User manual HANNA INSTRUMENTS HI 9146

[. . . ] 5 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Probe Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] · Make sure the probe is ready for measurement (see page 5), i. e. the membrane is filled with electrolyte and probe is connected to the meter and properly polarized. · "COND" appears on the display to inform you that ON/OFF the probe is in auto-conditioning (automatic polarization) mode. · Once "COND" disappears the probe is polarized and instrument can be calibrated. · For an accurate calibration, it is recommended to wait an additional 5 or 10 minutes to ensure optimum conditioning of the probe. Remove the protective cap. · · Press CAL. "----" appears on the larger LCD together with "CAL" to indicate that the instrument is in calibration mode. The instrument will automatically standardize itself to the actual saturation value. 1 minute it will show "100%" on the LCD and a small "SAMPLE" to indicate that the calibration is complete. CAL CAL SAMPLE % °C · Press FACTOR and ensure F1 and F2 are set to the appropriate altitude and salinity values (pages 10-11). Notes: · The instrument must be calibrated whenever the probe, membrane or the electrolyte is changed. · To exit the calibration mode during calibration, press CAL. · The display may be switched from readings in % saturation to mg/ CAL L without recalibration, by simply pressing RANGE. RANGE 8 9 MEASUREMENT 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 and ensure that the temperature sensor is also immersed. To display values in % saturation, press RANGE. RANGE If the sample contains significant salinity or if the measurement is taken at a higher altitude than sea level, the read-out values must be corrected (by taking into account the lower degree of oxygen solubility in such conditions - see below). Set the altitude and/or the salinity before calibration and taking mg/L measurements. The meter will automatically compensate for these factors. 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. A moving stream will provide adequate circulation. During field measurements, this condition may be obtained by manually stirring the probe. Accurate readings are not possible while the liquid is stationary. 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 membrane surface are minimized. For an accurate measurement, allow sufficient time for thermal equilibrium between the probe and the measurement sample (a few minutes if the temperature difference is several degrees). % O2 SATURATION READINGS The % O2 reading provides the rate of oxygen saturation with reference to 100. 0% at sea level. TEMPERATURE READINGS The lower part of the display will show the measured temperature in Celsius degrees. SAMPLE % °C Allow the probe to reach thermal equilibrium with the sample before taking any measurement. [. . . ] (03) 3258. 9565 · Fax (03) 3258. 9567 Korea: Tel. (02) 2278. 5147 · Fax (02) 2264. 1729 Malaysia: Tel. (603) 5638. 9940 · Fax (603) 5638. 9829 Singapore: Tel. 6296. 7118 · Fax 6291. 6906 South Africa: Tel. [. . . ]