Orp calibration – Hanna Instruments HI 9912 User Manual

Page 14

4c
m

(1½")

HI 7010

OFFSET

SLOPE

ALARM

OFF

10.01

SLOPE ADJUSTMENT:

• Rinse the electrode (and ground probe)

thoroughly with water and immerse
the bottom 4 cm (1.5”) in a pH
10.01 (HI 7010) or a pH 4.01 (HI
7004) buffer solution.

• Stir the electrode and wait for the display to stabilize before

adjusting the "SLOPE" trim-
mer (see 5 - Functional
Diagram) to display pH
10.01 (or 4.01) on the LCD
if the temperature of the
buffer solution is at 25°C
(77°F). Otherwise, refer to
the chart at the end of the
manual for the buffer value and adjust the trimmer accordingly.

The pH calibration is now complete.

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 separate
ground probe (if in use) to the known solution. If no separate ground
probe is being used, make sure that the Reference
and the Matching Pin terminals are shorted (see
15 - Functional Diagram).
If the electrode (such as HI 2003/3) incorporates a ground probe
(matching pin) then remove the jumper.
• Immerse the electrode in a HI 7020 (or another known) ORP

solution and wait until the reading stabilizes.

• Adjust the CAL trimmer to 230 ±20 mV.

ORP CALIBRATION

4c
m

(1½")

HI 7020

CAL

ALARM

OFF

ORP

230