In-Situ pH Sensor - Manual (Page 2)

Page 2
1. Fill the Cal Cup to the fill line with the selected
calibration solution and attach to the instrument.
a. With a full set of sensors installed, fill to the
lower line. With one or two sensors installed, fill
to the upper line.
2. Connect the instrument to a PC, open Win-Situ 4 or
Pocket-Situ 4 software, and click Find to connect to
the device. Select the instrument in the Navigation
tree. The software will automatically detect and
display the installed sensors.
3. Click Parameters, select pH, then click Calibrate.
4. In the pH Calibration Wizard, specify how many
calibration points you intend to use, and the
solution for each. Click Next and follow the wizard
to perform a 2- or 3-point calibration. Be sure to
rinse the Cal Cup and sensors between solutions.
5. At the end of the Wizard, click Finish to write the
newly calculated calibration coefficients to the
sensor. The pH sensor is now calibrated and ready
to use.
If the instrument will be used in a day or so, leave the
sensors installed. Remove the Cal Cup and rinse it and
the sensors. Add about 50-100 mL of tap water to the
Cal Cup. Return the probe to the Cal Cup for transport
to the field site.
Calibration Notes:
• pH 4, pH 7, and pH 10 buffers are available from
In-Situ Inc. for pH calibration. Always begin with the
lowest buffer value when performing a multi-point
calibration.
• Ensure that every port is filled with a sensor or a
plug before calibrating.
• For best results, try to calibrate at the same
temperature as the expected sample temperature.
• Prior to calibrating, rinse the Cal Cup and the front
end of the TROLL 9500 in clean water, and shake
dry. For best results, follow this with a second rinse
in a portion of the calibration solution.
• The Cal Cup fill line indicates the approximate
amount of solution to use. Fill to the upper line with
1-2 sensors installed; fill to the lower line with more
sensors installed. The temperature sensor should be
submerged at least one half inch.
• Most sensors stabilize in 1 to 3 minutes if
properly hydrated before calibration. To minimize
stabilization time, do not handle the instrument
during calibration readings.
• To shorten the calibration time, you have the option
to accept the calibration when stability is “Nominal.”
If the early value is accepted, the calibration point
will be designated “USER SET” in the calibration
report. If the calibration was performed through to
stability then the sensor will operate according to
specifications.
• Cal solutions may be flushed down the drain with
running water, or saved in a separate container and
used to rinse the next time you calibrate with the
same solution.
• A calibration report in HTML format is created for
each calibration—even one that was cancelled. You
can view the report right after calibrating, or at any
time. See “Calibration History” in Section 10 of the
TROLL 9500 Operator’s Manual for details.
• Calibrate the sensor after replacing the reference
junction and/or the filling solution, during routine,
scheduled maintenance, or every 2-6 weeks in the
absence of other indicators.
Indicators During Calibration:
NOT TESTED is displayed until Run is selected.
UNSTABLE indicates the sensor response does not
meet the criteria for a valid calibration point.
NOMINAL indicates the sensor deviation meets early
stabilization criteria. The Accept button becomes
available when stability is nominal. You may accept the
early value, or wait for complete stability. If you accept
the early value, the calibration point will be designated
“USER SET” in the calibration report.
Figure 2. Win-Situ 4 Calibration