error 50103

[MarieV]

Hello,

I am quite new to Labview and I am experiencing problems related to error 50103.

I would like to measure the RPM and the angular postion of an IC engine, using NI 9401 and NI 9704.

First, I created one task to measure the angular position with the 'DAQ assistant - angular position', reading cntr1  (PFI 4, 5 and 6), wich perfectly worked.

And then I used another task to measure the frequency with the 'DAQ assistant - frequency', reading PFI4.

These two tasks worked well when I seperatly run them, but then I get the error 50103 if I want to measure frequency and angular position at the same time.

After reading in the forum, I understood that I can only have one DAQ task per DAQ device. I know it is possible to add more that one channel in one task, but here the DAQ assistant is not of the same type (angular position and frequency).

If you could help me on thaht issue, I would be most grateful.

Thank you and sorry for my poor english.

[crossrulz]

Can you post a screen shot of that error.  I'm not finding that error in LabVIEW.  I also can't find the 9704 on the NI site.  Are you sure that's the right model number?

Are you using the same module for the position and frequency measurements?  Notice that they both use PFI4.

EDIT:  Found the error on the NI site: http://digital.ni.com/public.nsf/allkb/485201B647950BF886257537006CEB89

Resource is reseved.  It sounds like my guess was correct.  Make sure you are using different modules.

[Dennis_Knutson]

Yes, that is a common error and you are right, you can only have a single task for a common resource (i.e. analog input) and the solution is to have both channels in the task. Simply clicking on the 'Add Channels' button at the top of the Assistant will bring up the dialog to add another channel of whatever measurement type you want.

[MarieV]

Thank you for your reply Crossrulz.

I am sorry and you are right, the chassis is NI cDAQ 9172, my mistake.

My problem is I don't know how I can use two different modules ; I measure the angular position with an optical encoder. PFI 4 and PFI 6 receive two channel quadrature outputs, and PFI 5 receives a third channel qudrature output. This last channel (Channel I) is significant because a pulse is generated once for each full rotation of the wheel : it can reset the angle from 360 to 0 to each rotation. I really need to acquire these three channels to get the angle.

For the frequency, I use PFI 5, the index channel of the encoder.

I know I get the error because I am using at the same time PFI 5 for the angle measurement and for the frequency. Maybe I can split the wire of channel I (I mean physically), and use this wire in two different modules. But I am afraid the voltage is too low if I do that.

Please see attached my error.

Thank you

[MarieV]

Thank you Dennis_Knutson,

I know I can add channels in the DAQ Assistant, but it is not the same kind od DAQ assistant (one is Angular Position and the other one is Frequency), or maybe there is something I don't know about configurating the DAQ assistant...

Thank you for your help

[Dennis_Knutson]

I thought that since they were both counter tasks, you could select two different ones. I can't test it myself right now.

[crossrulz]

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@MarieV wrote:

I know I get the error because I am using at the same time PFI 5 for the angle measurement and for the frequency. Maybe I can split the wire of channel I (I mean physically), and use this wire in two different modules. But I am afraid the voltage is too low if I do that.

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If you are worried about voltage drop, add a buffer circuit.  With simple buffer, you can easily supply two digital inputs.