User manual HANNA INSTRUMENTS MV 602

[. . . ] pH 502 & mV 602 Series Panel-mounted, Microprocessor-based pH and ORP Controllers Instruction Manual Dear Customer, Thank you for choosing a Hanna Product. Please read this instruction manual carefully before using the instrument. It will provide you with the necessary information for the correct use of the instrument, as well as a precise idea of its versatility. If you need additional technical information, do not hesitate to e-mail us at tech@hannainst. com These instruments are in compliance with the directives. TABLE OF CONTENTS PRELIMINARY EXAMINATION . [. . . ] Buf 3 if only a two points calibration was performed) it is replaced by the "N" character. Note The "r485" message can appear on the LCD while the controller is receiving or answering commands. SETTING THE BAUD RATE The transmission speed (baud rate) of the meter and external device must be th same. To change this value, use setup item 71. 34 35 For accurate calibration, use two beakers for each buffer solution, the first one for rinsing the electrode, the second one for calibration. By doing this, contamination between the buffers is minimized. RINSE CALIBRATION · Remove the protective cap from the pH electrode and immerse it into the selected buffer solution (e. g. pH 7. 01) with the Potential Matching Pin and temperature probe, then stir gently. Note HI 7007 HI 7007 To obtain accurate readings, use pH 7. 01 and pH 4. 01 if you measure acidic samples, or pH 7. 01 and pH 10. 01 for alkaline measurements or perform a 3-point calibration for the entire range. One Point Calibration (Offset) · To perform the pH calibration enter the calibration mode, by pressing CAL and entering the password. · After the correct password is entered, the control actions stop and the primary LCD will display the pH value using the current offset and slope, with the "CAL" and " " indicators lit and the probe indicator " " blinking. The value displayed on the secondary LCD is the buffer value at the actual temperature. 1 The electrode should be submerged approximately 4 cm (1½") in the solution. The temperature probe should be located as close as possible to the pH electrode. When it is not possible to immerse the Potential Matching Pin together with the pH electrode in the solution, disable the differential input by connecting the Connection for Potential Matching Pin (#9 page 7) with the Connection for Electrode Reference (#8 on page 7) with a jumper wire. · Only when the reading is stable the probe indicator " " will stop flashing (after about 30 seconds) and the "CFM" indicator will start blinking. · Press CFM to confirm the calibration; if the reading is close to the selected buffer (±1. 5 pH), the meter stores the reading and the secondary LCD will display the expected second buffer value. Offset and slope calculation is made at the end by pressing CAL to exit. Note BUF Note The actual pH value varies with temperature, thus the calibration value displayed on the secondary LCD will vary around pH 4. 01, 7. 01 and 10. 01 with temperature changes: for example at 25 oC the display shows 4. 01 - 7. 01 - 10. 01, at 20 o C it shows 4. 00 - 7. 03 - 10. 06 (see page 57 for other values). If a different value is needed, select it on the secondary display by pressing or . If the reading is not close to the selected buffer, "WRONG " will blink. BUF · If CAL is pressed, the calibration process ends by memorizing a new offset value. The new offset value is stored and a default value of 57. 5 mV per pH unit at 25°C is assigned as the new slope value. For best accuracy however, it is recommended that a twopoint calibration is performed. Note If the wrong password is entered the system reverts back and restarts displaying the pH value. 36 37 Two-point Calibration · Proceed as described above for one-point calibration, using pH 7. 01 as the first point, but do not quit calibration by pressing CAL at the end. Three-point Calibration · Proceed as described above but do not quit calibration by pressing CAL. Note Note The meter will automatically skip the buffer that was used for the first calibration to prevent errors. · After the first calibration point is confirmed, immerse the pH electrode with the Potential Matching Pin into the second buffer (e. g. pH 4. 01) and stir gently The meter will automatically skip the two buffers that were used to prevent errors. · After the second calibration point is confirmed, immerse the pH electrode and the Potential Matching Pin into the third buffer solution (e. g. pH 10. 01) and stir gently. Note Note If you are not going to perform a three-point calibration, it is recommendable to use pH 4. 01 buffer if you are going to measure acid samples, or use pH 10. 01 buffer for alkaline samples. The electrode should be submerged approximately 4 cm (1½") in the solution. The temperature probe should be located as close as possible to the pH electrode. · Select the 2nd buffer value on the secondary display by pressing or (e. g. pH 4. 01). [. . . ] When not in use, the electrode tip should be kept moist and far from any type of mechanical stress which might cause damage. This can be achieved by installing the electrode in such a way that it is constantly in a well filled with the sample (stream or tank). When not in use, store the electrode with a few drops of HI 70300 storage solution in the protective cap. With industrial applications, it is always recommended to keep at least one spare electrode handy. [. . . ]