-200428 - Modifying a channel in a predefined DAQmx task

I was pretty sure I had done this before, but maybe not. I have a predefined task setup in MAX spanning 3 different analog input modules on a cDAQ chasssis.
I'm attempting to modify the thermocouple type on one of the TC channels based on configuration setup data. So I have the task selected as a constant and feed it into a DAQmx Task node to get the Channel List. I can see the channel list just fine and all the channels are present there, but when I attempt to break the thermocouple channel out of the array and feed it into a DAQmx Channel node, I get an Error -200428, that the value must refer to a valid task or valid virtual channels.
Any clues?
Solved!
Go to Solution.

Hey Mike,
Can you please try it like illustrated in the attached jpg.
Christian
Attachments:
hint.jpg ‏36 KB

Similar Messages

Feature Request: Modify Audio Channels from the Timeline in Premiere CC.1

Why have we never been able to modify audio channels once a clip is added to a sequence? I'm guessing there's a good reason Adobe has never had this feature. The lack of this feature is explicitly mentioned a few times in the audio section of the Premiere Pro CC manual, as if it's a benefit NOT to have it. But the benefit is entirely lost on me.
In my workflow, I synchronize my double-system video and audio before anything else. I do this in PluralEyes (and unfortunately I'll have to keep doing it this way, until PPr's sync on sound feature gets fixed—for me it's never worked).
Once PluralEyes has synched hours of footage and audio and placed it on a PLURALEYES GENERATED sequence, I import that sequence into Premiere. Note: Since I haven't gone through the step of creating a blank New Sequence, I don't get the opportunity to setup my audio channels the way I'd like in my sequence (i.e. Stereo recordings should occupy ONE track, not two. Typically these tracks come from a camcorder and are used for reference sound, or ambient noise at best, so I don't need them taking up precious real estate in my sequence).
Since PluralEyes doesn't merge my clips for me (or rather I don't want it to since I'm usually doing multi-cam sequences where I want to keep all 14, or so, tracks of audio), I have to go through the clips one by one and do a Merge Clip action once I've adjusted any minor sync issues, or determined which tracks I actually want to keep. But, and here's the key, at this stage I'm not yet 100% certain whether I'll use the nat sound or the wireless mic sound (separate audio recorder, etc). Furthermore, I don't really want to think about that at this point. After I've spent a few mind-numbing hours just ingesting files, sync and merges, I want to jump into the edit as soon as possible, before I lose all will to finish this edit. If I modify my audio channels right now, I'll lose the ability to make some creative decisions later on.
I'd like to start whacking out an assembly edit. And then after I have a rough program, I can start looking at which audio tracks (nat or double-system) I like better in each circumstance. This is where I become stumped that at this stage, I'm locked into whatever audio channels I've setup (or not) in the earliest stage of the edit, back before any media was actually on the timeline! It's at this stage, and usually only at this stage that I want to start Modifying Channels—FROM THE TIMELINE!
Does anyone else feel the same? If not, what is your workflow?
Feature Summary: Right-click on any clip, (master clip, sub-clip, merged, nested or otherwise) in the timeline and choose Modify > Audio Channels.
I've submitted a feature request, with a link back to this discussion, so please pipe in—especially if you want this feature.

Maybe its your specific workflow, asset mangement and use of a 3rd party application that runs you into an issue.
Take Pluraleyes out of the equation, I would imagine my workflow is the same as most everyone else. Find footage in the Media Browser. Import it. Create a Sequence and start editing. Use the Source Monitor to set Ins and Outs and then Insert the clip on the timeline.
At this point, if the audio needs to be modified, it cannot be done on the Timeline. The workaround, of course, is to Find Clip in Project; Modify Audio in the Project panel; then do a Matchframe to replace the audio clip. This works, but requires many steps per clip. Also, Matchframe in Premiere Pro CC is not reliable.
Introducing a new Modify Audio (from Timeline) feature as seen in the fantasy screenshot above would solve it.
I dont use Pluraleyse ...which I understand to be a synching aid...so I dont know the workflow it imposes on one .
Returning to Pluraleyes workflow, this issue is compounded by the need to Modify almost ALL audio. Every stereo track is separated and placed on two MONO tracks taking up precious real estate. This is not something Pluraleyes imposes. It is due to the way Premiere imports XML timelines. This would apply to sequences imported from Final Cut as well.
In this case it would be ideal to select both the LEFT and RIGHT mono tracks and choose "Modify > Audio Channels > Merge L/R Mono to a Single Stereo track." Ideal? No. I guess Ideal would be if Premiere would interpret XML files properly in the first place.
What actually is the issue with Premieres synch and merge workflow in your case?
Audio Sync in Premiere Pro doesn't work. Period.

