Xylem WQ pH SENSORS - Manual (Page 20)

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pH Calibration check
Step 1) Fill one container with tap water and another with 4 pH buffer
solution.
Step 2) Place the pH sensor into the container with 4 pH buffer. Turn
on the power supply and the current meter. Let the sensor
stabilize for 5 minutes before taking any measurements.
Step 3) Record the output current of the sensor, W = _______.
Remove the sensor and rinse it off in the tap water.
Step 4) Fill a container with 10 pH buffer solution.
Step 5) Place the pH sensor into the container. Turn on the power
supply and the current meter. Let the sensor stabilize for 5
minutes before taking any measurements.
Step 6) Record the output current of the sensor, X = _______. Remove
the sensor and rinse it off in the tap water.
Step 7) Subtract 4 pH current output from the 10 pH current output
,
X -
W = _______ = C.
Step 8) Calculate B. X – (C/6)(10)= _______ = B.
Step 9) Find the low current value for the sensor. B= _____ = L
C
. This
current is the output current the sensor would produce if the pH
were 0.
Step 10) Find the high current value for the sensor. (C/6)(14)+ B=
_____ = H
C
. This current is the output current the sensor would
produce if the pH were 14.
Step 11) Use these new current values to recalibrate the system that is
monitoring the sensor output.