User manual HANNA INSTRUMENTS BL 931700

[. . . ] Damages due to accident, misuse, tampering or lack of prescribed maintenance are not covered. If service is required, contact the dealer from whom you purchased the instrument. If under warranty, report the model number, date of purchase, serial number and the nature of the failure. If the repair is not covered by the warranty, you will be notified of the charges incurred. [. . . ] Two models are available: · BL 931700-0 powered at 12 Vdc · BL 931700-1 powered at 115 or 230 Vac ASSEMBLING VIEW FUNCTIONAL DESCRIPTION Front panel Rear panel OPERATIONS REAR PANEL CONNECTIONS Terminals #1, #2 and #3: Electrode · Connect a pH-electrode to the meter BNC plug (#1). · To benefit from the differential input, connect the proper electrode wire (if available) or a cable with a potential matching pin (grounding bar) to the relevant terminal (#3) on the rear panel. Note: When the Matching Pin can not be immersed together with the pH electrode in the solution, disable the differential input by shorting terminals #3 (Matching Pin) and #2 (Electrode Reference) with a jumper wire. Terminals #4: Dosing selection · For acid dosage, leave the circuit open. · For alkaline dosage, short the terminals with a jumper wire. Terminals #5: 4-20 mA Output · These output terminals are used for connecting a recorder. The output is from 4 to 20 mA and is proportional to the measured pH value. Terminals #6: Power Supply · Model BL931700-0: connect the 2 wires of a 12 Vdc power adapter to the terminals +12 Vdc and GND. · Model BL931700-1: connect a 3-wire power cable to the terminals while paying attention to the correct earth (PE), line (L) and neutral (N1 for 115 V or N2 for 230 V) contacts. Terminals #7: Dosing Contact · This contact drives the dosing system, accordingly to the selected setpoint and dosing direction: · if "Acid" dosage is set, the relay is ON and dosing activated if measured value is higher than setpoint; · if "Alk" dosage is set, the relay is ON and dosing activated if measured value is lower than setpoint. Note: The setpoint has a typical hysteresis value comparable to the meter accuracy. Terminals #8: External Disabling Contact · This is a normally open contact and can be used for example for connecting a level controller. · When the contact is closed, any dosing action stops, the LED indicator on the front panel will blink Red and the LCD will show the "HALT" warning message. Note: If the OFF/Auto/ON switch is in ON position, the dosing action will not stop, even if the external disablig contact is closed. Switch for selecting dosing mode: · OFF = dosing disabled · Auto = automatic dosage, depending on setpoint value and dosing selection · ON = dosing always active 3. "MEAS" key to set the instrument to measurement mode 4. "SET" key to display and set the setpoint value 5. "SET" trimmer to adjust the setpoint value (0 to 14 pH) 6. "SLOPE" trimmer to adjust the pH slope value during calibration 7. "OFFSET" trimmer to adjust the pH offset value during calibration 8. [. . . ] Install or immerse the electrode in the solution to be monitored, then press the "MEAS" key (if necessary). The LED indicator will light up Green when the meter is in measurement mode and dosing is not active, while will light up Orange/Yellow for signaling that a dosing action is in progress. CALIBRATION With meter in measurement mode, immerse electrode and Matching Pin (if available) in pH 7. 01 buffer solution, shake briefly and wait for reading to stabilize. Adjust the OFFSET trimmer until "7. 01 pH" is displayed on the LCD. [. . . ]