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EVM430-FR6047: Having trouble with the calibration process

Anthony Davidson
Prodigy 90 points
Part Number: EVM430-FR6047

Tool/software:

I am using the EVM with the Audiowell DN25 inline pipe. I have a reference water meter that is measuring 1.101 cubic meters in 10 minutes, which is 6,606 L/h. Using the default values in the GUI, the Waveform graphs for Volume Flow Rate was measuring about 1800 L/h. Since this was low I tried the calibration process.

I tried to follow the calibrations steps located here.

The first issue I have is that there are no units for the expected volume flow rate in the Meter constant calibration section. Just to try it out, I used 50 for expected VFR and ran water through my pipes for 2 minutes and followed the procedure in the link. When the calibration was over I entered 49.5 for the actual VFR, as in the example, but the warning message that I got didn't change the Meter Constant number as in the example.

So then I just entered the new value from the example, 11771796.95, in the Meter Constant in the GUI. Re-running my sustem measured a Volume Flow Rate than 1800 L/h. Then I entered 2000000 for the Meter Constant and ran my system again, but now the measured Volume Flow Rate was around 200 L/h. Further, now anytime I enter any number for the Meter Constant the measured Volume Flow Rate is always around 200 L/h.

Is there a bug in the GUI or in the firmware that runs on the MSP430?

What are the units in the calibration for Expected and Actual Volume Flow Rate?

When I follow the calibration process, does the EVM actually take any measurements or do I just need the actual VFR as measured by the reference meter?

  • 0
    Prodigy 90 points

    I found one of my problems. When I was manually entering MEter Constants, I was missing a digit. So 2,000,000 should have been 20,000,000.

  • 0
    TI__Mastermind 31865 points

    Hi,

    Usually, you can consider the units is LPH in Expected and Actual Volume Flow Rate. 

    And in calibration process, you do need a reference meter to tell the EVM board of your expected VFR. 

    Which guide are you following? Could you share the link of it?

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Prodigy 90 points

    Apologies. I included a link to the calibration guide I was using but it didn't seem to work. I'm not sure where the actual User Guide is, but the link is to a fil called ch_calibration.html that was installed on my hard drive when I installed the GUI.

    I took a guess that the VFR units was in L/h. But my point is that the calibration process doesn't seem to be working on my computer.

    My reference meter measures a VFR of 4500 L/h.

    I go to the main Calibration tab in the GUI:   (it's greyed out right now because my target is not connected). I enter 4500 in the Expected VFR field, run the water in my pipe system, and click Start Calibration. I run the calibration for 1 minute as suggested in the USer Guide, then click Stop Calibration and this window pops up:

    Note that in the window above the Mean VFR is 0. This should be a number calculated by the target or the GUI, right?

    Anyway, I enter the actual VFR of 4495 and click OK, and this window pops up:

    Note that the Meter Constant hasn't change so I don't think the calibration process worked. Is this a bug or am i doing something wrong?

    On a related note, the default Meter Constant in the Configuration tab was 12742000. I can manually change this number to make the target measure a VFR close to what my reference meter is measuring. That's why the Meter Constant in the above calibration window is 47550000. I arrived at this number by manually changing one digit at a time in the Meter Constant. But this is not the proper calibration process.

    Again, does the calibration process have a bug or am I missing something?

  • 0 in reply to Anthony Davidson
    TI__Mastermind 31865 points

    Hi,

    Anthony Davidson said:
    Note that in the window above the Mean VFR is 0. This should be a number calculated by the target or the GUI, right?

    Something goes wrong at this step. The mean VFR should not be 0 when you running a flow in the pipe. 

    What is the waveform page look like when you running a flow in your pipe. 

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Prodigy 90 points

    Apologies for not actually stating that when I performed the calibration step I had water running through the pipe. But yeah, I had water running through the pipe for which the calibration step reported VFR = 0.

    The plots below are all captured with the Audiowell DN25 inline pipe.

    My waveforms look like textbook cases of awesome.

    Here is the ADC capture for zero water flow: 

    And here are the waveforms for 1260 L/h VFR according to my reference meter. The VFR shown in the plot is off because I can't perform the calibration. 

    So again I ask if there is a bug in the GUI or if I have missed configuring something.

  • 0 in reply to Anthony Davidson
    TI__Mastermind 31865 points

    Hi,

    I do not think there is any bug in the GUI. So, I recorded a video about how to calibrate the meter constant value. Please check what is different with yours.

    Best regards,

    Cash Hao

  • 0 in reply to Cash Hao11
    Prodigy 90 points

    Thanks for the video.

    Apparently, there isn't a bug in the GUI, but there IS a bug in the explanation of how to run the calibration process. It appears that the calibration process only works if data is being captured in the Waveforms tab. In other words, one has to click Start in the Waveforms tab, and then run the calibration.

    Does it say that somewhere in the guide? That you have be capturing data in the Waveforms tab before doing the calibration? If it does, I completed missed that.

    It was your video that suggested that I should try that.

    My issue is now resolved.

  • 0 in reply to Anthony Davidson
    TI__Mastermind 31865 points

    Hi,

    Good to know you solved the issue. 

    I do not realized that you need to start the waveform first then run the calibration before. Thanks for sharing it out!

    Best regards,

    Cash Hao

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