User manual HANNA INSTRUMENTS HI 8614L

[. . . ] Instruction Manual HI 8614 - HI 8614L HI 8615 - HI 8615L pH and ORP Transmitters pH pH INDIC ITTER SM & TRAN L HI 8614OR AT These Instruments are in Compliance with the CE Directives http://www. hannainst. com 1 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 instrument, as well as a precise idea of its versatility in a wide range of applications. These instruments are in compliance with the directives. TABLE OF CONTENTS Preliminary Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] If routine check is required, the following procedures shall be performed. · Follow the procedure at page 7 to perform calibration on the transmitter module (using a ammeter). Simulate a 4. 00 mA loop current for the transmitter (i. e. pH 0. 00 as Electrode input) and check for display reading. Simulate a 20. 00 mA loop current for the transmitter (i. e. pH 14. 00 as Electrode input) and check for display reading. · · Note: when the instrument is used in conjunction with the Hanna indicator HI 8510T or controllers HI 8710T, HI 8711T, the calibration can also be performed on the indicator/controller. In this case slight calibration adjustment can be made on the indicator/ controller even if the whole system calibration is advised, always starting from the transmitter. 12 pH CALIBRATION WITH FIXED TEMPERATURE COMPENSATION (HI 8614 & HI 8614L only) · Take the temperature of the buffer solutions using a Checktemp or a thermometer with a resolution of at least 1°. Connect the appropriate resistor to the "TEMP. PROBE" terminals (see page 6) depending on the temperature of the calibration solution. Follow the procedure as outlined in the calibration with automatic temperature compensation and use the thermometer reading to adjust the trimmer until the ammeter reads the value according to the following table. 4. 01 pH Buffer 7. 01 pH Buffer 10. 01 pH Buffer °C · · Temperature °C 0 5 10 15 20 25 30 35 40 45 50 55 60 °F 32 41 50 59 68 77 86 95 104 113 122 131 140 pH 4. 01 4. 00 4. 00 4. 00 4. 00 4. 01 4. 02 4. 03 4. 04 4. 05 4. 06 4. 07 4. 09 mA 8. 576 8. 565 8. 565 8. 565 8. 565 8. 576 8. 587 8. 599 8. 610 8. 622 8. 633 8. 645 8. 667 pH 7. 13 7. 10 7. 07 7. 04 7. 03 7. 01 7. 00 6. 99 6. 98 6. 98 6. 98 6. 98 6. 98 mA 12. 137 12. 103 12. 069 12. 034 12. 023 12. 000 11. 989 11. 977 11. 966 11. 966 11. 966 11. 966 11. 966 pH 10. 32 10. 24 10. 18 10. 12 10. 06 10. 01 9. 96 9. 92 9. 88 9. 85 9. 82 9. 79 9. 77 mA 15. 789 15. 697 15. 629 15. 560 15. 491 15. 434 15. 377 15. 331 15. 285 15. 251 15. 217 15. 182 15. 159 13 ORP CALIBRATION (HI8615 & HI8615L) Initial preparation: Disconnect the +ve supply cable from the "+VE LOOP" terminal and connect a 20 mA f. s. ammeter between the +ve cable and the "+VE LOOP" terminal. With HI 8615L the instrument display can be used during calibration without the need to connect the ammeter. In this case the values are directly expressed in mV units. Pour a small quantity of HI 7020 ORP solution into a beaker. Procedure: · Connect the shorting BNC connector to the ORP transmitter. · Adjust the OFFSET ADJUSTMENT trimmer on the module for a display of 12 mA on the ammeter or 0 mV on the instrument display (HI 8615L only). This sets the zero point for the transmitter. 20 70 HI SLOPE ADJUSTMENT OFFSET ADJUSTMENT mA · Connect the ORP electrode to the transmitter and immerse the tip of the electrode into a beaker of HI 7020 ORP calibration solution, and check that the ammeter reading lies between 13. 6 and 14. 2 mA or the instrument reading is between 200 and 275 mV at 25°C (HI 8615L). mA HI 7020 14 If the reading lies outside this range, adjust the slope adjustment trimmer on the transmitter for a reading just within this range. The unit is now calibrated. · SLOPE ADJUSTMENT OFFSET ADJUSTMENT A complete calibration of the transmitter module is advised periodically. This calibration procedure requires the HI 8427 or the HI 931001 pH and ORP simulator to simulate the ORP electrode. HI 8427 or HI 931001 produce a known signal into the system so that the faults of the system can be isolated. DO NOT BE ALARMED IF ANY SALT DEPOSITS ARE PRESENT. This is normal with electrodes and they will disappear when rinsed with water. [. . . ] It takes longer time for the reading to stabilize if the resistance is higher. In addition, the response time will suffer to a greater degree at temperatures below 10°C. 2x109 -10 1x109 -10 -10 2x108 1x108 -10 2x107 -10 1x107 -10 -20 -20 0 +10+20 +30+40 +50+60+70 +80+90 ° C Since the resistance of the pH electrode is in the range of 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 for a stable pH reading. The pH electrode's life also depends on the temperature. If constantly used at high temperatures, the electrode life is drastically reduced. 23 Typical Electrode Life Ambient Temperature 1- 3 years 90 °C Less than 4 months 120°C Less than 1 month High concentrations of sodium ions interfere with readings in alkaline solutions; the pH at which the interference starts to be significant depends upon the composition of the glass. [. . . ]