I'm using a “pH Signal Conversion Board V2” and a “pH Probe” (which make up the “Gravity Analog pH meter V2”).

https://wiki.dfrobot.com/Gravity__Analog_pH_Sensor_Meter_Kit_V2_SKU_SEN0161-V2

The above web page states that:

“After completing the measurement, disconnect the pH probe from the signal conversion board. The pH probe should not be connected to the signal conversion board without the power supply for a long time.”

What is the reason for the above statement? Is it that the unpowered signal conversion board will “load” the pH probe in a way that will affect its lifetime?

We want to connect the probe and converter board to our battery powered logger with cellular telemetry. The logger would power up the converter board (3.3 volts) for a short time once an hour to get a pH reading and then turn off the power to the converter board while the logger is in a low power sleep mode. The pH probe would be connected to the converter board all the time, including when it is not powered.

If we can't do this then I guess the only option would be to design our own converter board that could be left permanently connected to the pH probe when not powered. Unless there is another off the shelf converter that could be used.

Thanks.