User manual HANNA INSTRUMENTS BL 7917

[. . . ] Instruction Manual BL 7916 - BL 7917 pH and ORP Controller & Dosing Pump http://www. hannainst. com These Instruments are in Compliance with the CE Directives Dear Customer, Thank you for choosing a Hanna product. Please read this instruction manual carefully before using the pump. This manual will provide you with the necessary information for a correct use of the pump, 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 contact available on the terminals can be normally open or closed. It can be used as a switch to drive an external mixer when the pump is dosing, or can activate an auxiliary pump or any other device. With BL 7916, the contact can be selected to remain open when the pH value is within the set limits (the pump is not dosing) and closed when the pump is dosing or viceversa. By shorting the Common (middle) terminal with the NO or NC terminal on the driving circuit inside the controller section, a normally open or a normally closed state can be achieved, as shown below: ALARM CONTACT If the reading drifts from the setpoint by more than ±2. 00 pH in BL 7916 and ±200 mV in BL7917, an external alarm can be activated. The contact is rated at 2 amps at 220VAC. No power is supplied through the system and it is an open/closed contact only. With BL 7916, the contact can be selected to be closed when the alarm is activated and open when the alarm is off or viceversa. Short the middle terminal located on the driving circuit inside the controller section with the NO or NC terminal (see above). 4-20 mA ISOLATED OUTPUT A 4-20 mA proportional output is available in these connections: 4 mA=0 pH; 20 mA=14 pH (BL 7916) and 4 mA=-999 mV; 20 mA=+999 mV (BL 7917). The output is optically isolated. 20 SETPOINT ADJUSTMENTS · Move the display selector switch to SET. · With a small screwdriver adjust the SET COARSE trimmer to display a value close to the desired setpoint e. g. 7. 00. · Adjust the SET FINE trimmer to display the exact setpoint value. · Once the desired setpoint is achieved, move the display selector switch back to MEASURE. ACID OR BASE SELECTION (BL 7916 only) If an acid chemical is to be dosed, move the ACID/BASE switch to ACID. This means that the pump will dose when pH measurements are higher than the setpoint. If an alkaline chemical is to be dosed, move the ACID/BASE switch to BASE. This means that the pump will dose when pH measurements are lower than the setpoint. REDUCING OR OXIDIZING SELECTION (BL 7917 only) If a reducing chemical is to be dosed, move the RED. /OXID. This means that the pump will dose when redox measurements are higher than the setpoint. If an oxidizing chemical is to be dosed, move the RED. /OXID. This means that the pump will dose when the redox measurements are lower than the setpoint. The wires and cables needed for all connections can be fed through the two cable fittings located below the terminals. It is important to attach these cables properly because pump vibrations could loosen them. Replace the transparent cover and fasten the screws. 21 p H CALIBRATION BL 7916 only: · Ensure that the display selector switch is set to MEASURE and dip the electrode tip in a neutral buffer solution (pH 7. 01). · Adjust the OFFSET trimmer to display 7. 01 on the LCD. · Rinse the electrode with clean water and dip the electrode tip in pH 4. 01 (acidic) or pH 10. 01 (alkaline) buffer solution. · Adjust the slope trimmer to read 4. 01 or 10. 01 on the LCD. The slope calibration with pH 4. 01 buffer is suggested if the controller will be used for acid measurements or pH values below 7, pH 10. 01 is in turn recommended for alkaline measurements or pH values above 7. 22 TROUBLESH OOTING GUIDE ELECTRICAL The pump does not operate when turned ON: · Check the power supply and connections. Voltage should be between 100 - 130 VAC for 115 V models and between 200 - 250VAC for 230 V models. [. . . ] In the event that measurements are performed with solutions containing sulfides or proteins, the cleaning of the diaphragm of the reference electrode must be performed more often. In order to have a correct functioning of the ORP electrode, immerse it into HI 7020 and measure the response; the obtained value should be within 200 and 275 mV. After this functional test, it is suggested to wash the electrode thoroughly with water and proceed to the oxidizing or reducing pretreatment before taking measurements. When not in use, the electrode tip should be kept moist and far from any type of mechanical stress which might cause damage. [. . . ]