How to make a virtual channel in MAX using DAQmx ?

I want to measure the CJC temperature on the TBX 1328 ( attached to SCXI 1121). I want to create a virtual channel in MAX using DAQmx. I have right clicked on DAQmx but there is no option for virtual channel. Ther is the option of 'Traditional virtual channel' which i dont want.
I used the VI to make the virtual channel but i want to knowhow to doit inMAX.
thanks

Here are 2 ways that you can create a DAQmx channel that appears in MAX.
1) In MAX, right click on "Data Neighborhood" and select "Create New...". Then click "NI-DAQmx Global Channel" (or "NI-DAQmx Task" -- a task contains the channel(s) and triggering/timing information) and click "Next". This launches the DAQ Assistant that will guide you in creating the channel or task.
2) In LV, place a NI-DAQmx Global Channel control on your panel or constant on your diagram. Right click on the control/constant and select "New Channel(DAQ Assistant)..." (Note: You can do the same from the NI-DAQmx Task control/constant to create a NI-DAQmx Task.)
Deborah

Why can I not use the channel name, which is obtained from the function of DAQmx Task, as the input of the channel name for the function of Get Channel Information of DAQ?

Why can I not use the channel name, which is obtained from the function of DAQmx Task, as the input of the channel name for the function of Get Channel Information of DAQ?

Not a lot of details here, but my guess is this isn't working for you because you are wiring in the task to the Active Channels Property and not the actual Channel Name. I have attatched a screenshot of what I believe you are trying to do. The Task has 2 channels in it, so I need to index off one of the channels and wire it into the active channels input of the Channel Property node. Then I can read information about that channel
Attachments:
channel_name.JPG ‏69 KB

[svn:fx-trunk] 10151: Modified the Channel.applySettings() ASDoc comment.

Revision: 10151
Author:   [email protected]
Date:     2009-09-11 06:20:44 -0700 (Fri, 11 Sep 2009)
Log Message:
Modified the Channel.applySettings() ASDoc comment. Removed the XML snippet for the method parameter, which wasn't relevant to the primary way this method is used. This method is primarily used in our channel subclasses to add settings specific to those channels and then call super to get the base channel settings. If a developer creates a custom channel class, the developer could use it in the same way, but would be setting the applySettings() method on the custom channel class with properties specific to the custom channel implementation. This change addresses bug BLZ-294.
Ticket Links:
    http://bugs.adobe.com/jira/browse/BLZ-294
Modified Paths:
    flex/sdk/trunk/frameworks/projects/rpc/src/mx/messaging/Channel.as

