Municipal Instrumentation Calibration

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Of course, you'll have standard/s to compare with what value the communicator tells you How else can one know without comparing?

Single point calibration is iffy, so many protocols require multiple point calibration.
If you were doing base, acid and alkali three points pH calculation.

The sensors need to get tested directly in the reference solutions.

These reference solutions have to have tolerance better than what's required by calibration procedures. If the manual is not available, a good calibration technician should be able to determine what to use. The references are calibrated and their references are fully traceable to the source.

The values from reference solutions get keyed in, along with the relevant information that ensures proper traceability.

The existing sensor is then tested in reference solution(s)

If the calibration protocol requires 3 point references, you need to capture the before values at each point.

Calibration adjustments are then made AS NEEDED.

The tolerance might allow +/- 0.1, but the calibration adjustment protocol ma call for adjusting to fall within +/- 0.02. This is so that it does not deviate beyond +/- 0.1 until the next interval.

Adjustments are made. You repeat everything all over.
You then document the after values and other relevant factors like the solution temperature.

This becomes a part of vital record for processes or data that depend on the output from the instrument.

If you adjusted w/o capturing all the data, you screwed up irreversibly.

If something goes iffy, the work is traceable to you, which is traceable to the instruments you used and the pH solution is traceable to the manufacturer which uses processes traceable to higher standards and eventually going all the way to the national standards.

If you blame the pH solution was dud, then it can be proven or refuted by auditing.

You're not just going between rooms and resetting the clocks. You have to understand everything i talked about above and much more to be a competent metrology tech. If those clocks were part of a larger picture, you need a seamless link.

If something happens where the clock affects a larger picture, such as determining an important deadline, prior records, as-found after incident and a proper seal that locks out the calibration settings become critical in proving that before value, current value and other factors supports/refutes the claim and demonstrate that clock's deviation at the time of incident relative to the true time was within xx seconds with a quantifiable degree of certainty.