tare at startup

[ilker-aktuna]

I have a weird issue.

If at startup, I do tare like:
LoadCell.start(stabilizingtime, true);

it works fine. But it does tare when the device reboots (due to electricity outage)
I don't want to do tare at startup.
So I change it to:
LoadCell.start(stabilizingtime, false);

But when I do not do tare, it does not measure correct after a reboot.

I read the saved calibration value from eprom and set it as calibration value at startup:

startup code:

 EEPROM.get(calVal_eepromAdress, calval);
  if(!(calval>0)) {
    calval=1.0;
  }
LoadCell.start(stabilizingtime, _tare);
  if (LoadCell.getTareTimeoutFlag() || LoadCell.getSignalTimeoutFlag()) {
    Serial.println("Timeout, check MCU>HX711 wiring and pin designations");
    while (1);
  }
  else {
    LoadCell.setCalFactor(calval);
  }
  while (!LoadCell.update());
  LoadCell.setCalFactor(calval);

If I manually do a tare after reboot, it starts showing the correct value. So it surely saves calibration value and loads at startup.
It just does not preserve tare at reboot.
what is wrong with my code ?

[olkal]

Hi!
You need to save the zero-offset (tare) value and restore it at reboot. See the example Persistent_zero_offset.ino.

[ilker-aktuna]

ok. I didn't know that.
Do you have a documentation of this ?
Examples are fine but from their name sometimes what it does is not understood.

[olkal]

No, unfortunately not. But I have now added a line in the readme file for this particular issue.

[ilker-aktuna]

thanks. that's better than nothing :)
btw, I have another question:
when there is a change of load, the getData() method does not provide the final measurement at one shot.
I have to call it several times to get a good measurement.
So when there is a demand for measurement, I implemented like this:

                for(int x=0;x<30;x++) {
                  boolean _resume = false;
                  while (_resume == false) {
                  if (LoadCell.update()) {
                    i = LoadCell.getData();
                    _resume = true;
                  }
                  }
                }
               finalWeight=i;

is this correct implementation?

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