User manual HANNA INSTRUMENTS HI 96828

[. . . ] Follow the instructions of the measurement procedure for zeroing the meter. Under range: A blinking "0. 0" indicates that the sample absorbs less light than the zero reference. Check the procedure and make sure you use the same cuvette for reference (zero) and measurement. Over Range: A flashing value of the maximum concentration indicates an over range condition. [. . . ] A deposit could remain but it dose not affect the measurement. Time and way of shaking could sensitively affect the measurement. 9· Replace the cuvette into the holder and ensure that the notch on the cap is positioned securely into the groove. 10·Press and hold READ/ /TIMER for three seconds and the display will show the countdown prior to measurement or alternatively wait for 4 minutes and 30 seconds and press READ/ /TIMER. An audible "beep" indicates the end of countdown period. In all cases the lamp, cuvette and detector icons will appear on the display, depending on the measurement phase. 11·At the end of measurement, the instrument directly displays concentration in mg/L of nitrate-nitrogen on the LCD. To convert the reading to mg/L of nitrate (NO3-), multiply by the factor 4. 43. INTERFERENCES: or Interference may be caused by: 11 Ammonia and amines, as urea and primary aliphatic amines. Chloride above 100 mg/ L (negative interference). Chlorine above 2 mg/L (positive interference). Strong oxidizing and reducing substances. Note: To ensure accurate results, preform the tests at room temperature, between 18 °C and 28 °C (65 °F to 83 °F). For best result: Intensely colored samples or suspended matter in large amounts will cause interference. Therefore sample should be adequately treated before performing the test. 9· At the end of the measurement the display will show the validation standard value. The reading should be within specifications as reported on the CAL CHECKTM Standard Certificate. If the value is found out of specifications, please check that the cuvettes are free of fingerprints, oil or dirt and repeat validation. If results are still found out of specifications then recalibrate the instrument. 9 11·Then the date of last calibration (e. g. : "01. 08. 2009") appears on the display, or "01. 01. 2009" if the factory calibration was selected before. In both cases the year number is blinking, ready for date input. 12·Press GLP/ to edit the desired year (2009-2099). If the key is kept pressed, the year number is automatically increased. Calibration 13·When the correct year has been set, press ZERO/CFM or READ/ /TIMER to confirm. Now the display will show the month blinking. [. . . ] Use the Hanna CAL CHECKTM cuvettes (see "Accessories") to validate or calibrate instruments. 16·Press GLP/ to edit the desired day (01-31). If the key is kept pressed, the day number is automatically increased. Note: It is possible to change the editing from day to year and to month by pressing READ/ /TIMER. 17·Press ZERO/CFM to save the calibration date. [. . . ]