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Original question:

EVM430-FR6047: EVM430-FR6047

EVM430-FR6047: ADC capture results

maroti shinde
Prodigy 40 points
Part Number: EVM430-FR6047


Hiii

 I'm getting some data on the USS GUI which I manipulated according to the USERGUIDE document named 'slau810b' & after that geeting the ADC & waves as follows in still water condition.

Can you please check wheather I am going in correct direction?

  • 0
    TI__Genius 16070 points

    Hi Maroti,

    It is a bit hard to make out the numbers in your DToF, AToF, an VFR graphs, so it is hard to comment on these. You may want to try uploading larger/higher resolution images so I can read them properly and comment.

    With that being said, based on your ADC capture, things look pretty good. That signal looks very much like our examples. Based on that, I would guess that you have utilized the data from your frequency sweep correctly. With this ADC capture I would also guess that your DToF is steady and close to zero in a zero flow drift test. Once you have done this test you can adjust the DToF offset in the device parameters window to center your moving average around 0.

    So if you want you can post better screenshots so I can read the numbers and be sure, but based on the other two images, and the fact that you are working along with the water meter quick start guide, you are doing quite well. I will add a link for another resource, that may be a bit repetitive, but is worth skimming through for additional information and guidance: The USS Academy. It gives more of a lesson-style walk through, rather than a how to guide, which you may find helpful. Also, once you get further into development using the USS library, you will find the USS Design Center Users Guide to be quite helpful.

  • 0 in reply to Dylan OBrien
    Prodigy 40 points

    Sorry for the previous images uploaded of low resolution ,please check the current images and suggest any changes if required.

    Problem statement:  In my current setup whenever i am measuring volume on the lcd of evm430fr6047 it is giving me wrong values.I am passing 10 litres of water but still it is showing 3 litres, i tried changing the rate parameter to 1000 in   g_ResultsOfLastMeasurement.last_volume +=resultsCalcVolume(0x3E8) code but still the problem persists.I tried everything and then checked the adc capture and other parameters .Please suggest any solution to this problem.

  • 0 in reply to maroti shinde
    TI__Genius 16070 points

    Hi Maroti,

    Thanks for the updated images. As I suspected, your ADC capture looks good and your dtof appears to fluctuate within the normal range. 

    As for your problem statement, have you tried changing your meter constant? This is the typical method our customers use to adjust the calculated volume flow rate. Considering that your zero flow drift test also shows a dtof of nearly zero, I think this is likely the only issue. As I mentioned previously, you should try setting your DTOF offset parameter to about 22 (20 to 25) so that the moving average of your DTOF actually centers around 0. This wouldn't cause the difference of 3 liters to 10, but it will make your flow reading slightly more accurate.

  • 0 in reply to Dylan OBrien
    Prodigy 40 points

    Hii Dylan,

    Thanks for the above solution. As mentioned by you i tried setting the  DTOF offset parameter to about 22 (20 to 25) following were the results that i got while testing.

     

    Problem statement: 1. My volume is still mismatched eg:10 litres passed showing 5.6 litres(PLease comment).

                                    2. how can i change meter constant ,and why it is so large in this case.Please explain how to calculate it and how you guys have                                                calculated.

                                    3.Please guide how i can improve the volume reading as it is highest priority in my application. 

  • 0 in reply to maroti shinde
    TI__Genius 16070 points

    The volume will become accurate once you have set the meter constant correctly. For information about this, please see page 7 / section 11 of the USS FAQ.

    Finally, in your new screenshots, were you expecting the jump in DToF and VFR? Due to that jump, the scale is quite large and it is hard to see how accurate the new DToF is. As a general rule, when you are performing zero flow testing, you want the DToF moving average near zero. This is done by adjusting the DToF offset.

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