PART FOUR - SERVICE AND MAINTENANCE
SECTION 2 - PRESERVING MEASUREMENT ACCURACY
Rev. 6-501
Model P53 pH/ORP Analyzer (universal-mount 1/2 DIN)
91
S
ECTION
2
2.1 Keeping Sensor Clean
2.2 Keeping Analyzer
Calibrated
☞
2.3 Avoiding Electrical
Interference
☞
To maintain measurement accuracy, periodically clean the
sensor. Operating experience will help you determine the
intervals between cleanings (days, weeks, or months). Use
the recommended cleaning procedure described in the GLI
sensor operating manual.
Depending on the circumstances of the application, periodi-
cally re-calibrate the analyzer to maintain measurement
accuracy.
Maintenance Tip!
Upon startup, frequently check the
system until operating experience can determine the
optimum time between calibrations that provides ac-
ceptable measurement results.
•
pH:
Calibration using one of the methods described in
PART THREE, Section 5.2.
•
ORP: Calibration using only the method described in
PART THREE, Section 5.3.
Calibrating with old, contaminated, or diluted pH buffers may
cause measurement errors.
Do not reuse buffers.
Never pour
the portion of buffer used for calibration back into the buffer
bottle -- always discard it. Note that the pH value of a buffer
changes slightly as its temperature changes. (Always refer to
the pH value-versus-temperature table on the buffer bottle).
Therefore, always allow the temperatures of the sensor and
buffer to equalize while calibrating.
Recommendation:
Do not run the sensor cable (and inter-
connect cable, if used) in the same conduit with AC or DC
power wiring. Also, connect cable shielding as recom-
mended (PART TWO, Section 3.1, 3.2 or 3.3).
Maintenance Tip!
Excess cable should not be coiled
near motors or other equipment that may generate
electrical or magnetic fields. Cut cables to proper length
during installation to avoid unnecessary inductive pickup
(“electrical noise” may interfere with sensor signal).
PRESERVING MEASUREMENT ACCURACY
