Mutiple global channels

In LV 7.1 how do I create a DAQmax task from multiple global max channels. The global channels are all analog but different types in a PXI\SCXI chassis

Hi Larry,
Please refer to the following link that discusses your issue:
http://digital.ni.com/public.nsf/websearch/3296BA2AEF586B7386256D6D00528E3D?OpenDocument
Regards,
Ankita A.
National Instruments

Similar Messages

  • How can I set the parameters of global channels and tasks previously created inside my applicatio​n?

    Hi everyone !
    Before proceeding to the description below I think it´s important to say that I´m using NI USB-6008 as DAQ device and the driver used is DAQmx 7.5.
    I´m currently developing an application into which I intend to be able to have complete control of the DAQ device being used, i.e, I´ll be able to create, delete and change the configuration of global channels and tasks previously created, among other things.
    To achieve the ends specified above I´ve already developed two vis, one to create global channels and the other to create tasks, and these two are doing a fine job. After this, I thought I came to the easy part ... I think I couldn´t be far for the truth! I thought that everything I should do was to specify which channel or task I´d like to configure and then use a property node to get the results I wanted, but it´s not working ...there are some DAQmx property nodes I thought I could use to do it  but I didn´t find a way to change the configuration of the global channels, and none of these property nodes seemed to work, i.e, although the simple vis used to test them ran the chosen parameters didn´t alter at all, after each execution I used MAX to see if they had changed, and to my chagrin they hadn´t.
    Can anybody lend me a hand with this problem? As always, any help would be deeply appreciated !    

    Hi Giovani,
    There is a developer zone tutorial that discussus some advanced data acquisition features including programmatic saves of NI-DAQmx tasks, global channels, and scales.  This tutorial also includes an example program.
    I wrote a short program that creates tasks in MAX. Whenever I wanted to change a part of the task, I would just change that feature in the example program. Take a look at the examples and please let me know if you have any further questions.
    Regards,
    Hal L.
    Attachments:
    create task example.vi ‏33 KB

  • Virtual Global channels created but not selectable

    I have recently updated all of my drivers to the latest version for Labview 7.1 in Windows XP.  As a result of this upgrade, I no longer have access to my virtual global channels, which all transferred and still exist.  Old vi's created with global channels continue to execute, and existing tasks, which reference virtual channels continue to work; however, I believe that this is a result of the NI drivers converting and storing these configurations as logical channels.  Anyway, when creating a new task from within MAX, or using the DAQmx express vi's from within Labview, I no longer have the tab that allows me to select which virtual channels to add to that task, eventhough all of the virtual channels are still defined correctly and available from within MAX.
    Any help would be appreciated.

    Hi Kike,
    After your harddisk crashed, did you reinstall everything?  Make sure that you installed LabVIEW first, then the DAQmx drivers and finally the hardware.  If you did not install in that order, then it's possible that issues might arise. 
    Are you saying that you have 10 Global Virtual Channels and 7 Tasks, but now you don't see them, or is the issue still when you try to create a new task you don't see the Global Virtual Channels avaliable? 
    As for the example finder, are you getting an error message like NI Service Locater is not Running or are you not able to find the NI Help Server?  You can click on the two links for some trouble shooting steps if that is the case.
    If my assumptions are not correct, please provide more information so that I can understand your situation.
    Message Edited by Nick F on 07-30-2007 07:11 PM
    Thank You,
    Nick F.
    Applications Engineer

  • Modification of Global channels In NIMax while Labview Program running, not updating in Labview

    Hello,
         Okay, here is my issue.  I have a program that reads data from a device using global channels in MAX.
    Step 1:  I open MAX with the systemExecute.vi with the parameters to wait till program finishes.
    Step 2:  I Modify a channel in Max, for example change the assigned daqMX Scale, or Min Max values.
    Step 3:  Save channel in Max.
    Step 4: Exit MAX with the file exit.
    Step 5: The Labview program continues, and I re-read the available global channels and global scales in the Labview vi but the properties have not changed to match what I change in MAX.
    If I stop the VI then start it again and read the global channels then the properties get updated.  How can I get the channel properties to update in Labview after changes are made in Max without stopping the labview vi and starting it again?

    Many properties of the channel can only be modified when the task is not running.  Have you tried stopping the task in LV before modifying the parameters, and then re-starting the task?
    Dan

  • Can Max global channels be programmatically added to a created task?

