PART THREE - OPERATION
SECTION 4 - ANALYZER CALIBRATION
Rev. 6-1100
Model P33 pH/ORP Analyzer (panel-mount 1/4 DIN)
55
1 POINT BUFFER
Method
☞
Thereafter, a screen like
appears
for 5 seconds to confirm calibration of this point.
9.
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.
10. Press
ENTER key
to end calibration (“2 POINT
BUFFER: CONFIRM CAL OK?” screen appears).
11. Re-install the sensor into the process.
12. Press
ENTER key
to display the active measurement
reading on the “2 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 “2 POINT BUFFER” calibration.
This method is similar to the 2 POINT BUFFER method ex-
cept that only one buffer is used to calibrate one point. This
method also automatically recognizes buffers from the
buffer set you selected. Therefore, you must use a buffer
that matches a value in the buffer set. (See PART THREE,
Section 3.2, subheading “SELECT BUFFER Set” for selec-
tion details.)
NOTE:
When you want to use a buffer not included in ei-
ther of the analyzer buffer sets, disregard this
calibration method. Instead, calibrate using only the
“1 POINT SAMPLE” method.
1.
Immerse the sensor in the pH buffer.
Important: Allow
the sensor and buffer temperatures to equalize.
De-
pending on their temperature differences, this may take
30 minutes or more.