Merged clips and modified audio channels bug/issue

My problem is that if I create a merged clip and modify it's audio channels Premiere (both CC and CC2014) does not respect the modification under specific circumstances. These circumstances are: if I use keyboard shortcuts or the source window buttons for overwrite/insert to cut the merged clip into a timeline. However, if I drag & drop the clip from the source window or from a bin into the timeline Premiere will respect the audio channels set through modify audio channels.
Here are steps needed to create my problem. You will need a video clip and an audio clip with at least two channels to reproduce this.
1. Create a merged clip from the video and audio. Does not matter if you have "Remove audio from AV clip" enabled or not.
2. Right click on the merged clip in the bin and select Modify -> Audio Channels.
3. Set the merged clip's audio channels to Number of Audio Tracks: 1, Channel Format: Mono. Set the source channel for Audio 1 to anything except Channel 1. Click OK.
4. Make sure you have the merged clip open in the source monitor. Use keyboard shortcuts (. or ,) or the insert/overwrite buttons in the source monitor to cut the clip into a sequence.
5. The merged clip in the sequence will use channel 1 for audio, even though it has been set to use another channel.
6. Now try drag & dropping the merged clip from either the source monitor or from a bin into the sequence. It will now use the audio channel that has been set through modify audio channels.
My workaround is to use drag & drop for now for affected clips, but in the long run this is a pain in the backside.
My question is if this is something that affects other users as well. And while I'm waiting for a fix, if anyone has any suggestions on how to get modified audio channels to work properly, I will gladly listen.
I have filed a bug report for this. I have reproduced this on multiple Windows 7 machines with Premiere Pro CC and on two Macs with both CC and CC 2014.
EDIT to add: I have been in discussion with Rameez from Adobe about this through the support chat and have been told that this is working as intended. He suggested I post a thread about it to see how other editors feel about the functionality. I personally feel that the way it works now makes no sense at all. If others feel the same way, maybe this issue can be fixed in a future update. So please make your voice heard.
EDIT to add: In most usage this might not be an issue at all. But if for example you have external audio on multiple channels and to make sure you have a clean timeline, you wish to remove extra tracks from your merged clips and those extra tracks happen to be any track before the last one(s), you will find that editing the merged clip in in any other way than drag & dropping it in the sequence will result in you losing those last tracks instead of any tracks in the middle that you have disable through modify audio channels. I would think that the audio channel modifications should work no matter what way you cut the merged clip in.
Message was edited by: Jaakko Rinne

Going to try, but here is my workflow and have not encountered any problems until this last P/U days footage. I've been doing things this way because I found having all files in the project was causing it to crash constantly when I was working. I have a new I7' processor IMac with 24 gigs of RAM. And since Premiere does not allow you to have multiple projects open at the same time (Wish this would change. Avid and FCP both allowed multiple projects) I have to do things this way.
Pre-workflow Project File
Label all Video and Audio files to match Scene #'/Takes
Set in points on all video and audio to reflect slate
Merge Clips
Working Project File
Import only Merged Clips into Project. Either via import or copy/paste
Now I've done this workflow from just about the very beginning. Deleting all of the original source video and all audio clips from my working project so only my bins containing my merged clips remain. Have had no problems and edit has been smooth. Did a pickup day last week, followed same steps as I've done in the past, imported the merged clips into my working project and the clips have the audio set to none by default. Now once I go into the sequence I can manually set it and it's there but I cannot play audio in the source monitor which is how I edit, there's no reason I should have to go back to the crappy FCP way of editing doing the copy and paste from a sequence.

Extract single channel from DAQmx Task

Hello,
I have created a DAQmx output task, which contains two channels. Is it possible to extract individual virtual channels from the task to be processed by two parallel processes? I have tried bringing out the Channels Property using a Task Property Node, but I then get the error that the channel is not part of an active task (see attached snippet)
Could anyone advise on a better approach, or how to acheive this functionality - if it is possible?
Regards
Dave
Solved!
Go to Solution.
Attachments:
split out channels from DAQmx task.png ‏34 KB

Sorry, that VI does not make much sense. You have to use a single DAQmx Write for both channels and for 1 Sample mode, you simply have to build an array of the signals as shown below.
Attachments:
two channel write.png ‏12 KB

Setting DAQmx Tasks up in project instead of NI Max

I am writing a labview application to be installed on a PC as an executable file with the Labview Engine. I can put my DAQmx tasks in my project or NI Max. If I put them in my project and I build my application, do I lose the ability to change the IO settings in NI Max independent of my application?
What is the best way to mechanize this with all the features of things like DAQmx tasks being created in my project rather than NI MAX?

