9
OPERATIONAL GUIDE
POWER CONNECTION
Plug the 12 Vdc adapter into the power supply socket.
Notes:
• These instruments use non-volatile memory to retain the pH, ISE calibrations and all other
settings, even when unplugged.
• Make sure a fuse protects the main line.
ELECTRODE AND PROBE CONNECTIONS
For pH or ORP measurements, connect a pH/ORP electrode with internal reference to the BNC connector
located on the rear panel of the instrument (to the desired channel -
HI 5222
only).
For ISE measurements, (
HI 5222
only) connect, to the desired channel, an ISE electrode with internal
reference to the BNC connector located on the rear panel of the instrument.
For electrodes with a separate reference, connect the electrode’s BNC to the BNC connector and the electrode’s
reference to the reference input socket.
For temperature measurement and automatic temperature compensation, connect the temperature probe to the
appropriate socket (to desired channel -
HI 5222
only).
INSTRUMENT START UP
• Please ensure that the capacitive keypad is not covered by hand or other objects at the meter power on.
• Turn the instrument on from the power button located on the rear panel of the instrument.
• Please wait until the instrument finishes the initialization process.
Note:
It is normal for the loading process to take a few seconds. If the instrument doesn’t display the next
screen, restart the meter using the power button. If the problem persists, contact your dealer.
72
TEMPERATURE CORRELATION FOR pH SENSITIVE GLASS
The resistance of glass electrodes partially depends on the temperature. The lower the temperature, the
higher the resistance. It takes more time for the reading to stabilize if the resistance is higher.
Since the resistance of the pH electrode is in the range of 50 – 200 Mohm, the current across the
membrane is in the pico Ampere range. Large currents can disturb the calibration of the electrode for many
hours.
The pH electrode’s life also depends on the temperature. If constantly used at high temperatures, the
electrode life is drastically reduced.
Typical Electrode Life
Ambient Temperature
1 – 3 years
90 °C (194 °F)
Less than 4 months
120 °C (248 °F)
Less than 1 month
Alkaline Error
High concentrations of sodium ions interfere with readings in alkaline solutions. The pH at which the
interference starts to be significant depends upon the composition of the glass. This interference is called
alkaline error and causes the pH to be underestimated.
