PART THREE - OPERATION
SECTION 4 - ANALYZER CALIBRATION
Rev. 6-1100
Model P33 pH/ORP Analyzer (panel-mount 1/4 DIN)
57
2 POINT SAMPLE
Method
8.
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.
9.
Press
ENTER key
to end calibration (“1 POINT
BUFFER: CONFIRM CAL OK?” screen appears).
10. Re-install the sensor into the process.
11. Press
ENTER key
to display the active measurement
reading on the “1 POINT BUFFER: CONFIRM AC-
TIVE?” output status screen. When the reading corre-
sponds to the actual typical process value, press
ENTER key
again to return the analog outputs and re-
lays to their active states (MEASURE screen appears).
This completes “1 POINT BUFFER” calibration.
This method requires you to enter the known values of two
solutions (samples or pH buffers). Determine sample pH
values by laboratory analysis or comparison readings.
1.
Immerse the sensor in the first solution (sample or
buffer).
Important: Allow the sensor and sample
temperatures to equalize.
Depending on their tem-
perature differences, this may take 30 minutes or more.
2.
Press
MENU key
to display a “MAIN MENU” screen.
If the
screen is not showing, use
Ø
Ø
or
×
×
key
to display it.
3.
Press
ENTER key
to display
.
4.
Press
ENTER key
again to display
.