id wrote:
I am writing a labview application to be installed on a PC as an executable file with the Labview Engine. I can put my DAQmx tasks in my project or NI Max. If I put them in my project and I build my application, do I lose the ability to change the IO settings in NI Max independent of my application?
What is the best way to mechanize this with all the features of things like DAQmx tasks being created in my project rather than NI MAX?
First. Yes persaisting the DAQmx features to the project removes them from MAX. You will not be able to run them or modifiy them from MAX but only within the Project Context.
This is not always BAD. For instance, no one can "Fat Finger" your configuration or install another Task with the same name that uses different settings. Using the Project provides a context boundary wheras MAX is universally accessable.
Using the Project to store "Tasks, Scales, etc" DOES NOT remove the ability to modify them though. Tasks stored in projects built into an EXEs wind up deployed as a text file in the exes support directory (Exe\Support\NI DAQ\<Something.txt> This is a human readable configuration file that has the tasks settings in it. If you need to change a setting (like increase a sample rate or change a physical channel) you can edit the file and the exe will use the new settings.
This is not always GOOD For instance, if the test system suffers a fault, MAX cannot selectively control the IO channels for troubleshooting.
Knowing the pros and cons of each method will help you work within your team to develop the best approach for your needs. I've recommended each approach to various clients. (And been right both ways!)
What I've never recommended is creating tasks programatically. However, I can see some use cases where hiding the configuration from everyone (on a removed BD) might be desired in a highly regulated enviornment where a possible change to a Task Property Could change code validation and the ECO process requires removing any possible "Hidden" access to the config files (Although a hash on the EXE folder could be used to disable testing)
Jeff

Would you Open and Close DAQmx tasks within a function or Globally

Hi Guys,
This should start something.
The subject is DAQmx Tasks.
If you were writing a function that is called many times, say MeasureVolts (double *Value) to obtain a reading from an Analogue Input Channel.
Would you.
1. open and start the task inside the function, do the measurement and then close the task inside the same function.
or
2. open the task globally and later do the measurement inside the function using the global task then close the task only when the application is closed.
I am mostly concerned with the overhead of task generation and closing, what do you guys and girls out there do?? and what is the general opinion?
I would appreciate your views.
Regards
Paul.

I would definitely NOT keep configuring and clearing (I think that's what you mean by open and close) the same task over and over. I would configure once, read many times in my main app, then stop & clear once.
I typically like to package such data acq into an "Action Engine" that keeps track of its own DAQmx task id so I don't need to sling that task id wire around into multiple parallel loops / vi's. Attached is a very stripped-down example for Digital Input.
I would typically do more with error testing and would make the "Action" enum into a typedef custom control, but this gives you the basic idea. The action engine approach works very nicely when there's a small # of different kinds of input parameters and output info needed to support all the necessary action cases. When you start needing a large number of differnent kinds of inputs and outputs to support the desired actions, then you start having difficulty with (1) having enough terminals to wire and (2) remembering which inputs and outputs are meaningful for which actions.
-Kevin P.
Attachments:
DI Action Engine.vi ‏75 KB

Creating a new DAQmx task after building to EXE

Should I be able to create a new DAQmx Task while running a VI containing the DAQmx Task control that was built as an EXE?
I can't but would like to know if there is a work around or if I am doing something wrong. See the attached screen shots.
When I am not running the VI, I can right click the Task front panel control and select "New NI-DAQmx Task" -> "Project" or "MAX", but when it is running or I am using the VI built as an EXE (running or not) I can't. In the EXE I am able to click the Task drop down box -> "Browse..." -> "Create New..." -> "MAX Task" but nothing happens when I click on "MAX Task".
I would like to be able to create a new task in the software to use different channels and signal types on the fly. The goal is to build a program setup similiar Signal Express but include some on off controls for some machinery and scale it down and customize it so that it is easier to show people how to use it.
Thanks
Attachments:
block diagram.png ‏30 KB
front panel.png ‏25 KB
exe front panel.png ‏26 KB

When running your exe, you'll be able to select from tasks created in MAX. Instead of right clicking on the task control, try creating the tasks you want directly in MAX (under Data Neighborhood right click on DI-DAQmx Tasks to create a new one). Tasks that you've saved in MAX will be selectable in the DAQmx Task Name control.

