User manual HANNA INSTRUMENTS HI 122

[. . . ] Instruction Manual HI 120 & HI 122 pH/mV/Temperature Bench Meters with Calibration Check ON OFF HI 122 pH / mV Meter CAL CFM CLR LOG Calibration Check w w w. c o m 1 Dear Customer, Thank you for choosing a Hanna Instruments product. Please read this instruction manual carefully before using the instruments. This manual will provide you with the necessary information for correct use of the instruments, as well as a precise idea of their versatility. [. . . ] Notes: · Press MODE to select another resolution if the displayed value allows it (e. g. if 199. 9 is displayed, by pressing MODE the value will change to 1999; if 19. 9 is displayed, nothing will happen if pressing MODE). · Press NUM from the left keyboard if you want to change the value using the numerical keys. · When the reading is stable, in mV range and the Relative mV offset is inside the offset window (±2000 mV), "CFM" tag blinks. · If the absolute mV reading is out of range or the Relative mV offset is out of the offset window, "WRONG" tag will blink. Change the input value or the Relative mV offset to complete the calibration process. 22 GOOD LABORATORY PRACTICE (GLP) GLP is a set of functions that allows storage and retrival of data regarding the maintenance and status of the electrode. All data regarding pH and Rel mV calibration is stored for the user to review when necessary. CALIBRATION ALARM TIME OUT For pH calibration, all the instruments allow the user to set the number of days before the next required pH calibration. If the time elapsed, "CAL DUE" tags will blink as a reminder. Note: If the instrument was not calibrated or all calibration parameters were cleared, "CAL" "DUE" tags will be displayed even if the feature is disabled in SETUP menu. LAST pH CALIBRATION DATA The last pH calibration data is stored automatically after a successful calibration. To view the pH calibration data, press 2nd then GLP key or simply GLP from the left keyboard (HI 120) when the instrument is in pH (mV) measurement mode. The instrument will display the date (yyyy. mm. dd) of the last calibration. Press the ARROW keys to view the next calibration parameter (pressing the key): · The time (hh:mm) of the last calibration. 23 · The pH calibration offset. · The pH calibration slope (the GLP slope is the average of the calibration slopes; the percentage is referred to the ideal value of 59. 16 mV/pH). · The calibration buffers in calibrating order, with the corresponding warnings. The first pH calibration buffer: The second pH calibration buffer: The third pH calibration buffer: 24 The fourth pH calibration buffer: The fifth pH calibration buffer: Notes: · The "OLd" message displayed beside the pH value means that this buffer was not used during last calibration. Press 2nd then SET key if you want to see calibration date (or time, if old calibration was performed in the same day with current calibration). · Each calibration buffer is displayed with the resolution from calibration moment. · If "no bUF" message appears on the LCD, the instrument informs you that calibration was performed in less than five points. If disabled, or the number of days until the calibration alarm will be displayed (e. g. · The instrument ID. 25 LAST RELATIVE mV CALIBRATION DATA Last Relative mV calibration data is stored automatically after a successful calibration. To view the Relative mV calibration data, press 2nd then GLP key or simply GLP from the left keyboard (HI 120) while in Relative mV measurement mode. · The date (yyyy. mm. dd) of the last calibration as in pH GLP mode. Press the ARROW keys to view the next logged calibration parameter (pressing the key): · The Relative mV calibration offset and time (hh:mm) as in pH GLP mode. [. . . ] In addition, the response time will suffer to a greater degree at temperatures below 25 ºC (77 ºF). Since the resistance of the pH electrode is in the range of 50 ­ 200 Mohm, the current across the membrane is in the pico Ampere range. Large currents can disturb the calibration of the electrode for many hours. For these reasons high humidity environments, short circuits and static discharges are detrimental to a stable pH reading. If constantly used at high temperatures, the electrode life is drastically reduced. [. . . ]