    I can add Physical channels to a created task, but cannot seem to add global channels to a task that was previously created.  The problem here is that I want to create my task with the channels (both physical and global) in a specified order.
    Thanks,
    Mike Sachs

    Hi Mike-
    You can add global virtual channels to a programmatically-created task by using the DAQmx Create Task VI.  This allows you to create a task with existing global virtual channels and then add virtual channels at run-time in the usual manner.  Here's an example that shows a global channel (created for Dev5/ai0) and a virtual channel within the same task:
    Hopefully this helps-
    Message Edited by Tom W [DE] on 02-09-2006 11:06 AM
    Tom W
    National Instruments
    Attachments:
    global_virtual_task.JPG ‏52 KB

  • Create global channels programmatically

    hello all,
    my question is related with daqmx.
    i want to know if theres any way to create global channels or tasks programmatically without using max or daqmx assistant
    the usual procedure is to create global  tasks or channels using max or daqmx assistant and then add them to ur tasks programmatically.
    i want to avoid the use of max here and create channels programmatically that can be used or called later.
    Solved!
    Go to Solution.

    You can use the DAQmx Save Task or DAQmx Save Global Channel VIs to save them programmatically.
    http://zone.ni.com/reference/en-XX/help/370469AA-01/lvdaqmx/mxsavetask/
    I agree with Dennis though, almost all DAQ tasks can be accomplished using the standard functions.  You might want to take a look at some DAQ examples by going to Help > Find Examples > Hardware Input and Output > DAQmx.  I always start with these examples and modify them as needed.
    Matt J
    Professional Googler and Kudo Addict
    National Instruments

  • Porperty "Descritpion" of a global channel

    Hello all,
    I have have to update a piece of software (written in LabVIEW 6.1) which read the description of a DAQ-Channels and dsiplays this information.
    It uses the traditional DAQ functions (the channel descriptions can be set through the M&A Explorer).
    After switching to LabVIEW 7.1 for the software and DAQmx for the hardware, I found, that the description of a channel could not be set through M&A.
    With the property "Description" of a global channel used in LabVIEW, I can assign a description to a global channel. But this description is only available as long as the software is alive.
    Two questions:
    1. Where can I assign a description to a global channel
    permanently (like to traditional DAQ channels)?
    2. Is this the right place for my question?
    Regards
    Heinrich

    Hi - you can programatically update and write to a global channel in DAQmx 7.4 and higher, however you cannot do this through MAX directly, so you have to make your own utility to do this.
    Have a look at http://www.ni.com/info
    and type in daqmxpro in the box.
    Hopefully that will give you enough information for the future.
    Thanks
    Sacha Emery
    National Instruments (UK)
    // it takes almost no time to rate an answer

  • Parse out global channels

    I have cDAQ 9172. The users will enter different global channels and I want to parse out the digital channels and have them in a seperate array. The other channels should be in the same order as the user selects. I am reading in global channels that will always be in the same format but never in the same order. Example: 9401-DI-1:2 .... and 9205-VI-1:3 and 9237-PI-1:2 would end up in two tasks. The Analog In tasks will be 9205-VI-1:3, 9237-PI-1:2 and I would then have a different task for the Digital Input 9401-DI-1:2. The user should be able to enter tasks in any order.
    Solved!
    Go to Solution.
    Attachments:
    ParseGlobalChannels.vi ‏15 KB

    Well I solved this myself. Didn't see the Match Regular Expression Function. That allows the use of the or function and makes things a whole lot earier.
    Attachments:
    ParseGlobalChannels.vi ‏21 KB

  • Change global channel programmatically????

    hi..
    is it possible to change a physical channel in global channel programmatically?????????
    i am using labview 8.2......

    Duplicate post (by browser's mistake ?!) .
    - Partha
    LabVIEW - Wires that catch bugs!

  • Labview can't see global channels

    This is the first time I have used DAQmx, so apologies if I'm doing something really stupid...
    I'm using a PCI-6221. I have configured a number of global virtual channels. However, when I try to access any of them in Labview, they are not there.
    If I use Get Channel Information.vi, it always returns error -10003. If I try AI Acquire Waveform.vi, running it as a stand-alone vi, when I click on the channel input selector and choose Browse, I see "Select Names", and an empty listbox.
    This is a brand new install of Labview 7.1. I'm using Nidaq 7, version 7.4, installed from CD this morning.
    Chris

