User manual HANNA INSTRUMENTS HI 22

[. . . ] HI 21 & HI 22 Series Wall-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. [. . . ] The meters are equipped with a stability indicator. The user is also guided with indications on the display during the calibration procedure. Initial Preparation Pour small quantities of pH 7. 01 (HI 7007) and pH 4. 01 (HI 7004) and/or pH 10. 01 (HI 7010) solutions into individual beakers. If possible, use plastic beakers to minimize any EMC interference. HI 7004 HI 04 70 The items in the Data field are separated by blanks. 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. HI 7007 SETTING THE BAUD RATE The transmission speed (baud rate) of the meter and external device must be the 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 (#5 page 7) with the Connection for Electrode Reference (#6 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). · pH 7. 01 is the default value for the 1st calibration buffer. 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. [. . . ] New reference material is constantly being added to the library. For these and others catalogs, handbooks and leaflets, contact your dealer or the nearest Hanna Customer Service Center. To find the Hanna Office in your vicinity, check our home page at www. hannainst. com Recommendations for Users Before using these products, make sure that they are entirely suitable for the environment in which they are used. Operation of these instruments in residential areas could cause unacceptable interferences to radio and TV equipment. [. . . ]