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inconsistent time interval in plw files recorded by adc11

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inconsistent time interval in plw files recorded by adc11

Postby WILL » Fri Mar 11, 2005 5:11 pm

hi,

I was trying to take voltage samplings(1000 or more) at 1ms interval with adc11(parallel port) in one channel. The setting was real time continuous and non repeatable. The time colume from the plw output file came out to be 0,10,10,10,20,20,......ms rather than 0,1,2,3....ms. I have also tried for other samplings at 10ms and 100ms, but the time seems to be only working at 1s interval.

I don't know if this is the file format problem or the actual time recorded is wrong. So would it help if I convert the original plw file to text file. And could someone help me on the batch conversion software. Coz I need this ready for an experiment soon.


Thank You
WILL
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Postby Sarah » Mon Mar 14, 2005 9:45 am

Hi

Thank you for your post, I am sorry to hear that you have been seeing problems.

This problem is usually related to the fact that the ADC-11 uses the Windows clock and at high sampling speeds it is not always possible for it to sample and timestamp at the correct rate and it thus makes up for it by duplicating readings.

The way to get round this is to use our USB to Parallel adaptor as this would take over the clocking of it.

The problem could be just the timestamping is out though - I would recommend taking the readings into Excel and seeing if they still plot a smooth graph as in some cases we have found that the readings were taking at the correct time interval but were not correctly timestamped.

Hope this helps

Best Regards
Sarah
 

Postby WILL » Mon Mar 14, 2005 11:35 pm

hi

Thank you for your reply.
From my readings, they are not duplicating but systematically round up when they read the plw.

I wonder if i can directly have access of the plw value to convert them to a .txt or excel files without using cut and past (from the logger's software), i.e. using the reading of the file and a code.

Thank you
WILL
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Postby Sarah » Tue Mar 15, 2005 10:34 am

Hi

Thank you for your post.

You can save as text in the software by going to Save As and changing the file type. The other way to do this is to click on the write to disk button in the spreadsheet and you can then save it as a .prn or a .txt file.

Hope this helps

Best Regards
Sarah
 

Postby WILL » Tue Mar 15, 2005 3:36 pm

Hi,

Thank you for your reply.

I have tried the methods you suggested, but the time colume of the readings from the spreadsheet was all round up (like 0,10,10,10,20,20,20,20,30ms...rather than 0,1,2,3,4ms,...).
If I save this .plw file as .txt file, the time colume of the readings would be the same in the .txt file.

I think that the format of the data in the .plw file may be altered in the the spreadsheet.
So I want to convert the original .plw file directly into .txt file(uncode), which would give the correct time colume(0,1,2,3,4ms,...). Is there a possible way to do that.

Thank You
WILL
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Postby Sarah » Wed Mar 16, 2005 10:08 am

Hi

Thank you for your post.

Unfortunately I am not aware of any way of doing this, the only ways of saving to text that I am aware of are the ones I mentioned before.

Best Regards
Sarah
 


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