Can I change the default counter input channel if I used DAQ assistant?

[civet]

Ok, I'm new, but my searches haven't given me an answer to this.  I'm measuring frequency of a digital signal using counters on a 6220 board and found it very easy to set up using the DAQ assistant in Labview 8.2.  My problem is that I have 4 (sometimes 😎 different signals that I want to measure which seems ok according to the help system, if I could find a way to alter the Counter Input:Frequency:Input Terminal attribute.  Right now, I'm stuck using the two default values of PFI 9 and PFI 4.  Is it possible to alter the input terminal if I used DAQ assistant or do I need to build something up by hand?  If I do need to build this by hand, are there any examples where people have altered the input terminal attribute?

Thanks for any insights.

Roger

[Robert_F]

Hello Roger,

There is no way to change the physical channel of the DAQ Assistant programmatically for this application.  You would have to use the DAQmx subvis to get this functionality.  If you Right-Click on the DAQ Assistant and select Generate NI-DAQmx Code, it will convert your DAQ Assistant into its corresponding DAQmx subvis. 

You can not change the physical channel of the counter without stopping the task first.  After you stop the task, you can change the channel through a property node (DAQmx Channel Property Node >> Counter Input >> Frequency >> Input Terminal), then start the task again. 

You do have two counters on the PCI-6220, which means that you can only measure two signals simultaneously.  The number of signals that you can measure is dependant on how many PFI lines you have access to.  You can only measure a signal on PFI lines: 1-3, 5-7, 9-10, 15-16.  If you wanted to measure 8 signals simultaneously, then I would recommend a PCI-6602.  This board has 8 counters, which means that you can read in 8 different signals.

[civet]

Thanks Rob, 

I started down the path you suggested, but I didn't know about needing to stop and start the task again when changing input terminals.  I don't need to measure all 8 signals exactly simultaneously (yet), just nearly at the same time will do at first, so I think this will work for me, for now.  Thanks for pointing me at the 6602 board.  I look at it for the future.

Roger