Closed JochiSt closed 1 year ago
Software / Firmware:
PCB changes: (only population)
There is a problem with reading back the gain settings see #21.
This problem has been solved.
I've implemented sending out the measured and calculated temperatures.
These are the values, the PID is working on. It seems, that this needs a bit of tuning to get the best results. Especially in the region, where two different gain settings are used, the behavior can be better.
A current calibration in order to determine the real gain of the amplifier seems a good next step.
The pink curve is the internal used temperature, the wiggles at about 100s might be a problem for the PID controller.
The gain setting resistors listed in https://github.com/JochiSt/OpenFlowMeter/issues/20#issue-1516488905 are by a factor of 10 to large.
Those values cause might cause the amplifier to cause strange effects in the unity gain setting. (see https://github.com/JochiSt/OpenFlowMeter/issues/22#issue-1518569229)
This problematic was solved in https://github.com/JochiSt/OpenFlowMeter/issues/22#issuecomment-1371897907.
The correct gain setting resistors are (Ch0):
And same for Ch 1.
From the HG
to the LG
of the current section, there is some slight mismatch, which causes the temperature to be negative. (Means, that a too high current is measured)
The gain switching is working. Although it needs some improvements. (There is always room to improve things)
In #18 a optimised gain setting has been found, which needs to be implemented in hardware (exchange of resistors) and software (configuration values).
The results from #18 are: U channel:
I channel: