1. Displayed pH value
The number displayed for a pH reading can contain 3 types of data:
The first is of course a real decimal number, that represents the pH value of the solution being measured, it is made up of 5 digits, 3 of which are after the decimal point.
The second is 5 hyphens, all displayed pH results will contain this data. This signifies that the reference electrode does not give a valid response, therefore all pH calculations will be invalid. If this is shown on the screen or in the pH file data, please contact ANB Sensors.
The third is 5 $, which signifies that the system has not been able to determine a valid pH response yet. This could be due to a number of reasons, the most common of which is the health number.
2. Health Number
The health number represents the quality of data obtained from each individual sensor. The number ranges from 0 which is a healthy sensor, to 9 which is a sensor that will no longer be scanned.
A sensor with a health of 0 is scanned and its data is used in the monitoring of the pH of the solution and the quality and accuracy of other sensors in the array.
As a sensor starts to give a less accurate response, its health number is increased. It is a feature of this technology that a scanned sensor can improve its response as a consequence of being scanned, therefore as a sensor improves its response the health number can also be decreased, back towards zero and become a healthy sensor again.
Individual sensors with a health number from 1 to 8 continue to be scanned but the result calculated from the gathered data is not used in any cumulative data analysis. But rather if possible, to return a sensor to a working usable state.
Individual sensors whose health number reaches 9 are removed from the scan schedule and will no longer be used. They are deemed unrecoverable. They may be improved when the array is polished by hand.
If all the individual sensors scanned so far have a health number greater than 0, then the sensor cannot accurately determine the pH value. It will therefore display $$.$$$ as the pH number until it can scan a healthy individual sensor and use that data to calculate the pH.