Hanna Instruments HI 9910 - Manual (Page 22)

22
COARSE FINE CAL
mV
ORP
SET POINT
230
ORP CALIBRATION ORP CALIBRATION ORP CALIBRATION ORP CALIBRATION ORP CALIBRATION
(HI 9920)
4c
m (1
½
")
HI 7020
SET
READ
Make sure that the ORP 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.
Remove the electrode cap if it is still on the electrode.
During calibration, introduce both the electrode
and the ground probe (if in use) to the known
solution. An immersion level of 4 cm (1.5”) is
recommended.
If no separate ground probe is being used, make sure that the
Reference and the Matching Pin terminals are
shorted (see 14 - Functional Diagram).
If the electrode incorporates a ground probe/matching pin (HI 2003/3)
then remove the jumper.
• Turn the switch to the "READ" position.
• Immerse the electrode in a HI 7020 (or
another known) ORP solution and wait for
a few minutes for the reading to stabilize.
• Adjust the CAL trimmer to 230 ±20 mV (or a known value).
4c
m (1
½
")
HI 7020