User manual HANNA INSTRUMENTS HI 98240

[. . . ] Instruction Manual HI 98230 · HI 98240 Printing and Logging pH Meters with GLP and Smart Electrodes www. hannainst. com Dear Customer, Thank you for choosing a Hanna Instruments Product. Please read this instruction manual carefully before using the instrument. This manual will provide you with all the necessary information for the correct use of the instruments. If you need additional technical information, do not hesitate to e-mail us at tech@hannainst. com. [. . . ] If a wrong solution or electrode has been used or if the buffer is polluted, "WRONG" will be displayed to alert the user. If only a single point calibration is required, press ALT and CAL to leave the calibration mode and maintain the previous slope calibration. The instrument then checks the electrode parameters and advises user of abnormalities by "old probe" and "dead probe" indications. Rinse the electrode with some of the second buffer solution or clean water. Dip the bottom, 4 cm (1½"), of the electrode in a beaker containing the second buffer. When the "S" symbol blinks in the lower LCD, press ALT and CFM to confirm the second calibration point. CALIBRATION DATA PRINTOUT It is possible to print the characteristics of the electrode as a recording of the electrode performance over time by setup code 12 (see "Printing GLP data"). This will consist of: date, time, the offset characteristic of the pH electrode in mV, the slope characteristic in mV/pH and the pH buffer solution values. If calibration has been performed with an "old" pH electrode the first line is: pH ** If calibration has been performed with a "dead" pH electrode the first line is: pH -If the calibration alarm time-out is expired, the "Dt" string will be printed beside the date. Note: A dashed line indicates that the calibration has never been performed. 18 19 mV CALIBRATION PROCEDURE (HI 98240 ONLY) A 4 point calibration must be performed. The first two calibration points are 0 and 350 mV for low range calibration; the other two points are 0 and 350 or 1900 mV for high range calibration. Connect a mV simulator (HI 8427 or HI 931001 with the proper connection cable) to the meter and set it to 0 mV. User is prompted to enter password if it has been set to a value different from 0000, otherwise skip to step 6. Press ALT and CFM to confirm the password or ALT and CAL to return to normal operational mode. If password is correct or not set, the meter will display "0. 0 mV" on the upper LCD and "b1" on the lower; if wrong, it will return to normal operational mode without any message. When the "S" symbol blinks in the lower LCD, the reading is stable and calibration can be confirmed. When the "S" symbol blinks in the lower LCD, the reading is stable. The meter will display "350 mV" in the upper LCD and "b4" on the lower one. Pressing the " " key, 1900 mV will be selected as calibration point. Note: +1900 mV is suggested as the last calibration point to obtain the best accuracy throughout the entire mV range. When the "S" symbol blinks in the lower LCD, the reading is stable. Calibration is now complete and the instrument returns to normal operational mode. Note: "Err" message notifies the user if the selected value is wrong. TEMPERATURE CALIBRATION PROCEDURE (for technical personnel only) The meter is factory calibrated for temperature. [. . . ] Immerse the tip (4 cm /1½") in the sample and stir gently for approximately 30 seconds. For a faster response and to avoid cross contamination of the samples, rinse the electrode tip with a few drops of the solution to be tested, before taking measurements. TROUBLESHOOTING Evaluate the performance of your electrode based on the following possibilities: · Noise (readings fluctuate up and down) could be due to: - Clogged/Dirty Junction: refer to the Cleaning Procedure above. - Loss of shielding due to low electrolyte level (in refillable electrodes only): refill with fresh HI 7071 for single junction electrodes, or HI 7082 for double junction electrodes. 33 STORAGE To minimize clogging and ensure a quick response time, the glass bulb and the junction should be kept always moist and not allowed to dry out. 32 · Dry Membrane/Junction: soak in HI 70300 storage solution for at least 1 hour. · Drifting: Soak the electrode tip in warm HI 7082 solution for one hour, then flush the tip with distilled water. [. . . ]