHandle,DAQmx_Task_NumChans,&gNumChannels);
Chan = "Dev1/ai0, Dev1/ai1, Dev1/ai2, Dev2/ai1"
Source code for analogical generation taskS :
DAQmxErrChk (DAQmxCreateTask("",&AOtaskHandle_C1_DAC0));
DAQmxErrChk (DAQmxCreateAOVoltageChan (AOtaskHandle_C1_DAC0, chan, "", min, max,DAQmx_Val_Volts, "")); // chan vaut Dev1/ao0
DAQmxErrChk (DAQmxCreateTask("",&AOtaskHandle_C1_DAC1));
DAQmxErrChk (DAQmxCreateAOVoltageChan (AOtaskHandle_C1_DAC1, chan, "", min, max,DAQmx_Val_Volts, "")); // chan vaut Dev1/ao1
DAQmxErrChk (DAQmxCreateTask("",&AOtaskHandle_C2_DAC0));
DAQmxErrChk (DAQmxCreateAOVoltageChan (AOtaskHandle_C2_DAC0, chan, "", min, max,DAQmx_Val_Volts, "")); // chan vaut Dev2/ao0
At the first DAQmxReadBinary call attempt, the system shows an error (see attached document)
What we understand about that error : it is impossible to run the two set of tasks (ai and ao) using ressources from both Dev1 and Dev2 in the set of tasks because it is not allowed to use the same Reference Clock for that.
The question is : is there a way to to that without having that kind of message?
We tried different combinations :
- Using only one ao task (on Dev1/Dac0) : same error
- Not using any ao task (only the ai task) : no error
- configuring the ai task with only channel from Dev1 : no error
- Using "/Dev1/ai/SampleClock" as internal clock for the ai task and "/Devk/ao/SampleClock" for each ao task (k standing for "1" or "2" depending of the ao task we consider) : error
Thanks a lot.
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When I connect an input to DI channel of USB 6501 card from my board which has sourcing Output t, iIn the Off state it is not pulled down properly. The volatge on the port in is 2.1V -2.5V based on the pull down resistor on my board. I suspect that it acts as a voltage divider.
The state on the card is still show as "HIGH "state, even my sourcing output driver has a pull down resister. when I use this interface board for PCI mseries devices it works fine. Do the pull down resister on my sourcing output is not worth. Is this because of pull up resister 4.7k inside USB card 6501.
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Some boards with DIO have a pull up, while others have pull down. You just have to watch the specs.
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How to filter Multiple channels without losing outputs
Hello all, this really is my last hope. I'm having a real big issue in Logic, it's been that way since I started and I'm hoping someone help me. The issue is the same with every track I create, and is as follows:
An example I will use is the main 'drop' of a track. I want to have most elements gradually filtering out, to allow an emphasis when the beat kicks back in at the drop. At the same time, I want to leave some elements playing, such as reverse cymbal, rise/swoosh/sweep sounds etc. The problem I have is how to select multiple items to filter out, using ONE filter (eg. Beats & bass) and not have to put a filter on EVERY individual track and automate them individually.
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Displaying real-time data using gui meter from multiple channels.
I am using DAQ USB-6009 for my assignment. Part of my task is to display real-data from multiple channels in the form of gui meters. eg. irradiance and voltage...
I used a split signal to separate the signals from different channels coming out of the data output terminal of the DAQ assistant. The problem is that I do not know which vi to connect in between the split signal and the gui meter. I am looking for one vi that is capable of handling signals (measurement) and outputting the data to the gui meters simultaneously and individually based on the channel they are coming from.Thnx for your tip, Dennis.
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DAQ-------> write to measurement file
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