    I shall quickly swoop in with a possible solution before you go buying more hardware...
    It's possible to simulate devices with NI-DAQmx. This will allow you to support your customer without having to buy another M Series. See, we aren't just after you're money
    To simulate a device, right click on NI DAQmx Devices >> Create New NI-DAQmx Device >> NI DAQmx Simulated device. Then choose the device you need from the list.
    You can interact with this the same way as you would with a real piece of hardware, you just won't be able to acquire any real signals. It will allow you to start programming without any hardware though.
    In NI's defense, the reason for moving from NI-DAQ to NI-DAQmx was purely a performance upgrade. The DAQmx API is much more user friendly and I'm sure you'll have no problems learning to program in it.
    Happy programming!
    Sarah
    Sarah
    Applications Engineer | National Instruments | UK & Ireland

  • Virtual Global Channels on 9234

    Hello,
    What are the AC/DC coupling and IEPE default settings when creating a Global Virtual Channel (Voltage) linked to a DSA (NI-9234)?  These options are disabled for the voltage type virtual channel.  
    I can't test it myself as I'm waiting for the hardware.
    Regards,
    Patrick
    Solved!
    Go to Solution.

    What frequency is your sine wave? The AC coupling filter characteristics are listed in the specifications (www.ni.com and search for 9234), and low-frequency tones will be progressively attenuated as the frequency approaches zero, DC.
    I do not think there is any way to change the defaults for a particular DAQmx device. I recommend setting the configuration explicitly for parameters that affect your measurement. In the future, you can use simulated devices to determine defaults and even begin application development while you wait for your DAQmx devices.
    Message Edited by dsb@NI on 05-11-2009 11:22 PM
    Doug
    NI Sound and Vibration

  • A task containing a single global NRSE ai channel thinks it's differenti​al!

    Help, surely this is a bug (either in my brain or in labVIEW!).
    I'm running DAQmx on a PCI-6229 m series DAQ device, SHC68-68-EPM cables and the CB-68LPR break out PCBs.
    I'm measuring ground referenced signal sources of a few volts in amplitude, some of which share a common ground and I am therefore using NRSE measurements on those to preserve free slots.
    I've set up a global channel called ILD1 as dev1/ai0 set as NRSE. The connection tab on MAX gives the connections I would expect:
    signal: pin 68 (ai0)
    ground: pin 62 (aisense)
    When I run the test panel for the global channel, I see exactly the measurement I expect so this works fine.
    I have then set up a task containing this global channel (and no others). The task seems at first to recognise this as being NRSE (having inherited this from the global ILD1 settings). However, if you look at the connections tab, the connections are now different:
    signal: pin 68 (ai0)
    ground: pin 34 (ai8)
    Running the test panel on this task gives a voltage that floats towards a maximum value. This is consistent with the fact that the task seems to think it's now doing a differential measurement, but I have not connected ai8 and so this input is floating.
    So the question is how can the global channel be NRSE (which I want), and a task based solely on this end up as differential? How can I fix this to preserve as many ai pins as possible (e.g ai8 would be useful for something else!)
    Thanks

    HI probably-
    probably wrote:
    I have ai0-ai7 set up as NRSE, as they share a common GND which I have connected to aisense.  I have four other signals to collect, which also share a common ground (but possibly different from GND). My thought was that to prevent any gnd offsets, I would measure these as differential mode. So I set them up on ai8-ai11 (I assumed that ai12-ai15 would be the other terminal on each of these signals). However, you can't do this: a mixture of differential and NRSE is not allowed on the same connector. Setting the four up on ai16-ai19 allowed me to measure them in differential mode. I presume this is because of the way the multiplexer works on the input amplifier?
    btw, I've found this forum tool pretty good, apart from accidentally pressing tab to get a space, then return by accident and submitting a partial post
    A mixture of NRSE and differential channels is certainly allowed on the same connector.  The problem arises in the placement of channels.  In differential mode the channels are connected on two seperate channel input pins; the positive pin goes to pin ai[X] and the negative pin goes to pin ai[X+8] where X is the channel number specified for differential input.  So, on a card (or a single connector on a two connector card) you can only create differential channels on the first 8 analog input channels.  Differential input channels on ai8-ai15 are not allowed because there isn't an [X+8] pin to access. 
    If you arrange your four differential channels somewhere in the first 8 inputs (i.e. ai0-ai7) and the NRSE channels anywhere else you will be able to acquire all signals in the same task on the same connector at the same time.
    EDIT:  I forgot to mention one caveat that might be obvious but is still worth mentioning- using a differential channel on a pair of inputs reserves the second pin.  So, if you create a differential channel on ai6 for instance, both ai6 and ai14 will be reserved.  This means that you will not be able to use ai14 for NRSE input.
    Hopefully this helps-
    Message Edited by Tom W. on 08-20-2005 06:52 PM
    Tom W
    National Instruments

  • Is There a way to programmatically extract global virtual channel info from max?

