• TI Thinks Resolved

DLPNIRNANOEVM: Reducing measurement time / system integration

Prodigy 100 points

Replies: 9

Views: 184

Part Number: DLPNIRNANOEVM

Hello,

First of all thanks to Hirak who helped me a lot to get my Nirscan Nano running under C#. Meanwhile the software works fine.

1. My next task is to reduce the measurement time. First tests showed that I have to average at least 3 scans to get a reliable result. I switch on the lamps pemanently to reduce the warm up time. Now the estimated scan time is 0.75 s, the actual scan time is about 1.0 s. Do you know why the two values differ? I would lime to reach about 0.6s. Are there any more possibilities to reduce the measurement time? As far as I know, the number of scans can be reduced, the lamps can be left on permanetly and the prescan can be omitted. Do you have any more ideas?

2. I have to integrate the device into an existing process. As the space is limited, I should place the sensor in a certain distance to the measuring position. I think I should use an optical fibre to reach the measuring position. Could you recommend a product or a manufacturer of such a fibre which is propriate for the Nirscan?

Thanks & Regards,

Simon

  • Hello Simon,

    Please let us look into this and we will get back to you.

    Thanks,

    Kyle 

  • In reply to Kyle Rakos:

    Hi Simon, 

    Kindly give us some more time to look at this, will be back soon!

    Thanks & Regards,

    Hirak.

  • In reply to Hirak Biswas:

    Hi Simon, 
    We have started to look into your query, expect a reply soon!

    Thanks & Regards,

    Hirak.

  • In reply to Hirak Biswas:

    Hi Simon, 

    Thanks for your patience!

    You have option to trade off Spectral range, Digital Resolution and Number of scans to improve the scan speed. But be aware, depending on the nature of application trading off one or more of them may not be practical. You have to decide your required spectral range, resolution etc and then optimize between these factors and scan time.

    As for the optical cable, I we are contacting the design team to get more info on this one. Kindly stay tuned!


    Thanks & Regards,

    Hirak.

  • In reply to Hirak Biswas:

    Hi Hirak,

    thanks again for your support! I followed your advice and tried to reduce the required scan time to a minimum. This works fine so far. I was able to reach about 300ms.

    Now I have one more question: Having done the scan, it takes about 200ms-300ms to transfer the data from the sensor to the PC via USB. Is this normal or am I doing something wrong? I checked my whole project but I couldn't find any suspicious code which could provoke a loss of time.

    Could you meanwhile get some information concerning the optical cable?

    Thanks & Regards,

    Simon 

  • In reply to Simon Ilgenfritz:

    Hi Simon, 

    Kindly give us a bit more time, we will get back on your queries soon!

    Thanks & Regards,

    Hirak.

  • Hi Simon,

    For #2, we have had luck with this type of fiber which has a round to linear fiber bundle to maximize coupling efficiency between the sampling location and the input to the slit:

    https://www.thorlabs.com/thorproduct.cfm?partnumber=BFL200LS02

    Note that it will be important to design your optics at the measuring position to maximize received signal. This will be especially important because of your desire to minimize scan time.

  • In reply to Eric Pruett:

    Hi Eric,

    thanks a lot for this information! I will try out this fiber bundle and inform you about the results. Currently, I achieve an overall measurement time of 0,6s. Hopefully this will also be possible using the fiber bundle...

    Shall the linear end of the bundle point to the sensor or to the sample? When I look through the saphire glass at the sensor, it seems to be round. Is it a line sensor? This would be important for my further design condiderations.

    Thanks & Regards,

    Simon

  • In reply to Simon Ilgenfritz:

    Hi Simon,

    The optical entrance to the NIRscan Nano design is a slit. This slit is then dispersed (wavelengths are separated) and focussed onto the DMD. The reason this type of fiber can provide better coupling efficiency is that the linear part can efficiently fill the slit, while the round portion often couples better to collection optics at the sample side.

    Note that the EVM comes with a reflectance sampling head which includes lamps to illuminate the sample and then lenses to refocus the reflection from the sample onto the slit. You will need some way to mount the fiber onto the light engine and focus the end of the fiber onto the physical slit. You will find a design we did for such a model on the reference design page, under "Design Files -> TIDA-00554 Fiber Input Illumination Module":

    http://www.ti.com/tool/TIDA-00554

    There are also third party input modules or full spectrometer light engines which come with a fiber input.