7
6
If measurements are taken successively in different samples, it is
recommended to rinse the electrode thoroughly with water and then
with some of the next sample to be measured.
pH readings are affected by temperature. In order for the meter to
measure the pH accurately, temperature must be taken into consid-
eration. To use the Automatic Temperature Compensation (ATC)
feature, submerge the
HI 7669/2W
temperature probe into the
sample as close to the electrode as possible and wait for a couple of
minutes.
If the temperature of the sample is known or tests are always
performed at the same temperature, you can simply manually
compensate for it. For this purpose the temperature probe must be
disconnected.
The display will then show the default tem-
perature of 25°C with the "°C" symbol blinking.
Note the temperature of the sample using a
ChecktempC
(
HI 98501
) or another accurate
thermometer as reference.
The temperature can now be adjusted with the
▲
°C and
▼
°C keys.
TAKING ORP MEASUREMENTS
An optional ORP electrode must be used to perform ORP measure-
ments (see accessories).
Oxidation-reduction potential (REDOX) measurements provide the
quantification of the oxidizing or reducing power of the sample tested.
To correctly perform a redox measurement, the surface of the ORP
electrode must be clean and smooth.
OPERATIONAL GUIDE
Power Connection
Plug the 12 Vdc adapter into the power supply socket.
Note:
Make sure the mains line is protected by a fuse.
Electrode and Probe Connections
Connect the BNC of the pH or ORP electrode to the BNC socket on the
rear panel.
For electrodes with a separate reference, connect the reference elec-
trode plug to the reference socket (#12 on page 4).
For temperature measurements and automatic temperature compen-
sation, connect the temperature probe to the appropriate socket.
Note:
To prevent damage to the pH electrode, remove it from the
solution before turning the meter off.
With the meter OFF, detach the electrode from the meter and
immerse it in the storage solution.
TAKING pH MEASUREMENTS
Make sure that the instrument has been calibrated for pH before
taking pH measurements.
• Switch the instrument on by pressing the
ON button. The meter automatically de-
faults to the pH measurement mode.
• Submerge the tip (4 cm / 1½") of the
electrode and temperature probe into the
sample to be tested. Allow a couple of
minutes for the electrode to stabilize.
• The pH reading is displayed on the primary LCD and temperature
on the secondary one.
• To view the mV reading, press the RANGE key.
4 cm
(1½")
