PH sensor calibration
THIPPESWAMY.NAIK 2024-08-31 01:15:39 223 Views1 Replies Subject: Assistance Required for Calibration Method – Issue with Results
Hello DFRobot Support Team,
I am writing to seek your assistance regarding the calibration method described in the product documentation for Gravity Analog pH Sensor Meter (SEN0161-V2). Unfortunately, the results we are obtaining do not meet our requirements despite following the procedures as outlined.
To provide more context, I have attached a log file containing the readings we have taken during our calibration attempts. We have carefully reviewed the steps multiple times, but the output remains inconsistent with our expected results.
Could you please review the attached log file and advise us on the correct calibration procedure? Any guidance or additional troubleshooting steps you could provide would be greatly appreciated.
Thank you
Best regards,
Thippeswamy Naik
DFRobot_ph_sw_cal.zip Hello,
After reviewing the log you uploaded, I noticed that you calibrated the pH 7.0 point twice, and the measurement values of the pH 7.0 standard solution fluctuate significantly, which seems to be the issue.
When a pH sensor measures a neutral solution, the presence of fewer relevant ions can cause fluctuations in the measurements. If these fluctuations exceed the acceptable range, the Arduino code may consider the standard solution to have a significant error, leading to failure.
Therefore, when calibrating the sensor with a pH 7.0 standard solution, only one successful calibration is needed. You can then use another standard solution for further calibration.
The calibration of a pH sensor is a two-point calibration, using pH 7.0 and pH 4.0 standard solutions to calibrate the intercept and slope of the pH probe respectively. Therefore, please use these two standard solutions and perform a calibration once for each.
Additionally, please ensure that the pH sensor interface and the signal transmission board remain dry, as moisture may result in more neutral measurement values. You can use a hairdryer or similar device to heat and remove moisture.
Please strictly follow the steps in the tutorial to attempt recalibration: https://wiki.dfrobot.com/Gravity__Analog_pH_Sensor_Meter_Kit_V2_SKU_SEN0161-V2#target_3
Youyou 