    I have a group of DAQmx virtual global channels setup in MAX and I would like to be able to programmatically extract the physical channel information to be included with the data file. In the past I have been able to use traditional NI-DAQ channel utility vi's to accomplish this, but they only see traditional NI-DAQ virtual channels and not DAQmx virtual channels. Is there a group of vi's for extracting DAQmx virtual channel information? I'm using Labview 7.1 with a Windows XP OS.

    Paul,
    I can access basic properties using the approach you described, but do you know how to get the units from the global virtual channel?  Say I had a general appliance for reading in load cells, and I wanted to have the axis labels in a graph show the units of whatever load cell had been selected.

  • How can I select a channel on the RT target with a VI on the host?

    Maybe I'm trying to pound a square peg into a round hole, so please let me know if I'm abusing LV, but ...
    I'm trying to parameterize our RT VI app that deals with digital output channels.  We use the same basic VI for multiple configurations.  The only thing that changes is the channel allocations.  So for instance, actuator 1 is on port0/line5 for one configuration and port1/line2 in another.  I really don't like the idea of modifying the VI every time we have a new configuration because it makes configuration management insane.  If I make a change to the basic VI, now I have to upate N copies of the VI and hope I catch everything.
    So I'm making the main app VI read an XML configuration file that specifies all the allocations.  Sounds great at first, but how do I create the XML file?  I created a VI that manages the data in the VI, allowing the user to add/remove channels and edit the name and channel and then save it to an XML file.  The configuration is comopsed of an array of clusters, with the cluster containing the name and DAQmx channel.  My intent was to let the user select the channel from the list of valid channels by using the DAQmx Global Channel control.  But the problem is, the configure VI runs on the host, which doesn't see any of the channels because they are on the RT target.  But if I try to run the configure VI on the target, it refuses to deploy because I have GUI widgets.
    Is my approach fundamentally flawed?  Is there a better way of parameterizing our VI?  Or is there a trick to getting access to the valid channels on the host VI?  The information MUST be available because after all, when I modify a target VI and select a global channel constant, I'm doing this on the host.
    Thanks,
    Keith.

    Hi Keith,
    you can handle the channels like "normal" strings. See the attached picture.
    Hope it helps.
    Mike
    Message Edited by MikeS81 on 07-25-2008 06:46 AM
    Attachments:
    Unbenannt1.PNG ‏6 KB

  • NI-DAQmx false duplicate channel error

    I have an SCXI chassis w/ a SCXI-1600 and a SCXI-1102 w/ SCXI-1303
    accessory.  I created a series of NI-DAQmx global channels for
    thermocouples, calling them Air Temp0 through 17.  Using NI-DAQmx
    subvi's I read them.  See a very simplified VI attachment. 
    The channels individually all check out, but when I try to read the
    entire group, I get an error -200072 and it says that Air Temp15 and 16
    reference the same physical channel, but when I check the channels in
    MAX, they are indeed different.  Likewise, if you read one at a
    time and stimulate the various thermocouples, the displayed response is
    always consistent with the physical channel. I.E., if you heat the
    right thermocouple, the reading goes up, but if you heat the wrong
    thermocouple, the reading doesn't go up. 
    Using the simple error handler, the error message is:
    "Error -200072 occurred at DAQmx Read (Analog 1D Wfm NChan 1Samp).vi
    Possible reason(s):
    Duplicate channels in the list of physical channels are not supported by this device.
    Channel Name: Air Temp15
    Duplicate Channel: Air Temp16
    Device: SC2Mod2_Mini
    Task Name: Air Temp15:16"
    Any ideas?
    Attachments:
    diagnosis.vi ‏59 KB

    Thank you for your input. It does seem to have been a corruption of the configuration somehow. 
    This is one of the things I hate about MAX.  The unexplained and
    unexplainable corruptions.  And then the usual solution: 
    "Oh, reinstall everything and try again."  Grr.  This has
    been going on for years now.
    The station had not crashed or otherwise displayed any
    misbehavior.  The channels were configured by doing the first one
    and then duplicating it using the MAX "Duplicate" feature.  I then
    made a set of channels by individually programming each one, with a
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    renamed the new ones to the desired names.  Whaddya know, they
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    'way too many other things on my plate to be spending 6 hours chasing
    corruptions like this.  Virtual Instrumentation is supposed to
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