Hanna Instruments HI 5000 - Manual (Page 20)

20
pH pH pH pH pH CALIBRATION CALIBRATION CALIBRATION CALIBRATION CALIBRATION
Make sure that the pH electrode and any ground probe have been
properly connected and wired to the controller (see preceding pages)
and that the meter is plugged to the mains.
Calibration should be performed at a temperature similar to that of
the liquid to be monitored.
Use a Checktemp (or an accurate thermometer)
as reference.
Remove the electrode cap if it is still on the
electrode.
During calibration, move the electrode and the
separate ground probe (if in use) together from
one buffer to the next.
If no separate ground probe is being used, make
sure that the Reference and the Matching Pin
terminals are shorted (see 18 - Functional Dia-
gram).
If the electrode (such as HI 1003/3) incorporates a ground probe
(matching pin) then remove the jumper.
OFFSET ADJUSTMENT:
• Rinse the tip of the electrode with pH 7.01
solution (HI 7007), then dip the bottom 4 cm
(1.5”) of the electrode (and ground probe) in
the pH 7.01 buffer.
• Place the Checktemp thermometer in the buffer solution.
• Wait for the measurement to stabilize and then adjust the
"OFFSET" trimmer (see 7 - Functional Diagram) to display 7.01
on the LCD if the temperature of the buffer solution is at 25°C
(77°F).
4c
m (1½")
HI 7007
4c
m (1
½
")
HI 7007
pH
OFFSET SLOPE
ALARM
ON
OFF
7.01
4c
m (1
½
")
HI 7007