Hanna Instruments HI 98240 Instruction Manual

Contents

Hanna Instruments HI 98240 Instruction Manual Manual pdf 13 page image

2524GOOD LABORATORY PRACTICE (GLP)GLP is a set of functions that allows the storage or retrieval (whennecessary) of data regarding the maintenance and status of theelectrode. The pH electrodes have a built-in EEPROM in whichcalibration data are read at start-up and stored after calibration.HI98230 and HI98240 can automatically analyze the data andadvise the user if a problem is found with a clear message.PROBE LIFE VERIFICATIONAt the end of calibration, the meter checks if offset is between -30 and+30mV and the slope between 53.5 and 62 mV/pH. If the values arenot within these parameters, the message "old probe" scrolls across theLCD and the symbol ** is reported in the Last Calibration Data. Theelectrode is still working, but it will be necessary to perform a cleaningprocedure (see electrode cleaning and maintenance paragraph) orreplace it.If the offset is outside the -60 and +60 mV range, the "dead probe"message will scroll across the LCD and the symbol -- is reported inthe Last Calibration Data. The readings will blink to warn the userthat they are not reliable.LAST CALIBRATION DATALast calibration data are stored automatically after a successfulcalibration. Data can be displayed or printed through the appropri-ate setup codes (10 to display pH data; 11 to display mV data; 12to print pH and mV data); mV data are available in HI98240 only.ELECTRODE IDENTIFICATIONAt start-up the meter checks if the electrode is inserted. If not themessage "no probe" scrolls across the LCD and a dashed line will bedisplay in place of the reading. Each printout will have a "◊" symbolon the pH line.If the meter detects a "dead probe" the reading will blink.The meter checks the electrode only at start up. If an electrodereplacement is needed, turn the meter off before disconnecting theelectrode. Then replace the electrode and turn the meter on again.CALIBRATION ALARM TIME-OUTThe calibration alarm time-out is available only for pH calibration.It is possible to set (through setup code 13) the number of daysbefore the next required calibration procedure. User can set a valuefrom 00 (disabled) to 99 days. The default value is 00."Stor log" and the value will be stored in the lot 00 (log on demanddata area). If the printing function is enabled, a printout is alsoproduced providing the following information:a - Dateb - Sample numberc - Timed - ReadingsNote: When the Log on demand data area is full and the LOG keyis pressed, the sample will not be stored and the LCD willdisplay "FULL". In this case it is necessary to delete the Log ondemand data to proceed.TO RETRIEVE LOGGED DATALogged data stored in the EEPROM can be viewed on LCD or printed.HI98230 and HI98240 also allow the downloading of logged data toPC for reproduction, storage and elaboration (e.g. graph drawing).To view or print logged data see "TO SCAN LOGGED DATA" on page 11.To download data to PC see "DATA TRANSFER TO PC" on page 27.OTHER FEATURESLCD BACKLIGHTThe LCD can be illuminated to allow the user to see the readings evenin dark environments. This feature can be enabled/disabled pressingthe ALT and LIGHT keys.If the LCD backlight feature is enabled, the LCD remains illuminateduntil the feature is disabled pressing the ALT and LIGHT keys. TheLCD backlight can be disabled in order to save power and it isautomatically disabled when batteries are in low battery condition.Note: When an external power supply is connected to the instru-ment, the backlight is not automatically enabled.Note: When LOBAT appears on LCD it is not possible to enablebacklight. If the user attempts to enable the LCD backlight inlow battery condition, the meter will show "bAtt" on LCD.Real Time Clock (RTC)The instrument has an internal Real Time Clock (RTC) circuit with abackup lithium battery. This allows the meter to update time anddate even when both batteries and external power adapter aredisconnected.