EVM430-FR6043: Absolute TOF drops to 0 in high wind. But ADC Captured waveform seems OK

ramon navarro

Part Number: EVM430-FR6043

Hi experts,

I'm testing the EVM430-FR6043 in a wind tunnel with 200 kHz transducers. Everything works fine until it reach high wind speeds (around 100 km/h, and above). At this point th Absolute TOF measurements drop to 0 (and also the Delta ToF). But the ADC Capture waverform at this point seems to be OK. I tried different "GUI Based Gain Control dB", to increase or decrease the captured waveform and don't observe any improvement.

Figure 1. Increasing wind speed until 100 km/h. Decreasing wind speed after some time at 100 km/h:

Figure 2. Typical ADC Capture waverform al 100 km/h. Different "GUI Based Gain Control dB" modify the amplitud, but the Absolute TOF measurements remains at 0.

Figure 3. Basic configuration of the EVM.

Figure 4. Advanced parameters of the EVM.

What could be causing the measurements to drop to 0? Recommendations to improved that?

Best regards,

over 1 year ago

0 Sal Ye over 1 year ago

TI__Mastermind 25005 points

Hi ramon,

I think there might be some variables out of the limitation.

I am not the expert of the USS usage. And I will forward the thread to the relevant expert and ask his suggestion.

B.R.

Sal

0 Cash Hao11 over 1 year ago

TI__Mastermind 46765 points

Hi,

Any errors reported when the absTOF is 0?

Could you also send out the ADC "continuous capture" data, half minute ADC capture data should be fine when the absTOF is at 0.

Best regards,

Cash Hao

0 ramon navarro over 1 year ago in reply to Cash Hao11

Prodigy 130 points

Hi,

I see the following errors during the test. I am not sure those errors are related with the previuous question. I think they come from some code I added to the example at the end of the function, before the sleep (and the gap parameter is set at 100ms in my example). ToF measurements are OK at moderate wind speed, althoug I see the same error messages randomnly.

I will send the ADC "continuous capture" as soon as possible (less than 2 days).

Regards,

0 Cash Hao11 over 1 year ago in reply to ramon navarro

TI__Mastermind 46765 points

Hi,

Okay, you can try longer the UPS0 to UPS1 gap to like 500ms to avoid this error. Wait for your data.

Best regards,

Cash Hao

0 ramon navarro over 1 year ago in reply to Cash Hao11

Prodigy 130 points

Hi Cash,

Please find attached the ADC "continuous capture" at 100 km/h wind speed aprox. The UPS0 to UPS1 gap is set at 200ms.

As in previous tests, the typical ADC Capture waverform looks OK to me, although the algorithm is unable to measure the ToFs.

cont-capture-10_35.csv

I also tried a second setup with less distance between transducers. It looks OK even at 120 km/h:

My guess is that there is some overflow in some variable that causes the algoritm to fail and report '0s' in every ToF related variable. But I am not able to review the source code, it is pre-compiled.

Regards,

0 Cash Hao11 over 1 year ago in reply to ramon navarro

TI__Mastermind 46765 points

Hi,

I make the below changes in the USS_userConfig.h. You can generate the head files with USS design center. And then manually change these parameters. They build the project with this new configuration.

#define USS_ALG_ABS_TOF_SEARCH_RANGE 20

#define USS_ALG_MAX_SAMPLE_SHIFT 100

Best regards,

Cash Hao

0 ramon navarro over 1 year ago in reply to Cash Hao11

Prodigy 130 points

Hi Cash,

Now it is working fine!

ToF measurements at around 120 km/h:

Regards,

+1 Cash Hao11 over 1 year ago in reply to ramon navarro

TI__Mastermind 46765 points

Good to know. I am going to close this thread.

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EVM430-FR6043: Absolute TOF drops to 0 in high wind. But ADC Captured waveform seems OK