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NI PXI 6251 strange behaviour

Hi,

I have couple of questiobns about NI PXI 6251 in PXI-1045(with pxi-8360 Mxi-express controller).

First it works with some huge delays when Daq_mx_stop is called or even the vi is stopped by RED button

Second The reference trigger is not working for me...

 

When the simple start trigger is set anf APFI0 is used everythzing works fine (except previously described lond delay)

But if I set reference trigger it do not react on the triger pulse.

 

thanks in advance

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Message 1 of 11
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Hello YuriyPodoba,

 

can you please post your code and explain it for me a little bit deeper what exactly happend.

 

For your information about the delay, when using analog trigger

Unexpected Delay When Using DAQmx Analog Start Trigger

 

Addtional:

When you use an Analog Reference or Pause Trigger, and the analog channel is the source of the trigger, there can be only one channel in the channel list. If you have more than one channel for Pause or Reference Triggers, you must use APFI 0 or APFI 1.

 

M-Series Manual page 83

When you use an analog reference trigger source, the acquisition stops on the

first rising edge of the Analog Comparison Event signal.

 

Hope it helps, if not please let me know.

 

best regards
Alexander
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Message 2 of 11
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Hi,

 

Unfortunately the problem is not solved.

This behaviour is observed not only in my .vi but also in NI MAX when I create a task there.

 

    If I use start trigger option acqusition works with external trigger, but DAQ-assistent shows me a warning: 200010 (not all points are acquired or generetaed )

Long delay before the task finishing occures here as well.

 

    If I try to config reference trigger for the same input (APFI0) with the same parmeters it also reacts on a trigger but no data is read and DAQ-assistent shows me an error: -200281.

Also a long (~15sec) delay is observed before the task in NI MAX is finished comletely.

 

In attachment I've add an example where I have all these troubles but it is nothing else as very basic read example I have the same problems also in standart example from NI library.

 

Thanks in advance.

 

 

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Message 3 of 11
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sorry some correction in the case of reference trigger system do not reacts on trigger at all ... it looks that the task is finished by timeout.

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Message 4 of 11
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Hello YuriyPodoba,

 

i run your test vi with reference and normal trigger with a simulated device and no error is happend.

The configuration and settings seems to be possible. Can you please check, if

the external trigger or the APF1 trigger happend so the daq device can react on it.

 

Thanks.

best regards
Alexander
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Message 5 of 11
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as I've sad when i use start analog edge trigger (not reference) the system reacts and aquire the data as it should so I conclude that the trigger singnal is ok (it is also good on oscilloscope).

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Hello YuriyPodoba,

 

i tested your programm with real hardware and it works. Could it be that the card is demaged?

 

I used the 5V from the device (Pin 96) to trigger the APFI0 on PIN 29.

Can you plesae try this way to generate the trigger?

 

How will be your external trigger generated?

best regards
Alexander
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Message 7 of 11
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the card is new, the trigger is generated by external signal generator and is also +5v it is checked with oscilloscope.

Which device you have used? I have PXI-6251 card in PXI-1045 Chassis- in documentation it has no pin with number 96 the maximum pin number is 68.

But nevertheless I've used tested external trigger generator which is working with all other Ni cards we have.

 

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Message 8 of 11
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Hello YuriyPodoba,

 

sorry for the missunderstandings i tested with the USB-6251.

On your dervice is Pin 8 or 14 for the 5V and Pin 20 for the APFI0.

 

best regards
Alexander
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Message 9 of 11
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Unfortunately it not helps.

Can the reason be in Hardware compatibility?

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Message 10 of 11
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