12-06-2007 07:25 PM
12-10-2007 09:11 AM
Hello ASteiner,
I see you are interfacing with a 3rd party data acquisition device in LabVIEW. I have a couple questions regarding the device and your application.
1. What is the 3rd party data acquisition device that you are using? Is the device supported by DAQmx?
2. You mentioned having to call an external library function to initiate the generation of your signal. Is this for specific functionality or is this because the generation is not supported by DAQmx?
3. Is there a function call available for the analog read as well?
4. What is the DAQmx error code that you receive when the task fails?
5. What channel are you triggering off of and what is the timeout rate?
Please answer these questions as thoroughly as possible. Also, it would be helpful if you could post a screenshot of the code in question so that I can see the overall structure and flow of the application.
Regards,
12-10-2007 09:32 AM
First of all I have to clear up some misunderstandings about
the hardware setup I am working with. It is probably my fault because my first
post was admittedly a bit unclear. The 3rd party hardware is not a DAQ device,
it is an RFID reader. I am using DAQmx and a NI USB-625x series DAQ to read a
signal generated by the RFID reader. I have to send a command to the RFID
reader using the DLLs provided by the manufacturer to initiate the signal the
DAQ is triggering from and I am using the Call Library Function Node to
interface with the DLLs. That hopefully answers the first two questions.
The error generated by DAQmx is Error -200284, which indicates that some or all
of the samples were not acquired before the task terminated. I have done some
additional work with the interface between the RFID reader analog signal and
the DAQ and there seems to be some issue there that affects the DAQ's ability
to sense and trigger off of the analog edge event I have set up in the code.
However, if I monitor the analog out signal with an oscilloscope while
attempting to run the acquisition routine, everything works flawlessly. This is
leading me to think that it isn't necessarily anything wrong with the LabView
code but rather a hardware issue with the connection between the DAQ and the
RFID reader that I should probably post about in the DAQ forums. Perhaps there
is some nuance with the terminal configuration I am unaware of that the high
impedance of the oscilloscope corrects...
12-10-2007 09:34 AM