8
Calibration and Verification
Two steps ensure best accuracy…
1. Calibration:
typically performed by the manufacturer. All probes
include a Certificate of Calibration.
2. Verification of Accuracy:
typically performed by the user by
measuring known reference standards such as the supplied
conductivity standard.
Calibration
- Calibration is the high-level, controlled and
documented process of measuring traceable calibration standards
over the full operating range of the probe, and verifying that the
results are within the stated accuracy of the probe. Calibrations are
performed by the manufacturer, their authorized agent, or by an
accredited calibration laboratory in a controlled environment using
a documented process
Verification of Accuracy
- Verification is an accuracy check
performed by the user with a solution of known conductivity. To
perform a verification, ensure that the conductivity standard and
instrument are at the same temperature. Remove any remaining
DI water in the test cell by filling it with the conductivity standard,
then inverting the test cell to empty it. Fill the test cell with the
conductivity standard again. If the reading is not within the
combined tolerance of the gage and conductivity standard,
proceed to
Cleaning the Test Cell
, below.
Cleaning the Test Cell
- If the Verification reading is outside the
combined accuracy of the conductivity standard and gage, the
probe may need to be cleaned by filling it with DI water and
rubbing the walls of the cell with a supplied foam tip swab. Rinse
with DI water several times before using the cell.
Verify accuracy at the beginning and the end of each work shift.
During the work shift, if the Gage is dropped or suspected of giving
erroneous readings, its accuracy should be re-verified.
