15
3.
The coating or abrasive nature of the application.
4.
The stability of the sensor and controller as a system.
The frequency of calibration is really determined by experience. At a
new installation, calibration might initially be checked every day by
comparing the controller reading to a DPD test or other manual analysis
and logging the results. If the reading drifts off significantly in one
direction you should consider calibrating. Resist the temptation to
calibrate to correct for small errors that may be a result of normal
variations in the test methods.
A calibration MUST be performed on initial installation, or after
cleaning the electrodes, or after replacing the electrolyte. A sensor
installed in clean water can hold its calibration for several months.
DO NOT attempt to perform a calibration until the following conditions
have been met:
1.
The sensor has been conditioned as described above.
2.
The sensor has equilibrated to the temperature of the water (for the
zero calibration) or the sample (for the 1 point process calibration).
Zero Calibration
1.
Remove the sensor from the flow cell and place it in a beaker of clean,
oxidizer-free water.
2.
Allow the sensor 1 hour to equilibrate.
3.
Go to the Zero Calibration menu of the controller. Refer to the controller
instructions.
4.
Stir the water with the sensor until the mV reading is stable for at least 5
minutes.
5.
When the reading is stable, continue to the final steps of the calibration.
6.
Return the sensor to the flow cell and check for leaks.
One Point Process Calibration
1.
Ensure that the sensor is conditioned and equilibrated to the temperature
of the sample.
2.
Ensure that the sample flow rate is between 20 and 100 liters/hour. The
acrylic flow cell has a flow regulator knob on the lower left hand side.
3.
Perform a DPD test or other manual analysis on the sample water.
4.
Go to the One Point Process Calibration menu of the controller. Refer to
the controller instructions.
5.
When the reading is stable, continue to the final steps of the calibration.
Summary of Contents for WDS100
Page 9: ...6 Typical Installation...
Page 16: ...13 W900...
