What is the order of ph calibration? pH, after slot 1 calibration, put the probe in the 4.0 buffer and wait for it to drop to 4.0 Should I press the “Calibrate pH, slot 2” button? Or wait two minutes Should I press the “Calibrate pH, slot 2” button?
If you’re referring to the ADS1115 or ADS1256 Generic Analog pH/EC Inputs, the order or solution values does not matter, they only need to be different. So, you can use 4 pH slot 1 and 7 pH slot 2, or 4 pH slot 1 and 10 pH slot 2, or 7 pH slot 1 and 4 pH slot 2, etc.
Do I have to put it in 4.0 solution after measuring 7.0 and wait until it drops to 4.0 before pressing the button?
It does not have a slope before it’s calibrated, so you will not likely see it change to 4 when you put it in a pH 4 solution. Only after it’s calibrated will it return 4 in the 4 pH solution. After putting it in any of the calibration solutions, all you can do is wait for the measurement to stabilize before storing the calibration value.
Put it in 7 solution, press the Calibrate pH, slot 1 button, and take it out after 5 minutes
and
put it in 4 solution, press the Calibrate pH, slot 2 button, and take it out after 5 minutes?
At least 2 minutes is sufficient to stabilize, but different probes may take different times. You should monitor the output value to determine when it’s stabilized.