Hi,
I thought it’s more appropriate to answer here.
I’ve done the experiment.
With EC probe inside the solution i have no chanche to measure PH, sooner or later it stabilizes to 2.14V for any ph value.
What I could observe is that the ph meter i use as a reference was not affected by this interference and measures correctly.
Powering up EC sensor, it connects the power supply output to the water.
Connecting the GND of raspberry with a wire inside the water i obtain the same effect.
With two separate power supply i don’t have interferences.
I solved this with your method, using two 1uF capacitors for both wires of the probe.
1 uF fit perfects, i have same voltage on the output.
Thank you!
My question is why producer lost the capacitors or at least warned on the manual?
I prepared different solutions for EC and PH using my EC and PH tester as reference.
I put the points in a program called graph, that found the equations.
I edit it a bit for have same measurements of my reference tester.
Trying to edit your script is too difficult at the moment, so i will use regular ADS1115.
I thought i don’t need temperature compensation, because tha variation is minimal.
For re-calibration i don’t know, at the moment the probes are still calibrated.
I think it will be enough to calibrate for a single value and translate the function curve.
But i’have a strange effect:
I’ve just EC1,4 PH4 PH7 calibration solutions, i got the others by adding ph- or fertilizer for EC.
With EC calibration solution i don’t have same voltage with water and fertilizer with same EC, difference about 0,2v.
But both EC measure the same value in my reference tester.
Tried many times.
So i can’t use the calibration solution to calibrate.
I need to check in the long time if it works properly.
If you have any other suggestions let me know.
