Myron L PT3 - Manual (Page 4)

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a. In Hold mode when the LED turns on solid, remove the PT3 from
solution. The display will alternate between the final ORP and temperature
readings. Note the readings for your records.
b. In LIVE mode allow the PT3 to remain in solution while the LED flashes
slowly. The display will alternate between live ORP and temperature
readings. Note the readings for your records. LIVE measurement will time
out after 90 seconds OR push and release the push button to turn the
PT3 off at any time during LIVE measurement.
IV. Calibration
The Myron L Company recommends calibrating twice a month, depending on
usage. However, you should check the calibration whenever measurements are
not as expected.
The PT3 has automatic temperature compensation in calibration mode (from 15ºC to
30ºC). Temperature affects the reaction potentials for all chemicals differently. True
ORP is the direct measurement of electron activity during an oxidation-reduction
reaction, regardless of temperature. However, for maximum accuracy and ease of
calibration, the Myron L Company has developed three calibration solutions with
known dissolved species and embedded automatic temperature compensation for
those solutions into the calibration function of your PT3. To verify calibration while in
measurement mode, you must manually correct for temperature variations. For more
information, visit www.myronl.com/pt3.htm.
NOTE: If the measurement is NOT within calibration limits for any reason, “Error”
will display. Check to make sure you are using a proper ORP Standard Solution.
If the solution is correct, clean the sensor as described on page 4 under Routine
Maintenance. (Reconditioning the sensor should not be necessary due to the high
ionic strength of the calibration solutions.) Restart calibration.
NOTE: Small bubbles trapped in the sensor may give a false calibration. After
calibration is completed, measure the ORP Standard Solution again to verify
correct calibration. Remember, in measurement mode you must manually correct
for temperature variance from 25ºC. Example: At 25ºC, ORP2602OZ Standard
Solution will read 260mV; however, at 20.0ºC ORP2602OZ will read 265mV.
NOTE: If at any point during calibration, you do not submerge the sensor in solution
before the flashing slows, allow the PT3 to turn off and start over.
A. Calibration Preparation
1. Ensure the ORP sensor is clean and free of debris.
2. For maximum accuracy, pour a small amount of the calibration solution into
a separate container to rinse the sensor in prior to calibration. If this is not
possible, rinse the sensor in clean water prior to calibration.
B. Calibration
Use Myron L Company 80mV Quinhydrone, 260mV Quinhydrone, or 470mV
MLC Light’s ORP Standard Solution.
1. Thoroughly rinse the PT3 by submerging the sensor in ORP calibration rinse
solution and swirling it around.
2. Push and release the push button to turn the PT3 on.
3. Push and hold the push button. The display will alternate between “CAL”, “FAC
CAL”, “ºCºF TEMP”, “ModE SEL” and “ESC”.
4. Release the button when “CAL” displays. The display will indicate “CAL” and
the LED will flash rapidly.
5. While the LED flashes rapidly, dip the PT3 in ORP Standard Solution so that
the sensor is completely submerged.
6. While the LED flashes slowly, the display will indicate “ [value] CAL”; swirl the
PT3 around to remove bubbles, keeping the sensor submerged.
7. If the ORP calibration is successful, the display will indicate “CAL SAVEd”, then
time out.
8. Verify calibration by retesting the calibration solution.
C. factory Calibration
When ORP Standard Solution is not available, the PT3 can be returned to factory
default calibration using the FAC CAL function. This will erase any stored wet
calibration.
NOTE: default factory calibration resets the electronics only and does NOT take
the condition of the sensor into consideration.
To return your PT3 to factory calibration:
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