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time column got error with write to measurement file

Good evening everyone.

Our group is using write to measurement file to record our data. Our DAQ assistant set to 'N samples 10 samples to read 100Hz', cause if set to 'continuous sample' our vi will shut down after a few sec.

 

We are now facing a problem that our 'Time column' change to '1/1/1904 00:00:00' as shown in A12

data.jpg

Never do we get this kind of error...could anyone can help us with this??

 

Also the soc column and life cycle column, we don't know why they records data in this way...not like voltage and current column??

is it because the setting for DAQ assistant??

We are using NI 9227 and NI 9229 as our input.

 

Thank you all for your kindly help!!

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Message 1 of 5
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Could anyone help us wth this????

 

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Will you post either your vi or a screenshot of the block diagram? It is hard to say anything based on this excel screenshot.

Best regards,

CsabaF
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I think the poster has problem with this VI:

http://forums.ni.com/t5/LabVIEW/VI-continuous-send-output-voltage-after-press-stop-button/m-p/305242...

 

I think the problem is caused by the inconsistent dynamic data merging (maybe the size of the different dynamic data "wires" do not match?). You should avoid using dynamic data and Express VIs. Just check some examples (via the Help menu in LV) how to make proper DAQmx data logging and saving it to TDMS binary file.

This TDMS file type is very useful, since it is binary (fast read/write access) but you can also import to Excel quickly (free Excel plugin you can download).

 

Try to modify your VI in the while loop, and eliminate all the Express VIs as I recommended in your other post. If you get any problem during the change, post here your VI and we can help.

Also, please downconvert your VI which you attach to LV2012 version ("Save for previous version..."), so more people can open your VI (not everyone using the LV2014).

regards,

 

 

EDIT: yes, the problem is that, at every iterationin the while loop, you write 10 data points to your file via dynamic wire but the other dyamic data wires contain only one number.

I am not sure about the time stamp problem though...

 

edit2: what you can also try, only sample 1 data and not 10 per iteration in the DAQ Assistant, maybe this will help. If you still need 10 data points with 10 Hz speed, you could also calculate an average value of the 10 points per channel and use it. All depends on your application requirements...

But I really recommend you to stop using Express VIs, life is much easier without dynamic data...

You also do some data coercing, for example you connect your dynamic data wires (containing 10 data points) to numeric double indicators, which is not correct...

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I have never used the dynamic data type, somehow I managed to build all of my DAQ applications without that type. Your log seems to reset the timestamp after 10 samples, so I guess it has something to do with the DAQ settings.

 

I agree with Blokk, try to redesign your vi or try to explain what you want to do there. A simple battery charging test application can be done by simple state machine or in worst case a producer-consumer setup. 

Best regards,

CsabaF
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