NI-DAQmx task works in MAX or DAQ Assistant test panel but not in LabVIEW

I am attempting to read a single AI channel from a PCI-6024E card via an SCB-68. I have created a NI-DAQmx Analog Input Voltage Task in MAX for this channel, sampling in contiuous aquisition mode at 100 kHz, 10000 samples at a time, with RSE terminal config. If I use the Test feature from MAX, the channel acquires data as expected.
In LabVIEW, I call this task using an DAQmx Task Name Constant. If I right-click this constant and select "Edit Task", the Daq Assistant opens and I can use the Test feature from the DAQ Assistant to see that the data is still being acquired as expected.
However, when I try to programmatically read this channel in LabVIEW using the VI "DAQmx Read (Analog Wfm 1Chan NSamp).vi", the VI returns a constant DC value of 500 mV, which I know is incorrect (I can monitor the signal across the two terminals in the SCB-68 with a DMM to know that the signal coming in varies as expected, and as I read using the test panels). This erroneous reading occurs even if I make a new VI, drop the task name constant on the diagram, right-click the task name constant and select "Generate Code - Example" and let LabVIEW create its own acquisition loop (which is very similar to what I already set up, using the "DAQmx Read" VI).
Any ideas why the Test Panels work correctly but the LabVIEW code does not?

Hello bentnail,
I'm not sure why the test panels are readin the value correcly but the LabVIEW code does not, but there are a couple of things we can try.
1) What happens if you just use the DAQ Assistant and place it on the block diagram? Does it read out the correct values?
2) Try running a shipping example that comes with LabVIEW. "Acq&Graph Voltage-Int Clk.vi" should work well.
3) What kind of signal are you expecting to read (peak to peak voltage, freqeuncy, etc.)?
Thanks,
E.Lee
Eric
DE For Life!

DAQmx task does not start on RT target

I cannot programmically start a DAQmx task on an RT target. The PXI-8140RT controller hangs on either the DAQmx Start Task.vi, DAQmx Read.vi, or the DAQmx Create Timing Source.vi, depending on the level of complexity I try to use. Any suggestions on what would cause this?
The vi running on the target is based upon the wizard created target-multi rate-variables-fileIO.vi. I cannot stop the vi once it hangs; I can only close it. I have to restart the controller to reestablish communication. I have tried DAQmx tasks created using MAX, created programmically, and created from a front panel task control. The tasks test ok using the MAX or the DAQ Assistant. For now I am trying to measure one RTD channel.
The RT system consists of the PXI-8140RT, a PXI-6259 M-series controlling a SCXI chassis, and the SCXI-1102B and SCXI-1581 pair capable of measuring 32 RTD's. There are two other modules in the SCXI chassis which aren't being used yet; a SCXI-1162HV and SCXI-1163-R. The target and host are running LV Real-Time 8.01 and NI-VISA 3.5. The host has NI-DAQmx 8.0.1f while the target has V8.0.0, apparently the lastest available.

The VI didn't generate an error message. Nor was there a message in the RT error log. I guess it froze before an error could be generated. I used the DAQ Assistant Express vi in a totally new project. I have since converted this to code and added features to make it more like my original project. The new project is working. I suspect something went wrong with the original project. I've tried to edit the original project to more closely match the new one and it still dies. Guess it's time to put it to bed.

Design Suggestions for Multiple DaqMX Task Streaming App?

I'm working on a LabVIEW application in which I'm streaming high-speed data to disk from multiple PXI devices simultaneously. Each device has its own DaqMX task, and all tasks stream to the same file. The PXI device configuration (which devices are in the chassis, which slots they're in, and which channels to read from each device) is determined at runtime.
Does anyone have a suggestion for a design model for this? To make matters worse, I'd like to be able to specify a channel to monitor its data during the streaming. I'm thinking the Producer-Consumer model is the basic approach, and I'm at the point where I have an array of DaqMX tasks, one for each device. I could probably extend that array to be an array of clusters containing:
   1) DAQ Command (e.g. Initialize, Start, Stop, Acquire, etc)
   1) Task ID
   2) Control reference to 2-D array (where each DaqMX read can be stored)
   3) Array of channel names (to allow selection of channel to be monitored
This could be passed as notifier data, to a data collection subVI, but the part I'm struggling with is finding the best way to run X number of tasks in parallel, where X is not known until runtime.
Any suggestions would be appreciated.

