Strain gauge load cell tests in a DIY climate chamber

Ich teste gerade 2 x FiPy in meinem Gewächshaus. FiPy1 mit China-Wägezelle (links) und FiPy2 mit Bosche H40A (rechts).


Daten vom FiPy1: t_i_5 wurde von der Sonne beschienen

Daten vom FiPy2: t_o liegt im Schatten direkt an der H40A

Die Temperaturkompensation der Bosche H40A ist ersichtlich.

Very interesting, thanks much !
May I ask you what was your test setting in term of measure taking ? More precisely, did you reset the offset of the load cell each time you took a measure (seems to be the normal way of operating with any scale that is not permanently loaded) or did you establish the offset once for all and took all your measures with this same offset (when the scale is always loaded, it’s impossible to reset the offset at each measure) ?

Ah - I misunderstood. I thought you were talking generally about measuring. If you have a calibrated scale its of course different. Then the amount of preliminary measurement necessary is inverse proportional to the trust you put into the datasheet of the manufacturer. :slight_smile:

Hello Henri, nice to have you at hiveeyes on board! Welcome! You may have seen this thread with a “nice” collection of the same experiences. Feel free to add details the audience may not know yet!

Good explaind! So in terms of scale calibration factors we have in our code e.g.

const long loadCellZeroOffset = -80186;
const long loadCellKgDivider  = -21738;

and the variable loadCellZeroOffset is the bad guy in our game!

One of the most interesting parts in this thread is:

@zmaier used the same settings, the same model of the load cell (“the good one”) and still temperatur effects! And the effect ist different for differen individual load cells. So not the model is the reference for an compensation factor but each cell. That makes building mass hive scales not easy, you have to test and set the compensation factor for every single cell.

My conclusion would be, take a not sooo sensitve load cell and forget about compensating the temperature.

Thanks much Clemens, I appreciate the help and the guidance.

In your experience is the firmness of the frame supporting the load cell an important factor for the measure accuracy ? I am still waiting for the hopefully final double H frame and I am questioning a little bit the frame I am using for testing.