Hanna Instruments HI 221 - Manual (Page 7)

7
OPERATIONAL GUIDE
POWER CONNECTION
Plug the 12 VDC adapter into the power supply socket.
Note: These instruments use non volatile memory to retain the pH, mV,
temperature calibrations and all other settings, even when unplugged.
Note: Make sure a fuse protects the mains line.
ELECTRODE AND PROBE CONNECTIONS
For HANNA P Type pH or ORP electrodes (with internal reference) connect the
electrode’s BNC to the socket on the back of the instrument and the pin to the
appropriate socket.
Note: Electrode condition and response information is displayed on the bar
graph gauges during the day the calibration is performed, only if
HANNA P type (PIN) electrodes are used.
If the electrode is not recognized as a HANNA P type electrode, the bar
graph gauges will blink (25 seconds OFF, 4 seconds ON, full bar graph).
For temperature measurement and automatic temperature compensation
connect the temperature probe to the appropriate socket.
INSTRUMENT START-UP
• Turn the instrument on by pressing the ON/OFF switch.
• All LCD tags are displayed and a beep is sounded
while the instrument performs a self test.
• The “Unscrew electrode refilling cap” message reminds the user to loosen
or remove the electrode refilling cap to improve the electrode’s response
time.
• The instrument automatically defaults to pH measurement mode unless a
HANNA P type ORP electrode is detected.
pH MEASUREMENT
Make sure the instrument has been calibrated before
taking pH measurements.
• Submerge the tip (4 cm/1½”) of a properly condi-
tioned electrode (see page 31) and the tempera-
ture probe into the sample to be tested. Allow time
for the electrode to stabilize.
CAL CFM
WRONG
DUE
CLEAR CAL if new electrode
CHECK
mV
LOG
ATC
BUFFER 12
RCL DEL pH
MTC
BUFFER CONTAMINATED
ELECTRODE
BUFFER
Unscrew electrode refilling cap SETUP
CLEAN
SLOW FAST POOR GOOD