User manual HANNA INSTRUMENTS HI 98121

[. . . ] The glass bulb at the end of the electrode is sensitive to electrostatic discharges. Avoid touching the glass bulb and the ORP electrode at all times. Any variation introduced by the user to the supplied equipment may degrade the instrument's EMC performance. To avoid electrical shock, do not use this instrument when voltages at the measurement surface exceed 24 VAC or 60 VDC. [. . . ] Measuring unit for primary display ISTR98121 03/03 SPECIFICATIONS Range pH: ORP: Resolution pH: ORP: Temp: Accuracy (@20°C/68°F) pH MEASUREMENTS & CALIBRATION Taking measurements Select pH mode with the SET/HOLD button. Submerge the electrode in the solution to be tested while stirring it gently. The measurements should be taken when the stability symbol on the top left of the LCD disappears. The pH value automatically compensated for temperature is shown on the primary LCD while the secondary LCD shows the temperature of the sample. Note: Before taking any pH measurement make sure the meter has been calibrated (CAL tag present on the LCD). pH Calibration For better accuracy, frequent calibration of the instrument is recommended. In addition, the instrument must be recalibrated whenever: a) The pH electrode is replaced. Calibration procedure From normal measuring mode, press and hold the /MODE button until OFF on the secondary LCD is replaced by CAL. The LCD enters the calibration mode displaying "pH 7. 01 USE" (or "pH 6. 86 USE" if the NIST buffer set was selected). After 1 second the meter activates the automatic buffer recognition feature. If a valid buffer is detected then its value is shown on the primary display and REC appears on the secondary LCD. If no valid buffer is detected, the meter keeps the USE indication active for 12 seconds, and then it replaces it with WRNG, indicating the sample being measured is not a valid buffer. · For a single-point calibration with buffers pH 4. 01, 9. 18 or 10. 01, the meter automatically accepts the calibration when the reading is stable; the meter displays the accepted buffer, with the message "OK 1". After 1 second the meter automatically returns to the normal measuring mode. If a single-point calibration with buffer pH 7. 01 (or pH 6. 86) is desired, then after the calibration point /MODE button must be has been accepted the pressed in order to return to normal mode. After the button is pressed, the meter shows "7. 01" (or "6. 86") - "OK 1" and, after 1 second, it automatically returns to the normal measuring mode. Note: It is always recommended to carry out a twopoint calibration for better accuracy. -2. 00 to 16. 00 pH ±1000 mV 0. 01 pH 1 mV 0. 1°C or 0. 1°F ±0. 05 pH ±2 mV ±0. 5°C or ±1°F ±0. 02 pH ±2 mV ±0. 3°C or ±0. 6°F Automatic for pH -5 to 50°C (23 to 122°F); RH 100% pH: at 1 or 2 points with 2 sets of memorized buffers (pH 4. 01/7. 01/ 10. 01 or pH 4. 01/6. 86/9. 18) ORP: factory calibrated buffer (pH 4. 01, pH 10. 01, or pH 9. 18) is detected, then the meter completes the calibration procedure. When the buffer is accepted, the LCD shows the accepted value with the "OK 2" message, and then the meter returns to the normal measuring mode. Note: When the calibration procedure is completed, the CAL tag is turned on. To quit calibration and to reset to the default values · After entering the calibration mode and before the first point is accepted, it is possible to quit the procedure and return to the last calibration data by pressing the /MODE button. The secondary LCD displays "ESC" for 1 second and the meter returns to the normal measuring mode. · To reset to the default values and clear a previous calibration, press the SET/HOLD button after entering the calibration mode and before the first point is accepted. [. . . ] To change the batteries, remove the 4 screws located on the top of the meter. SETUP Setup mode allows the selection of temperature unit and pH buffer set. To enter the Setup mode, select pH mode and then press the /MODE button until CAL on the secondary display is replaced by TEMP and the current temperature unit (E. g. Then: · for °C/°F selection: Use the SET/HOLD button. After the temperature unit has been selected, press the /MODE button to enter the buffer set selection mode; press the /MODE button twice to return to the normal measuring mode. [. . . ]