NI-DAQmx Global virtual channel constant not working in "LabVIEW 2016"

[roopesh689]

Hello, 

I am using "NI USB-6001" for my application, and created the code in "Lab view 2016" for data acquisition. I will modify the code and test it with a  new 6001 every time.This VI is present inside a project.

When i drop and click on the pull down arrow of "Global virtual channel constant" to select the lines to read, nothing is happening. Even "Browse " is not listed there.

Is it related any Max Configuration ?

The "DAQmx Task Constant" is also not working even after the tasks were created in MAX.

I already have the old "Global virtual channel constant"  in the code, and when  clicking on the drop down menu , nothing happens. i have deleted the old "Create Channel VI" as well and created a new one, reinstalled the NI DAQmx several times. but still the problem is not solved.

Any one faced this problem ?

I am facing this problem in more than one PC both updated with NI DAQmx ver.18

[oscarfonseca]

Hello oopesh689,

There is a difference between a Global Channel and a DAQmx task as explained in: Channels and Tasks in NI-DAQmx

In the image you attach (max config.jpg) you show 4 DAQmx tasks and zero Global Channels. I wouldn't expect the DAQmx Global Channel constant to show anything, since there are no Global Channels defined in NI MAX.

If you want to use the data acquisition settings you have in NI MAX, I recommend you use a DAQmx Task Name Constant.

Additional resources to check out:

• Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications
• Answers to Frequently Asked Questions about NI-DAQmx and Traditional NI-DAQ (Legacy)

All the best,

[roopesh689]

Thank you for the comment.

I have reinstalled the LABVIEW development software  and Daq Mx 16 drivers. 

As you said , i have created the Global virtual channels as well as tasks in MAX and saved it.

Now that i have created everything , it should appear in the vi at the channel or at task constant right?

Please see the attached images . Even the channel controls ,constants , task constants does not shows anything when you click on the pull down button.

Am i missing any drivers?

[oscarfonseca · Accepted solution]

roopesh689,

Can you try with the VI I attached? It has different constants, and I would expect it to show your Global Channels and Tasks in the dropdown.

If all of them are still empty, even when your device is plugged to the computer, I would follow the next steps:

1. Backup your NI MAX Configuration data: Export/Import the System Configuration in Measurement & Automation Explorer (MAX)
2. Reset your NI MAX database: How to Fix or Reset the NI MAX Database File

Keep us posted. All the best,

[roopesh689]

Thank you.

As per the steps you said  i made a back up of the MAX configuration. Reset the Max Configuration.

Then imported the old configuration.

It is now working fine.