Thanks for the input. With regards to the file format, the decision has been made by my superiors not to use TDMS - unfortunate, but NI hasn't provided the information to write a MatLab file reader, which is a requirement. So, I've created a custom file format tailored to the needs of my application, but generic enough to be used for other apps. With it, I've been able to stream 8 channels at 800KHz (4 channels each from 2 PXI-6120s) without breaking a sweat. However, the performance varies greatly depending on which slots the cards are in (but that's a whole different discussion - see the PXI forum for that one). Once NI solves that one, I'll feel a lot more comfortable.
I have already made reentrant subVIs that can perform a specific DAQ task. The problem with a for loop is that the VI sits and wait for a start trigger, then acquires the streaming data. I can't start the next VI because I'm in the first one. I thought about creating a data collection VI, and this VI would start up to 6 other VIs in parallel, based on how many and which cards were present. It's a bit messy, because each slot can contain one of two devices, so I'd need to check which type it was before calling it. I'm thinking I'll have to create the task list and the references to the data in the main GUI loop, and then pass this using a notifier or queue to the data collection loop.

Full information about DAQmx Task Name - How get?

Labview 7.1 (information required for solve problem)
I put in my application a DAQmx Task Name for fast configuration but i want put all information about task in a txt or spreadsheet file. But in Labview 7.1 haven't VIs like (http://zone.ni.com/devzone/cda/tut/p/id/3079):
- DAQmx Info Query
- General DAQmx channel Info
- General DAQmx TEDS Info
I'm using Analog Input (Voltage and Accelerometers) with several configurations and I need register all data of configuration to re-execute in the future or know about how acquisition data were gotten.
I think that solve is in property nodes(DAQmx Task, DAQmx Channel, DAQmx Timing), but I believe will be hard work to make. Somebody has this working?
Leonardo de S. Cavadas
Maintenance Engineer and Inspection - Bureau Veritas do Brasil
Engineer Metallurgist with emphasis in Advanced Materials
Technologist in Computer Science

Sorry about that, I haven't checked if they were made only for LV 8 and later. Attached is a zip file with all the VIs converted to the version 7.1.
Some of them were not successfully converted and are presenting fatal errors when opening, probably because they have something not available in 7.1. But I'm sending you anyways, because the three VIs you mentioned in your first post that you wanted, are working fine in LabVIEW 7.1.
- DAQmx Info Query
- General DAQmx channel Info
- General DAQmx TEDS Info
Please let me know if this is of any help for you or if I can do anything else in this case.
Best Regards
Andre Pereira
Attachments:
DAQmxTaskInfoQuery.zip ‏586 KB

Is it possible to create a list of NI-DAQmx tasks used in a VI in LV7.1?

Hello,
I was wondering if there is a built in function for Labview 7.1 that would allow me to generate a list of DAQmx tasks or global channels that are being used in the VI.
Thanks,
Steve

Welcome to the Discussion Forums,
Steve!
Since I’m a visual person, I wanted
to make it clear where these properties are found by posting a picture.
I also wanted to clarify and say
that these properties show the global channels and tasks saved on your system.
They do not indicate which are used by a specific VI. This is because global
channels are not bound to any particular VI. Any indicator you could include in
your VI would just return the names that are being assigned as inputs. So the
best way to know what’s being used in your VI is to look at what the inputs
are.
I hope this helps. If this isn’t
exactly what you’re looking for, will you please post again and clarify your
application?
Message Edited by Mark E on 11-07-2007 09:29 AM
Mark E.
Precision DC Product Support Engineer
National Instruments
Digital Multimeters (DMMs) and LCR Meters
Programmable Power Supplies and Source Measure Units
Attachments:
System_node2.JPG ‏106 KB

-200428 - Modifying a channel in a predefined DAQmx task

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