Hanna Instruments HI 255 - Manual (Page 7)

7
OPERATIONAL GUIDE
POWER CONNECTION
Plug the 12 VDC adapter into the power supply socket.
Note: This instrument uses non volatile memory to retain the calibration
parameters and all other settings, even when unplugged.
Note: Make sure a fuse protects the main line.
ELECTRODE AND PROBE CONNECTIONS
For pH or ORP measurements connect an electrode with internal reference to
the BNC connector on the back of the instrument.
For electrodes with a separate reference connect the electrode’s BNC to the BNC
connector and the reference electrode plug to the reference socket.
For temperature measurements and automatic temperature compensation
connect the temperature probe to the appropriate socket.
For EC/TDS measurements connect the probe to the 7-pin connector. Make sure
the probe sleeve is properly inserted.
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.
Note:
•
The instrument starts in the same range and mode as it was at
power off.
•
The RANGE key toggles between pH, mV and EC ranges.
•
The ALT&MODE keys changes the displayed information for the
selected range.
pH MEASUREMENTS
Make sure the instrument has been calibrated before taking
pH measurements.
• Press RANGE to enter pH range.
Note: To select pH resolution press the ALT&MODE keys.
• Submerge the electrode tip and the temperature probe
approximately 4 cm (1½”) into the sample to be tested
and stir gently. Allow time for the electrode to stabilize.