How to measure frequency on PFI0 (DAQPad-6015)

[sievi]

Dear All,

I am trying to measure the frequency (or the period) of a digital input signal which is connected to the PFI0 input on a DAQPad-6015. I tried to modify one of the supplied examples (C:\Program Files\...\MeasDigFrequency_LowFreq1Ctr.sln) in order to use the PFI0 input.

I added the following code to the measureFrequencyButton_Click procedure:

DaqSystem.Local.ConnectTerminals("/Dev1/PFI0","/Dev1/ctr0Source")

after the Try statement. When running the program I get the error message:

Specified route cannot be satisfied, because it requires resources that are currently in use by anther route.

Property: NationalInstruments.DAQmx.CIChannel.CounterTimerbaseSource

Property: NationalInstruments.DAQmx.CIChannel.CounterTimerbaseActiveEdge

Source Device: Dev1

Source Terminal: MasterTimebase

Task Name: CITask

Status Code: -89137

My questions:

1. Is this the right approach or should I use another procedure?

2. Is that the right place (procedure measureFrequencyButton_Click, before creating myTask) to make a connection of DAQ terminals?

Any help is appreciated.

Detlef S.

[sievi]

Sorry, I forgot:

I am using Visual Basic .NET 2003 and NI Measurement Studio 7.1 as development system.

Detlef S.

[ManuelW]

Hi Detlef

Im not sure but have a look at this page, maybe it will help you:

http://digital.ni.com/public.nsf/websearch/CF592CB42924F9B986256F320053C5C7?OpenDocument

Manuel

[sievi]

Hi Manuel,

thank you. Yes, I have seen that link and that is the reason why I wrote the code

DaqSystem.Local.ConnectTerminals("/Dev1/PFI0","/Dev1/ctr0Source")

instead of

DaqSystem.Local.ConnectTerminals("/Dev1/PFI0","/Dev1/ctr0").

Maybe I should use the "internal name" for PFI0 also, but I did not find any information about that one (neither online at the NI internet pages, nor in any help file installed on my PC together with NIMS).

Regards,

Detlef

[sievi]

For those who are interested in the solution of my application (see above):

I added the following line after the myTask.CIChannels.CreateFrequencyChannel statement:

mytask.CIChannels.Item(0).FrequencyTerminal = "/Dev1/PFI0"

and now I am able to run the demo program measuring the frequency of the PFI0 input signal.

The DaqSystem.Local.ConnectTerminals statement is not necessary.

Best regards,

Detlef