Hanna Instruments HI 98160 Instruction Manual

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Contents

13AUTO ENDPOINT MODEThe Auto Endpoint feature allows the user to freeze the display whena stable reading is reached.To enter the Auto Endpoint mode, press the ALT and AutoEnd keys.The MEM symbol will blink on the LCD until measurements becomestable, then readings (pH/mV and temperature) are frozen on thedisplay.By pressing the RANGE key it is possible to switch between pH andmV measurements.While in Auto Endpoint mode, frozen readings can be logged bypressing the LOG key (See "Logging function" section).To exit from Auto Endpoint mode, press again the CAL and AutoEndkeys. The meter will return to continuous measurement mode.Note: By entering the setup mode, by log consulting or by pressingthe ALT and GLP keys, the meter will automatically exit fromthe Auto Endpoint mode.pH CALIBRATION PROCEDUREFor greatest accuracy, it is recommended to calibrate the instrumentfrequently. For a faster procedure, it is possible to calibrate in 1 point,but it is always a good practice to calibrate in 2 points.A two-point calibration can use any combination from the followingsets of pH buffers:1.68 4.01 (6.86 or 7.01) (9.18 or 10.01) 12.45or3.00 (6.86 or 7.01) (9.18 or 10.01) 12.45E.g. in the case of a two-point calibration in the acidic range (from 0to 7 pH), use the pH 7.01 (or 6.86) buffer as first solution and pH4.01 as second one; if testing in the alkaline range (from 7 to 14pH), use the pH 10.01 (or 9.18) buffer as second solution.Due to electrode conditioning time, the electrode must be keptimmersed a few seconds to stabilize. The meter is equipped with astability indicator and the user will be guided step by step with easyindications on the LCD during the calibration. This will make thecalibration a simple and error-free procedure.20GOOD LABORATORY PRACTICE (GLP)Note: Press the ALT and DEL keys to escape without data deletion.When viewing through the logged data, the "NUL" message will bedisplayed when selecting a deleted sample.To delete all data in memory:ï Press the ALT and DEL keys while innormal operating mode. The "del All"message will appear on the LCD and the"CFM" indication will start blinking ask-ing for confirmation.ï Press the ALT and CFM keys to confirm deletion.Note: Press the ALT and DEL keys to escape without data deletion.Note: If no samples are stored in memory and a deletion isattempted, the meter will show the message "Zero" and thenreturns to normal operating mode.GLP is a set of functions that allows the storage or retrieval (whennecessary) of data regarding the maintenance and status of theelectrode.PROBE LIFE VERIFICATIONAt the end of calibration, the meter checks if offset is between -30 and+30 mV and the slope between 53.5 and 62 mV/pH. If the valuesare not within these boundaries, the message "old probe" scrolls acrossthe LCD. The electrode is still working, but it will be necessary to performa cleaning procedure (see electrode cleaning and maintenance sec-tion) or replace it.If the offset is outside the -60 and +60 mV range or the slope isoutside the 40 to 70 mV/pH interval, the "dead probe" message willscroll across the LCD; the readings will blink on the upper LCD to warnthe user that they are not reliable.CALIBRATION ALARM TIME-OUTThe calibration alarm time-out is available only for pH calibration.It is possible to set (through setup code "dUE") the number of daysbefore the next required calibration procedure. User can set a value

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