Hanna Instruments wm 8910 User Manual

3 1

3 0

Make sure that the controller with the electrode or probe installed is
calibrated before operating (see pages 27-30).

FOR WM 8910

Turn the switch to the "SET" position. The display will show the set
value (e.g. pH 8.00).

Using a small screwdriver, first adjust the setpoint through the
COARSE trimmer, then fine tune it to your required level with the
FINE trimmer until the desired set value is displayed (e.g. pH 6.00).

HOW TO SELECT THE DOSING DIRECTION

Select the direction of dosing through the "CONTROL
SELECT" terminals. For an acid dosage short the
"ACID" and common terminals.

For an alkaline dosage, short the "BASE" with the
common (middle) terminal.

E.g. How to dose acidic liquids
Setpoint = pH 6.00
Measured value = pH 7.00
To reach the setpoint you need to dose acid, therefore
connect the "ACID" to the middle terminal of "CONTROL
SELECT".

• Immerse the probe into a beaker with a

known calibration solution preferably close
to the value of the sample stream
(HI 7039L at 5000 µS/cm is recom-
mended for slope calibration). The level of
solution must be higher than the holes
on the PVC sleeve.

• Tap the probe repeatedly on the bottom of the beaker and stir it

to ensure that no air bubbles are trapped inside the sleeve.

• When the reading stabilizes, turn the "SLOPE" or the "5.0 mS"

trimmer until the LCD reading is the same of the calibration
solution at the liquid temperature.

• If the instrument will not calibrate refer to the Probe Maintenance

and Cleaning section (see page 45).