PART THREE - OPERATION
SECTION 5 - ANALYZER CALIBRATION
Model P53 pH/ORP Analyzer (universal-mount 1/2 DIN)
Rev. 6-501
66
5.
Use
Ø
Ø
key
to select the “1 POINT SAMPLE” line and
press
ENTER key
to display
. Use
×
×
or
Ø
Ø
key
to view the three states that the analog outputs
(and relays) can be in during calibration:
•
HOLD OUTPUTS:
Holds their present values.
•
XFER OUTPUTS:
Transfers to preset values.
•
ACTIVE OUTPUTS:
Responds to measured values.
With the desired choice displayed, press
ENTER key
to
enter this selection.
6.
With the sensor in the sample (or buffer) and the
screen displayed, press
ENTER key
to
confirm. This active
screen appears
showing the measurement reading.
7.
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.
8.
Determine the pH value of the sample using laboratory
analysis or a calibrated portable pH meter. (When us-
ing a pH buffer, refer to the table on the buffer bottle to
find the exact pH value corresponding to the tempera-
ture of the buffer.)
9.
With the static
screen displayed, use
arrow keys
to adjust the displayed value to exactly
match the known pH value of the sample (or buffer).
Then press
ENTER key
to enter the value, completing
calibration of the point.
10. 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
sensor performance. Typically, as the sensor ages
and/or becomes dirty, its slope decreases. When the
slope is less than 54 mV/pH, clean the sensor to im-
prove its performance. If you are using a GLI
Differential sensor and the slope remains low, replace
the salt bridge and standard cell solution (see sensor
