Hanna Instruments HI 9143 - Manual (Page 3)

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FUNCTIONAL DESCRIPTION - PROBE
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1. D.O. probe
2. Protective cap
3. Watertight shielded cable
4. Polypropylene body
5. Temperature sensor
6. O-Ring seal
7. AgCl (silver chloride) anode
8. Platinum cathode
9. Oxygen permeable membrane
10. Membrane cap
FUNCTIONAL DESCRIPTION - METER
1) Battery compartment
2) Probe connector
3) Liquid Crystal Display (LCD)
4) ON/OFF key
5) CAL key, to enter/exit calibration mode
6) FACTOR* key, to select altitude (F1)
and salinity (F2)
7) UP* and DOWN* arrow keys, to set F1
and F2 values
8) HOLD key, to freeze reading on display
9) RANGE key, to select oxygen measure-
ment range (ppm or % of saturation)
10) Socket for 12 Vdc power adapter
19) “LOW BAT”, low battery indicator
20) “SAMPLE”, measuring mode indicator
21) “F1”, altitude factor* indicator
22) “F2”, salinity factor* indicator
23) “%” or “ppm”, oxygen measure unit
24) Secondary display
(*) HI 9143 only
HI 9143
Microprocessor
Auto Cal
Dissolved
Oxygen Meter
CAL
ON/OFF
RANGE
FACTOR
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SAMPLE
LOBAT
SAMPLE
HOLD
CAL F1
F2
HOLD
ppm
ppm
%
°C
°C
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The dissolved oxygen probe is provided with a
membrane covering the polarographic sensor
elements, and a built-in thermistor for tempera-
ture measurement and compensation.
The thin permeable membrane isolates the
sensor elements from the testing solution, but
allows oxygen to enter.
When a voltage is applied across the sensor,
oxygen that passes through the membrane
causes a current to flow from which the oxygen
concentration is determined.