External and onboard sampling in parallel

Question

Hello everybody,
I made a simple example to demonstrate what I am trying to achieve but my problem can be summarized with one question: Is it possible to have in parallel one task that samples channel AI0 with the onboard clock and another task that samples channel AI1 with external clock source?
In my application I have 
1) One task measuring lets say pressure or temperature at one channel with the onboard clock
2) One task calculating the frequency of revolutions of incremental sensor (IRC)
3) One task sampling signal from laser probes using the IRC signal as external source
They are supposed to run in parallel
2+3 works perfect but when I add also 1 I get Error -50103 occurred at DAQmx Start Task.vi:1, The specified resource is reserved. The operation could not be completed as specified. Also 1+2 works perfect together. Program attached - it's just fast example.
Thanks a lot
Message Edited by ceties on 07-07-2009 08:26 AM
LV 2011, Win7
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Attachments:
Rpm_AIIntClk_TriggerExtClkAcq.vi ‏82 KB

Answer 1

Trying to create more than one task for AI the same time result in the encountered error message....This is because AI can only have a single sample clock source. Due to device access, this is a prerequisite for a single device. Having more than one DAQ device will enable you to define two different clocks for the two devices.
hope this helps, 
Norbert 
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