@NIerrors wrote:
I have another question. Won't I have to worry about synchronization using a producer/consumer architecture? Would I still be able to produce data at a constant rate with an accurate time column?
Sorry, I'm attending a conference, so can't always respond "quickly". Your Producer loop should consist of a DAQmx Read function that feeds its output (which should be an array of samples, so that the loop naturally "fires" at a reasonable rate, say from 1-10 times per second) directly into a Queue (to be sent to the Consumer). This means that the Producer loop has nothing else to detain it, so you can expect that it will reliably fire "on time".
Contrast this with having additional code that tries to write the data to a file inside the same loop. The writing cannot start until the data are present (obviously), so the time required before you can finish the loop and take the next sample is increased by the (possibly variable, and OS-dependent) time it takes to do the write to disk. No guarantee that you will have "an accurate time column".
There are a variety of ways you can choose to write your data to a file. Some are very fast, some embed additional "meta-data" that makes it easier to get the data back out without having to know the format of the data going in, some are inherently "human-readable" (text), others are only "machine-readable" (binary). There are a number of discussions about the pros and cons of the various LabVIEW Data Formats in the LabVIEW Help -- you can also probably find useful information by doing a Web search for LabVIEW File Formats.
Just because an NI Support Engineer suggests something doesn't mean it is the optimal method for you.
Also, you do not need 46 Create Virtual Channel functions. I haven't looked at your VI recently, but if you create a Task, you can designate the channels that the Task utilizes. For example, if you have a 32-channel Analog Input device, you can specify that you want to acquire samples from Channels 0 .. 31. The only "catch" is when you treat channels as a group this way, you need to use a single time base for all of them. Note that you can have individual scaling on a per-channel basis -- experiment with Task creation (you can do this in MAX or from the LabVIEW Project, New/Task).
Bob Schor
