DLPNIRNANOEVM: DLP NIRScan Nano EVM calibration

Hello Lukas,

Could you show what the measured chemicals look like?

Thanks,
Kyle

In the pictures above the measured compound is urea (prior and after new calibration) but with caffeine the difference is much more visible.

The absorption is negative after calibration:

The calibration is still a little bit strange. I've calibrated the device again with an 99% reflectance standard and measured all other standards again using 'factory' as reference in the scan tab.

If I click on the 'Scan Reference Select -> new' radio button and scan the 99% reflectance standard as new reference (like before in the utilities tab), I get the following results:

The 80% standard is too high and the 50% is too low.

I've also measured cellulose with both 'factory' and 'previous reference' and the reflectance is larger than 1 (= 100%) which leads to negative absorption values.

Hi Lukas,

The lamp ( light output) performance changes with time and environment factors like temperature/humidity etc.   It is recommend to periodically take a new reference or over-write factory  reference (using scan in the utility tab of GUI).

When you are comparing the absorption with factory reference with a new reference taken, they could be difference. The factory reference is comparing the reflected light with captured values of lamp at factory (condition & time). The new reference is comparison the reflected light with recently taken reference scan in your lab,

Typically both curve will have same shape as you mentioned and levels may be shifted.

Could you please save few scan in CVS file with details and upload? This will help us analyze and provide specific response to your case.

regards,

Vivek

Vivek Thakur said:

Hi Lukas,

The lamp ( light output) performance changes with time and environment factors like temperature/humidity etc.   It is recommend to periodically take a new reference or over-write factory  reference (using scan in the utility tab of GUI).

Yes, that's the reason why we did the calibration.

Vivek Thakur said:

When you are comparing the absorption with factory reference with a new reference taken, they could be difference. The factory reference is comparing the reflected light with captured values of lamp at factory (condition & time). The new reference is comparison the reflected light with recently taken reference scan in your lab,

Typically both curve will have same shape as you mentioned and levels may be shifted.

A shift in the absorption would be normal but negative absorptions (or reflectance > 1) in the whole spectrum is a little bit strange. The factory reference is not the original factory reference anymore.

I did the following steps (in < 1 minute):

• calibration with spectralon in utilities tab (overwriting the factory reference)
• measured a sample
• measured a new reference with the same spectralon standard used for calibration
• measured the sample again

data.zip

Hi Lucas,

Thank you for your patience.  I reviewed the CSV files. I assume that files with name scan_xx.csv were scan of the spectralon standards using "previous" radio button  in GUI and before taking these scans you used 99% standard using "New" radio button.

Similarity,the files with name scan_ref_xx were scan of  spectralon standards using "Factory"radio button in the GUI and before taking these scans you overwrote factory scan using "utilities tab" and scan.

Please let me know if my assumption is not correct.

Scan of standard suggest that EVM and firmware is working correctly and they are consistent between two methods of measurement.

However, actual values of scan data for sample is higher than reference.  It suggest that setup or configuration between scan of standards and sample has changed. If it was a problem with EVM or firmware, we should see same behavior for standard scan..

Could you please upload the screen shots of  GUI for couple of stand scan and sample. It is also possible to take a picture of how you are scanning sample?

regards,

Vivek