Error -200486 "specified channel is not in Task"

[Dennis_Knutson]

I don't understand why you are using the Save Global Channel instead of Save Task.

[richjoh]

It appears to me in latest DAQmx (Labview 2011) you don't need to use DAQ assistant to configure an NI DAQ for measurement. I thought I'd go ahead and programatically do this but the example doesn't work whenever I send a multi-channel Task (or does it only work with 1 Task/1 Channel) as I have performed. Is this intentional? When its time to distribute MAX configuration on PCs the Labview will generate the hardware configuration (no DAQ assistant necessary). Generating local virtual channels work just fine.

From LV Help:

"

Local and Global Virtual Channels

Virtual channels created with the DAQmx Create Virtual Channel function/VI are called local virtual channels and can only be used within the task. With this function/VI, you choose the name to assign for the virtual channel, which is used in the rest of the NI-DAQmx software framework to refer to the physical channel.

If you create virtual channels with the DAQ Assistant, you can use them in other tasks and reference them outside the context of a task. Because these channels can apply to multiple tasks, they are called global virtual channels. You can select global virtual channels with the NI-DAQmx API or DAQ Assistant and add them to a task. If you add a global virtual channel to several tasks and modify that global virtual channel with the DAQ Assistant, the change applies to all tasks that use that global virtual channel. You must save the changes before they become globally available.

"

[richjoh]

This says "DAQmx Save Global Channel VI saves either local or global channels to MAX" . Notice its Labview 8 and channels is plural or either this is a typo. Well I use (LV2011) multi-channel to the VI and I persistantly get error. A single channel to the VI work just fine. I need to setup 16 channel of the 6218 DAQ for voltage measurement and heck make the channels virtuals. Anyhow, I've already moved on and wanted to point the multi-channel issue out.

[Dennis_Knutson]

---

@richjoh wrote:

It appears to me in latest DAQmx (Labview 2011) you don't need to use DAQ assistant to configure an NI DAQ for measurement. I thought I'd go ahead and programatically do this but the example doesn't work whenever I send a multi-channel Task (or does it only work with 1 Task/1 Channel) as I have performed. Is this intentional? When its time to distribute MAX configuration on PCs the Labview will generate the hardware configuration (no DAQ assistant necessary). Generating local virtual channels work just fine.

From LV Help:

"

Local and Global Virtual Channels

Virtual channels created with the DAQmx Create Virtual Channel function/VI are called local virtual channels and can only be used within the task. With this function/VI, you choose the name to assign for the virtual channel, which is used in the rest of the NI-DAQmx software framework to refer to the physical channel.

If you create virtual channels with the DAQ Assistant, you can use them in other tasks and reference them outside the context of a task. Because these channels can apply to multiple tasks, they are called global virtual channels. You can select global virtual channels with the NI-DAQmx API or DAQ Assistant and add them to a task. If you add a global virtual channel to several tasks and modify that global virtual channel with the DAQ Assistant, the change applies to all tasks that use that global virtual channel. You must save the changes before they become globally available.

"

---

You have never been required to use DAQ Assistant to configure. You have never been required to save a task to MAX or to create Virtual Channels. The only thing I have ever had in MAX has been the device name. Nothing else has been required to me to export and distribute. What is your express reason for having the virtual channels in MAX if you are actually configuring everything in the VI?

[richjoh]

I don't care for DAQ assistant. I get error -200486 when

"using NI-DAQmx 9.0 and later, you can create an Internal DAQmx channel in LabVIEW and save it as an NI-DAQmx Global Virtual Channel programmatically. " Does it (the VI) do multi-channel save, thats the question if so why does the Save Global Channel error? Now I guess I could save Global channels one at a time.

"If you create virtual channels with the DAQ Assistant, you can use them in other tasks and reference them outside the context of a task. Because these channels can apply to multiple tasks, they are called global virtual channels. You can select global virtual channels with the NI-DAQmx API or DAQ Assistant and add them to a task. "

[Dennis_Knutson]

Please don't quote the help back. I've read it and you've also been told that the function is only for a single channel. Nor is your reference to an internal channel at all relevant. An internal channel is not what you are using. A globabl channel is by definition, a single channel. A task may consist of more than one channel.

What I asked you was why you find it necessary to save the channels as global channels in the first place. You have said that you are configuring everything in your VI. Where else are you planning on using the global channels?

[richjoh]

OK you mean the VI "DAQmx Save Global Chanel" saves a single Global channel only and not a multi-channel string. Exactly what I've ask for early on. That would explain the error. I'de have to rewire the VI so that a single physical channel is input into "DAQmx Create Channel", which does do multi-channel physical channel and feed its output 1 at a time to the "DAQmx Save Global Chanel" that doesn't do multi-channel. I'd say that need VI needs to fixed to handle multi-channel physical address.

Once I save the Global channels any Task can reference the channel by name. Its all spelled out in the DAQmx help, isn't this obvious why I want to save as Global Channel.

What is your source on the information of "the function is only for a single channel". I don't follow this part of your response "Nor is your reference to an internal channel at all relevant. An internal channel is not what you are using. A globabl channel is by definition, a single channel."  Did you mean Virtual channel? Where may I find this definition of "A global channel is by definition a single channel".

Anyhow, it appears two sources mention the Save Global VI is intended for single channel and maybe this should be made clear on the next upgrade.

[PeterGC]

richjoh,

Yes, the DAQmx Save Global Chanel saves a single global channel.  You cannot assign multiple channels to this global channel.  This is why the error is thrown.  Sorry, if that I wasn't clear earlier.

[richjoh]

OK, therefore for now it must be 1 (physical) Channel per Global Channel. Got it. Below is something that works for now.

[cjdsus]

이 오류는 어떻케 해야된느것입니까.

새로 깔았는데 ..이오류 때문에..작업이 안되네용