Hanna Instruments HI 98186 User Manual

Page 11

INITIAL PREPARATION
The instrument is supplied complete with rechargeable batteries. Proceed with

a complete charging process before starting (see page 60).
To prepare the instrument for field measurements close the serial communica-

tion socket and all unused connector sockets with proper stopper (to ensure

waterproof protection).
Connect the DO probe to the 7-pin connector. Make sure that the probe sleeve

is properly inserted and tighten the threaded ring.
Turn the instrument ON by pressing ON/OFF key.
At start-up the display will show the Hanna logo for a few seconds , followed by

the percentage indication of the remaining battery charge, then enters the

probe conditioning mode. The probe will be conditioned for one minute, and

afterwards the instrument will enter measurement mode.
If the DO probe is not connected or is damaged, the conditioning period is

skipped.
To save battery life, the auto-off feature turns the instrument off after a set

period (default 30 min) if no button is pressed. To set another period or to

disable this feature, see SETUP menu on page 33.
The auto-off backlight feature turns the backlight off after a set period (default

1 min) with no buttons pressed. To set another period or to disable this

feature, see SETUP on page 33.

OPERATIONAL GUIDE

PROBE CONDITIONING
At startup, the probe is under polarization with a fixed voltage of approxi-

mately 800 mV for 1 minute.
Probe polarization is essential for stable measurements with the same recur-

ring degree of accuracy.
With the probe properly polarized, oxygen is continually consumed when it

passes through the sensitive diaphragm and dissolves in the electrolyte solu-

tion contained in the probe.
Whenever measurements are taken with a non-polarized probe, the oxygen

level revealed is both that of the tested solution, as well as that present in the

electrolyte solution. This reading is incorrect.
Keep the protective cap on during polarization time and remove it for calibra-

tion and measurements.