JochiSt/OpenFlowMeter

Calibration using 100Ohm

Opened this issue · 2 comments

JochiSt commented

I tested the OFM using two 100 Ohm resistors and a DAC sweep. (From the calibration, it is known, that 32 LSB DAC are about 1mA measurement current)

Channel 0

measurement_20220309_065823_CH0_1023

Channel 1

measurement_20220309_065823_CH1_1023

Overall it seems, that there is a bit to much noise for the low voltages (and currents). This needs further investigations, whether there is some room for improvements.

JochiSt commented

Added 100nF at the position of D5 and D6.

JochiSt commented

Since this effects only channel 0, the results DAC sweep looks more smooth.

measurement_20220311_081058_CH0_1023

And the precision has also increased. Maybe further capacitors are needed to stabilise the measurement circuit.