LabVIEW
DAQAssistant or DAQmx?
Hi Dana,
DAQ Assistant is a "high level" tool that is a little like a Wizard. When you drop a DAQ Assistant block onto your diagram, it starts the wizard program. From the wizard, you select the functions you want that specific block to perform.
By DAQmx, I'm guessing that you're referring to the lower level tools rather than just the drivers themselves. The DAQmx tools can perform the exact same functions as the DAQ Assistant. But they offer much more control over the details.
What you chose for your particular project is a matter of choice really. Personally, I use MAX to create Virtual Channels and Tasks for my projects. Then I'll use the DAQmx Read or Write blocks and reference the Task or Virtual Channel I setup in MAX.
If you've never used MAX before, double click on your Measurment and Automation icon or look for NIMAX.exe in the National Instruments\MAX folder. In the left hand pane you'll see a sub-folder called Data Neighborhood. This is the sub-folder where you create your Tasks and Virtual Channels.
Not everyone is a fan of this method. Others prefer to set everything up in the block diagram of their code. In my case, we often end up making a lot of changes to machines long after they've been delivered. Sometimes IO changes a lot. In MAX I can make changes on a global level for my projects. Sometimes we move inputs or outputs around. With this method, it's very easy.
Hopefully that helps a little.
Good luck.
DAQ Assistant is a "high level" tool that is a little like a Wizard. When you drop a DAQ Assistant block onto your diagram, it starts the wizard program. From the wizard, you select the functions you want that specific block to perform.
By DAQmx, I'm guessing that you're referring to the lower level tools rather than just the drivers themselves. The DAQmx tools can perform the exact same functions as the DAQ Assistant. But they offer much more control over the details.
What you chose for your particular project is a matter of choice really. Personally, I use MAX to create Virtual Channels and Tasks for my projects. Then I'll use the DAQmx Read or Write blocks and reference the Task or Virtual Channel I setup in MAX.
If you've never used MAX before, double click on your Measurment and Automation icon or look for NIMAX.exe in the National Instruments\MAX folder. In the left hand pane you'll see a sub-folder called Data Neighborhood. This is the sub-folder where you create your Tasks and Virtual Channels.
Not everyone is a fan of this method. Others prefer to set everything up in the block diagram of their code. In my case, we often end up making a lot of changes to machines long after they've been delivered. Sometimes IO changes a lot. In MAX I can make changes on a global level for my projects. Sometimes we move inputs or outputs around. With this method, it's very easy.
Hopefully that helps a little.
Good luck.
Dana,
I personally prefer to use the DAQmx vi's and try to avoid the DAQ assistant. While the assistant is a great way to quickly get something running, it does not get the best performance from your DAQmx hardware. I guess I may have control issues. 
Suggest that you read the section in the DAQmx docs that deals with the Task State Model.
You mention acquiring signals from several channels. What kind of signals do you need to record?
Hello again Dana,
This problem is a little unusual, and it's difficult to guess what might be happening without actually seeing it. But I have a couple of ideas.
First; Whenever you create or alter a channel in MAX, you must SAVE any changes you make before those changes will apply to anything other than the preview window. This one has caught me many times. The Save button is in the top left hand corner of the main panel.
If that's not the case, it might help if I saw a screenshot of the code you're using to display your graph. I'm not at work just yet and while I do have LabVIEW for Linux here at home, it does not have MAX. (yet!) So I can't really poke around that until later this morning.
This problem is a little unusual, and it's difficult to guess what might be happening without actually seeing it. But I have a couple of ideas.
First; Whenever you create or alter a channel in MAX, you must SAVE any changes you make before those changes will apply to anything other than the preview window. This one has caught me many times. The Save button is in the top left hand corner of the main panel.
If that's not the case, it might help if I saw a screenshot of the code you're using to display your graph. I'm not at work just yet and while I do have LabVIEW for Linux here at home, it does not have MAX. (yet!) So I can't really poke around that until later this morning.
