PART THREE - OPERATION
SECTION 4 - ANALYZER CALIBRATION
Rev. 6-1100
Model P33 pH/ORP Analyzer (panel-mount 1/4 DIN)
59
12. Immerse the sensor in the second solution, and press
ENTER key
to confirm. This active
screen appears showing the measurement reading.
13. Wait for the reading to stabilize which may take up to
30 minutes. Then press
ENTER key
. The “PLEASE
WAIT” screen may appear if the reading is still too un-
stable. After the reading has stabilized, this static
screen appears showing the “last”
measured value.
14. Determine the pH value of the second solution.
15. With the static
screen displayed,
use
arrow keys
to adjust the displayed value to exactly
match the known pH value of the second solution. Then
press
ENTER key
to enter the value, completing cali-
bration of the second point.
16. A “pH SLOPE XX.X mV/pH” screen appears, indicating
a slope value to measure sensor performance. The
slope should be between 54 and 62 mV/pH for optimal
performance. Typically, as the sensor ages and/or be-
comes dirty, its slope decreases. When the slope
decreases below 54 mV/pH, clean the sensor to im-
prove its performance. If the slope remains low and you
are using a GLI Differential sensor, replace the salt
bridge and standard cell buffer (see sensor instruction
manual for details). If using a conventional combination
electrode, consider replacing it.
17. Press
ENTER key
to end calibration (“2 POINT
SAMPLE: CONFIRM CAL OK?” screen appears).
18. Re-install the sensor into the process.
19. Press
ENTER key
to display the active measurement
reading on the “2 POINT SAMPLE: CONFIRM ACTIVE?”
output status screen. When the reading corresponds to
the actual typical process value, press
ENTER key
again to return the analog outputs and relays to their
active states (MEASURE screen appears).
This completes “2 POINT SAMPLE” calibration.
