Hanna Instruments pH 211R Instruction Manual

Contents

Hanna Instruments pH 211R Instruction Manual Manual pdf 5 page image

98• Switch the meter on and press the RANGEkey to enter the mV mode.• Submerge the ORP electrode tip (4 cm /1½") into the sample. Allow a few minutesfor the reading to stabilize.• The meter displays the mV reading on the primary LCD.• If reading is out of range, "---" will appear on the LCD.TAKING TEMPERATURE MEASUREMENTSConnect the HI 7669/2W temperature probeto the proper socket on the rear panel andturn the instrument on. Dip the temperatureprobe in the sample and allow the reading tostabilize.HOLD FUNCTIONPress and hold the MEM key. The last reading will be frozen on thedisplay until MEM is released. During this operation, the MEMindicator is also shown on the LCD.Press MR to recall the previously memorizedreading. The value will be displayed with theMEM indicator on the LCD.4 cm(1½")OUTPUT RECORDER FUNCTIONConnect the recorder to the analog output socket and turn theinstrument ON. The value on the analog output will be related withthe pH or mV value displayed on the LCD as follows:pH: 0 7 14mV: -2000 0 2000analog output: 0 V 2.5 V 5 VRESETThe RESET button (#14 on page 4) should only be used when theinstrument displays erroneous messages due to strong electrical inter-ference or when the power supply was disconnected before switchingthe meter off.After pressing RESET, always recelibrate the unit before proceeding.pH CALIBRATIONFrequent calibration is recommended. Moreover, the instrument shouldbe re-calibrated for pH:a) whenever the pH electrode is replacedb) at least once a weekc) after testing aggressive chemicalsd) if higher accuracy is requirede) after the RESET button has been pressedPREPARATIONPour small quantities of the buffer solutions into clean beakers. Ifpossible use plastic beakers to minimize any EMC interferences.For accurate calibration and to minimize cross contamination use twobeakers for each buffer solution. One for rinsing the electrode and thesecond for calibration.If you are measuring in the acid range, use pH 4.01 as secondbuffer; if you are measuring in the alkaline range, use pH 10.01 orpH 9.18 as second buffer.PROCEDUREFive memorized buffer values are available for calibration: pH 4.01,6.86, 7.01, 9.18 and 10.01.Calibration can be performed at 1 or 2 points. For best accuracy, a 2point calibration is recommended.