EV_MOD_CH101-01-02 invalid measurement

[erian747]

We have successfully used a EV_MOD_CH101-03-01 which 180 degrees opening to measure distance, range configured to 1200mm

With the exact same software and configuration we have tried the EV_MOD_CH101-01-02 which have a 45 degrees opening

For some reason it seems to be stuck reporting 139mm, regardless of surroundings and how it is mounted (laying in open air or its opening sticking out of a hole in a large plate)

Could there something we are missing in our configuration that causes this?

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Notify: @tdk-invn-oss/ultrasonic-maintainers

[gjabouley-invn]

@pbesson-invn @rprzybyla-invn @mhkline did you get notified of this issue?
Seems the notification mechanism of GitHub is not always working fine...

[mhkline]

Notifications are very hit or miss for me. I don't think I got one for this, but I was also out of office when it came.

Hi @erian747,

Generally, this kind of problem is due to either a real object within or near the sensor's FoV or due to the sensor tripping on the decay of its own transmit signal.

The FoV of acoustic horns is not like a cliff. We specify the full-width half maximum. So, at 45 degrees off axis, the returning signal would be half as strong as it is directly on axis for a 45 degree horn.

The best way to debug these issues is to use the ICU-x0201 EVK software and view the A-scan and fish-finder plots. You'll be able to see where the signal is unexpectedly strong and then adjust the threshold to ignore it. Another option is to use the static-target-rejection feature (STR), which is available from the EVK Configure Sensor widget. In this mode, targets that do not change in amplitude over time are gradually filtered out.

Edit:

Sorry, I responded as if you were using the ICU parts, but you're using CH. You can still try the static target rejection, and you can use the SonicLink GUI to view the raw data if you have a SmartSonic board.