FAQs

1. How do traditional pH Sensors work?

Currently, traditional current potentiometric pH sensors measure the voltage between two electrodes – a glass electrode and a reference electrode. These are often combined forming a standard combination pH sensor.

When the glass electrode and the reference electrode are placed in the test solution, an electrical circuit is completed, in which there is a potential difference created, amplified and detected by the voltmeter.

These glass pH electrodes need to be frequently calibrated to overcome the reference signal drift.

2. Can you reduce the frequency of calibrations?

Yes! ANB Sensors have developed a novel technology looking at a solution to this problem from a completely new angle. Developing ways to delay reference electrode drift, or in some cases predicting it. It can’t be stopped entirely as it is intrinsic to the sensor. So instead,  a novel way was developed to track the drift, thereby allowing the sensor to self-calibrate.

It works by placing a second electrode into the reference chamber, alongside the reference electrode. This reference tracking electrode periodically measures for any drift in the reference electrode and then automatically compensates for this in the pH measurement.

3. What are the advantages of not having to calibrate?

Without having to manually calibrate, many more sensors can be deployed and entire water networks can be monitored. This is of particular relevance with the increase in regulations. As the accuracy of the measurement over time is no longer an issue, the sensors can be meaningfully networked into the IoT with complete confidence in the pH readings gathered. There will be no down time of the sensor – the erroneous measurements taken when the sensor has lost accuracy and is waiting to be recalibrated will be a thing of the past. Along with the labour cost saving for the engineer who currently goes out to calibrate the sensors, there is also the environmental impact of travel, logistics and calibration standards that will be avoided.