CI freq for multiple counters

[NoelRK]

I have two angular encoders and want the frequency of both encoders (or the angular position of 1 and the frequency of the other, both cases yield the same error). I have one CI freq given Dev2/ctr0 as the counter and the other CI freq (or CI Angular Encoder) given Dev2/ctr1.

I'm given:

Error -50103 occurred at DAQmx Start Task.vi:7

Possible reason(s):

The specified resource is reserved. The operation could not be completed as specified.

Task Name: _unnamedTask<18>

Why is it telling me the resource is reserved? I am using two different counters(Dev2/ctr0 and Dev2/ctr1)?

[Chris_D]

Hey NoelRK,

This error could be caused by a couple of different reasons. If you have have been switching back and forth between running a DAQmx and Traditional DAQ you may need to reset your driver. Please see the KB below.

Error 50103 at DAQmx Start Task
http://digital.ni.com/public.nsf/allkb/78B717D49592D7238625703B00797E07?OpenDocument

Also, when you are doing your counter frequency measurement can you confirm that you are doing the 1 counter method? It as also possible to do a 2 counter method and doing this may cause the 50103 error if you are using one of the counters in another task.

[JB]

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Also, when you are doing your counter frequency measurement can you confirm that you are doing the 1 counter method? It as also possible to do a 2 counter method and doing this may cause the 50103 error if you are using one of the counters in another task.

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See this document for more details about the 3 available frequency measurement methods. Two of them use 2 counters !

[NoelRK]

Thank you for your comments. I now understand why Labview was telling me why I was using reserved resources. I was using CI freq that required two counters.

Noel

[NoelRK]

Out of curiousity why does the 2 counter methods cause this problem? If I use the angular position for Ctr0 which require inputs to PFI0 (A) PFI1(B) and PFI2(Z) and use a 2 counter method (high frequency or large range) for Ctr1 that only requires PFI3 (A) the two counter method still only requires one input so why the resource conflict.

Noel

[JB]

The problem is not related to the physical connections (PFI lines) but to the counters on the DAQ board. Most of the DAQ interfaces have only two counters.
One counter will be used for the angular position measurement and both for the frequency measurement. 1+2=3 ! Therefore both tasks can't be executed simultaneously on an interface with only two counters !

[NoelRK]

That makes sense now that you've pointed it out. Thank you very much.