DAQmx operations

[GURO]

Hi guys, i'm started with DAQmx with VisualC and it's fantastic. The documentation is not very well designed on some topics, can someone answer this questions.
1- Global channels and scales can be created programmatically?
2- Is it possible to configure two tasks with the same global channel?
3- How to scale a raw channel value with a global scale?
Have a nice day.
Thank you
Roberto Guerzoni

[SarahM]

Hi Roberto,

I�m glad you�re enjoying DAQmx. Here�re some answers to your questions.

1. You can create channels and scales programmatically but they can only be used within the scope of the program they�re created in. Here�s a link to a document that describes this in detail. Although some names are LabVIEW specific the concepts apply to programming DAQmx in general.

Can I Save Virtual Channels Created in LabVIEW to the NI-DAQ Configuration File?

2. You can have two tasks with the same global channel but you won�t be able to have them running at the same time. You can however read the same physical channel multiple times in a single scan. Here�
s a link to a document that discusses this in more detail.

Can I Sample One Channel Multiple Times Before Switching to the Next Channel In My DAQ Channel List?

3. You can apply the global scale to your channel by passing in the name of the global scale as the customScaleName parameter when you create your channel programmatically. If you�re using a global channel created in the Measurement and Automation Explorer (MAX) you can configure the channel to use the global scale in MAX or programmatically apply it. For example if you have an analog input global channel you can programmatically apply a scale using the DAQmxSetAICustomScaleName function.

Please feel free to post back if you have any additional questions.

Good luck with DAQmx and have a great weekend!

Sarah Miracle
National Instruments