Generate continuous samples with ni 6229

[Emraisel]

Hello,

I need to generate continuous digital output samples with ni 6629. However it gives Error 200303 occured at DAQ Asistant; possible reason: External sample clock source must be specified for this application. I could not observe any output on the oscilloscope.

Could you please tell me about what should I do to generate? How can I arrange sample clock rate with details?

Thanks ver much in advance..

Regards,

ERS

[Emraisel]

I forgot to tell you that I am using Labview Signalexpress to generate signals..

[Emraisel]

Is there anyone to help me? Please!!!! Help.!!!

[Jas.W]

Hi Emraisel,

This error will occur when you do not specify a clock for your digital IO. M series cards cannot use the internal clock for DIO, but you can use an external source as a clock. The following KnowledgeBase article will provide you with the different options available.

http://digital.ni.com/public.nsf/allkb/51754212AD10BDCE862573BD007BFDD2

Let me know if you have any further questions regarding this.

Kind Regards,

Jas.W 

[Emraisel]

Hello Jason,

Thank you very much for your replying. 

I had tried the these ways.

i) Use one of the onboard counters to generate a sample clock for your task.

ii)Use an external sample clock for your task

I am using Labview SignalExpress and for the first way I think for that mode to create counter output task is not possible on signalexpress. If there is a way to create counter task on signal express, please let me know.

For the second way, what kind of device do I need to connect PFI to adjust the external sample clock?

Thanks again,

Regards,

Selcuk

[Jas.W]

Hi Selcuk,

It is possible to create a counter task in SignalExpress. To do this you Add Step > Generate Signals > DAQmx Generate > Counter Output > Pulse Output. Select your device from the list, then set up the timing etc. Set Generation Mode to Continuous if you want it to create continuous pulses. It should also tell you which PFI line it will output this signal to. Feed that output into another PFI line, then set up you digital task as you have done in the past. When on the Advanced Timing tab (only available once Generation Mode is not on 1 Sample), select External for the Sample Clock Type, then choose the PFI line that is the counter is connected to. Try that out and let me know how you get on. 

Kind Regards,

Jas.W 

[Emraisel]

Hello Jason,

Thank you for your helping.

I have prepared the structure as you described. Firstly, I put the counter pulse output which is output is ctr_0, its output terminal is PFI 12, then create digital signal and finally generate digital output, respectively. I connected the oscilloscope to the PFI12/P2.4 line in NI USB-6229 Box. At the USB-6229 pinout scheme PFI12 and P2.4 are the same. For the generate digital output the advanced timing, I adjusted external option for sample clock type and clock source is PFI12.

I can observe digital continuous outputs on the oscilloscope but it gives an error which is;

Error -201062 occurred at DAQ Assistant

Possible Reason(s):

Measurements: Selected lines do not support buffered operations.

Ensure only lines that support buffered operations are being used in the task. If using change detection, the task must be changed to non-buffered hardware timed single point to support these lines.

Device: Dev2
Physical Channel: port2/line4.

So that I changed the digital output port from p2.4 to P0.0 then tried again but this time I could not observe any sıgnals and it gives another error which is

Error -200463 occurred at DAQ Assistant



Possible Reason(s):

Measurements: Specified read or write operation failed, because the number of lines in the data for a channel does not match the number of lines in the channel.

If you are using the Digital Waveform datatype, make sure the number of lines in the digital waveform matches the number of lines in the channel. If you are using boolean data, make sure the array dimension for lines in the data matches the number of lines in the channel.

Number of Lines in Channel: 1
Number of Lines in Data: 16

Please could you help me what is wrong?

Thank you,

Kind Regards,

Selcuk

[Jas.W]

Hi Selcuk,

When doing continuous digital outputs you will have to use port0 as this is the only port that has a buffer, which is why the first error no longer occurred when you switched to port 0. 

The second error message that you received seems to be because you are trying to output 16 lines of data from a channel that only supports a single line. Check the data you are writing to the output and ensure it is only a single line of data.

Also check your wiring and setup. It sounds like your current configuration isn't quite right. the configuration should be;

Output counter on PFI12,

Wire PFI12 into a different PFI line, PFI1 for example,

Select PFI1 as the clock source on your digital output task.

Ensure the data you are writing to the output is correct. Let me know if you have any other questions.

Kind Regards,

Jas.W 

[Emraisel]

Hi Jason,

I tried as u described. I can observe the digital pulses succesfully on the oscillascope but after sometime it gives an error again which is;

Error -200292 occurred at DAQ Assistant



Possible Reason(s):

Measurements: Some or all of the samples to write could not be written to the buffer yet. More space will free up as samples currently in the buffer are generated.

To wait for more space to become available, use a longer write timeout. To make the space available sooner, increase the sample rate.

Property: RelativeTo
Corresponding Value: Current Write Position
Property: Offset
Corresponding Value: 0

I adjusted the reading value from 100 to 1 but nothing changed.

Please help again.

And is it possible to generate two or more digital continues pulses from different pinouts?

Thanks very much!

Best Regards,

Selcuk

[Jas.W]

Hi Selcuk, 

This error can be fixed by adjusting the timeout, found in the Advanced Timing Tab as it appears it is timing out. 

As for more continuous digital outputs, you would only be able to output from Port0 as this is the only port that is buffered (so P0.0...P0.7).

Let me know if you have any more questions.

Kind Regards,

Jas.W