72-900-06 Rev. F
Page 23 of 38
The probe is very sensitive to temperature changes. Allow the probe roughly 5
minutes to adjust to the temperature of the test solution or sample. Calibrating the
probe without allowing the probe to equilibrate to the sample temperature could
result in erroneous controller readings.
4.7.2.1 pH and ORP Probe Calibration (1 point)
Probe Calibration – Use this function to calibrate the probe. Enter the calibrated
value based on the calibration method used. For both methods shown below the
actual reading from the probe is shown on the screen. This is the un-calibrated value
the controller is receiving from the sensor. If the actual value displayed in the
calibration screen is not close to the sample that the probe is actually in, or the
reading is changing significantly, the probe either needs to be cleaned or replaced, or
the solution the probe is in is no longer accurate. Typically ORP does not require a
calibration for most applications for that reason only pH is illustrated below.
In-Stream (Best Practice)
Begin with a clean sensor. With the pH or ORP sensor installed in the
system under normal operating conditions ensure flow is going across the
probe for at least five (5) minutes for temperature equilibrium.
Step 1 – Move to the Probe Calibration screen.
Step 2 – Take a reading with a hand held tester from the sample valve on the
controllers flow assembly.
Step 3 – Observe that the actual reading displayed has stabilized then enter the
reading from the hand held tester as point 1. For the best results, this method
should be done with the system operating at, or within 1 pH unit, of the pH set
point.
Step 4 – Return to the Home Screen and verify the proper pH reading is
displayed.
Standard solution
Begin with a clean sensor, rinse the sensor with the standard solution to be
used for calibration purposes three (3) times, place the sensor in a
standard solution that represents the side of the pH scale for intended
control. For example, if the set point is above 7pH the standard should also
be above 7pH. With the sensor in the solution for at least five (5) minutes
for temperature equilibrium, observe that the actual value displayed has
stabilized and then enter the standard solution value as point 1.
pH Calibration
Actual 07.20 pH
Pt. 1 07.00 pH
To Next Page
Loading...
Need help?
General
