User manual HANNA INSTRUMENTS HI 9143

[. . . ] 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. FUNCTIONAL DESCRIPTION - METER 2 10 1 2 SAMPLE ppm 10 3 °C 19 HI 9143 Microprocessor Auto Cal Dissolved Oxygen Meter ON/OFF 20 9 8 21 22 LOBAT SAMPLE HOLD F1 F2 ppm % 23 24 4 5 CAL CAL °C RANGE HOLD FUNCTIONAL DESCRIPTION - PROBE 6 FACTOR 7 3 1 4 6 7 8 4 9 5 1) 2) 3) 4) 5) 6) 2 6 7 8 9 7) 8) 9) 10) 19) 20) 21) 22) 23) 24) 10 1. probe Protective cap Watertight shielded cable Polypropylene body Temperature sensor O-Ring seal AgCl (silver chloride) anode Platinum cathode Oxygen permeable membrane Membrane cap Battery compartment Probe connector Liquid Crystal Display (LCD) ON/OFF key CAL key, to enter/exit calibration mode FACTOR* key, to select altitude (F1) and salinity (F2) UP* and DOWN* arrow keys, to set F1 and F2 values HOLD key, to freeze reading on display RANGE key, to select oxygen measurement range (ppm or % of saturation) Socket for 12 Vdc power adapter "LOW BAT", low battery indicator "SAMPLE", measuring mode indicator "F1", altitude factor* indicator "F2", salinity factor* indicator "%" or "ppm", oxygen measure unit Secondary display (*) HI 9143 only 4 5 SPECIFICATIONS PROBE PREPARATION All HANNA D. O. To hydrate the probe and prepare it for use, connect it to the meter and proceed as follows. [. . . ] · "COND" appears on the display to inform the user that ON/OFF the probe is in auto-conditioning (automatic polarization) mode. · Once "COND" disappears, the probe is polarized and the instrument can be calibrated. · · · Press CAL. The disply shows "----" together with the "CAL" symbol to indicate that the instrument is in calibration mode. The instrument will automatically standardize itself to the actual saturation value. 1 minute it will display "100%" with "SAMPLE" to indicate that the calibration is complete. CAL CAL SAMPLE % °C · HI 9143 only: press FACTOR and ensure that F1 and F2 are set to the appropriate altitude and salinity values. Notes: · The instrument must be calibrated whenever the probe, membrane or electrolyte is changed. CAL · The display may be switched from readings in % saturation to ppm (mg/L) by simply RANGE pressing the RANGE key. Recalibration is not needed. 8 9 TAKING MEASUREMENTS Make sure the meter has been calibrated and the protective cap has been removed. Immerse the tip of the probe in the sample to be tested ensuring that the temperature sensor is also immersed. To display values in % saturation, press RANGE. RANGE For accurate dissolved oxygen measurements, a water movement of at least 30 cm (12")/sec is required. This is to ensure that oxygen depleted on the membrane surface is constantly replenished. During field measurements, this condition may be obtained by manually stirring the probe. During laboratory measurements, the use of a magnetic stirrer to ensure a certain agitation of the fluid is recommended. This way, any errors due to the presence of air bubbles on the menbrane surface are minimized. For accurate measurements, allow sufficient time for the thermal equilibrium to be reached between the probe and the measured sample (a few minutes if the temperature difference is several degrees). mg/L READINGS The mg/L mode give the dissolved oxygen concentration directly in ppm. If the sample contains significant salinity or if the measurement is taken at a higher altitude than sea level, the readout values must be corrected, by taking into account the lower degree of oxygen solubility in such conditions. Compensation for altitude and sality effects is possible with the HI 9143 model. Altitude and/or salinity values should be set before calibrating and taking measurements. The meter will automatically compensate for these factors (see "Altitude Compensation" and "Salinity Compensation" sections). % O2 SATURATION READINGS The % O2 reading provides the rate of oxygen saturation with reference to 100% at sea level. SAMPLE % °C TEMPERATURE READINGS The secondary display will show the sample temperature in Celsius degrees. Allow the probe to reach thermal equilibrium with the sample before taking any measurement. The greater the difference between the ambient temperature and the temperature of the sample, the longer it will take the probe to acclimatized itself to the sample. 10 11 ALTITUDE COMPENSATION HI 9143 Press FACTOR and "F1" will be displayed. Use the UP and DOWN keys to set the altitude from 0 to 1900 m, in steps of 100 m. SALINITY COMPENSATION HI 9143 Press FACTOR twice and "F2" will be displayed. Press FACTOR again to display the temperature. SAMPLE ppm SAMPLE ppm F1 F2 or or HI 9145 With HI 9145, all the DO readings refer to the sea level. [. . . ] When shipping any instrument, make sure it is properly packaged for complete protection. All rights are reserved. Reproduction in whole or in part is prohibited without the written consent of the copyright owner. Hanna Instruments reserves the right to modify the design, construction and appearance of its products without advance notice. 18 Recommendations for Users Before using these products, make sure that they are entirely suitable for the environment in which they are used. Operation of this instrument in residential area could cause unacceptable interference to radio and TV equipment, requiring the operator to take all necessary steps to correct interferences. [. . . ]