Hi, I'm still very new with Labview, and I'm trying to do something that seems pretty complicated to me. I've already implemented some code that collects data from a DAQ and plots it. Another thing this does is save the data coming off the DAQ. I'm now trying to add functionality to give the user the option of running from the DAQ or from a saved file, and I'm having lots of trouble. My queue still works when I choose to run an acquisition, but it doesn't work when I try to open the saved file. I've attached both the original code and what I'm trying to do. I'm not attached to the method that I picked to choose between acquiring and playing back data, so if there is a better way (and I'm certain there is) please let me know. Thanks,Anthony

Thanks for the explanation of your data types. I'd still recommend that you try to be consistent about your data types; if you never use any floating point values, then change your constant representations and eliminate the orange wires. Also, I still think your problem is somewhere in the way you're reading your data. Correct me if I'm wrong, but it looks like when you read the data from the DAQ card it's an I32, but when you read it from your file it's a U8 (implicitly converted to an I32). Then you divide that value by 256, which works fine for the I32 from the DAQ card, but produces only 0s for the U8 values read from the file (the maximum of value of a U8 is 255, so dividing produces a values less than 1, which gets cut off to 0 when you convert to U8 before subtracting 32 and sending it to the queue). EDIT: also, be careful using the text file functions for binary data, even if you think it's all ASCII. You have the "Convert EOL" option checked, which means that LabVIEW may modify, insert, or delete values that match the ASCII code for an End Of Line character. Consider using the binary file functions instead.Message Edited by nathand on 10-15-2009 05:19 PM

LabVIEW

Issues with queues

Solved!

Author

You were correct. I completely forgot that I wasn't using the low order 8 bits on my DAQ for the byte input. I was using the 2nd 8 bits, hence the division by 256. I moved that division and the type conversion to U8 inside the conditional statement, and it now works like a charm. Thats a good call about being consistent with data types. I didn't realize thats what I was doing when the lines were different colors. I'm going to go in and fix that.

Fortunately the data output was defined in such a way that all of the characters are symbols, characters, or numbers, but I may look into the binary file functions anyway.

Thanks again for your help.