User manual HANNA INSTRUMENTS HI 991001

[. . . ] If the repair is not covered by the warranty, you will be notified of the charges incurred. If the instrument is to be returned to Hanna Instruments, first obtain a Returned Goods Authorization Number from the Customer Service department and then send it with shipment costs prepaid. When shipping any instrument, make sure it is properly packaged for complete protection. GENERAL DESCRIPTION HI 991001 is a portable, microprocessorbased pH and temperature meter. [. . . ] Note: When the meter detects the absence of a temperature probe at its input, the Automatic Temperature Compensation is turned off, and the meter uses a default value of 25°C (77°F) for the temperature measurement and compensation. In this condition, the secondary LCD shows 25. 0°C (77. 0°F) blinking. When a probe is connected, the meter automatically returns to the ATC mode, the ATC tag is turned on, and the temperature is shown on the secondary display. pH MEASUREMENT & CALIBRATION · Make sure the meter has been calibrated before use. · If the probe is dry, soak it in HI 70300 storage solution for one hour to reactivate it. · Stir briefly and wait until the symbol on the top left of the LCD is turned off. · The LCD shows the pH value (automatically compensated for temperature) on the primary LCD, while the secondary LCD shows the temperature of the solution. · If measurements are taken in different samples successively, rinse the probe tip thoroughly to eliminate cross-contamination. After cleaning, rinse the probe tip with some of the sample to be measured. 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. · From normal mode, press and hold ON/OFF/ MODE until OFF on the secondary display 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 replaces it with WRNG, indicating that 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 will show on the primary display the accepted buffer, with the message "OK 1" on the secondary display, and an audible signal is produced. After 1 second the meter automatically returns to the normal measuring mode. If a single-point calibration with buffers pH 7. 01 or 6. 86 is desired, then after the calibration point has been accepted the ON/OFF/MODE button must be pressed in order to return to the normal measuring mode. After the button is pressed, the meter shows "7. 01" (or "6. 86") - "OK 1", and an audible signal is produced. After 1 second, the meter automatically returns to the normal measuring mode. [. . . ] Change the set with the SET/HOLD button, then press ON/OFF/MODE to return to normal mode. BATTERY REPLACEMENT The meter displays the remaining battery percentage when turned on. When the level symbol on the bottom is below 5%, the left of the LCD blinks to indicate a low battery condition. If the battery level is low enough to cause erroneous readings, the Battery Error Prevention System (BEPS) turns the meter off. [. . . ]