User manual HANNA INSTRUMENTS HI 8931 A-D

[. . . ] Instruction Manual HI 8931A/B/C/D HI 8936A/B/C/D HI 8936AL/BL/CL/DL HI 943500A/B/C/D Conductivity Process Instrumentation These Instruments are in Compliance with the CE Directives 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 correct use of the instruments, as well as a precise idea of thier versatility in a wide range of applications. These instruments are in compliance with the TABLE OF CONTENTS Preliminary Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] · Connect the 3-wire power cable to the 4-screw terminal strip according to the voltage level as indicated and pay particular attention to the correct live, earth and neutral terminal connections. 24 · The HI 8936 transmitter may be wallmounted at any convenient location close to the measurement site. To minimize thermal drifts due to extreme temperature fluctuations, particularly if the measurement is conducted outdoors, it is recommended that the transmitter is protected in a casing. · For the installation of the HI 7635 conductivity probe, it is necessary to use rubber seals between the probe and the pipe or elbow joints. When screwing on the joints, take care not to overtighten as excessive pressures can cause the probe to be damaged. · The conductivity probe HI 7635 is supplied with a 3m (10') length of cable. The six core cable from the probe is connected to the HI 8936 process conductivity transmitter as shown. See page 23 for the proper connection scheme. 25 · It is recommended that the HI 7635 is installed vertically. This is to ensure that trapped air bubbles or turbulent flows cause minimal interference to the measurement system. CAUTION: do not use in systems where temperature exceeds 80°C (176°F). · The HI7638 process conductivity probe is also supplied with a 3 m (10') length cable. The six core cable from this probe is connected to the HI 8936 process conductivity transmitter as shown. The 7-pin DIN connector has to be removed when this probe is used in conjunction with HI 8936 transmitter. See page 23 for the proper connection scheme. FOR HI 943500 ONLY Ensure that the HI7638 conductivity probe is connected to the meter securely by aligning the pins with the socket, pushing the plug in and tightening the threaded ring. 26 OPERATING INFORMATION The various parameters are set through the front panel keys and trimmers. When each key is pressed the corresponding LED is lit, indicating that the function is operational. Make sure that the conductivity meter, transmitter and probe are calibrated before using the instrument for measurements (see page 30 & 34 for HI 8931 & HI 8936 and page 38 for HI 943500). SET POINT To set the working point of the controller, press the SET key. The display will indicate the set value. Use a small screwdriver to adjust the trimmers COARSE and FINE until the desired set value is displayed. Above set-point control operation Leave the SET SELECT/COM connectors open. The set contacts relay will close if the measured value is higher than the set-point value and the SET ON LED will be lit. COM SET SELECT 27 Below set-point control operation Short the SET SELECT/COM connectors with a jumper wire. The set contact relay will close if the measured value is lower than the set-point value and the SET ON LED will be lit. COM SET SELECT ALARM Press the AL key and the display will show the set tolerance for the alarm. Use a small screwdriver to adjust the trimmer AL until the desired tolerance is displayed. Example: If the set value is 200 µS/cm and a Alarm of 50 µS/ cm is set, an alarm is activated every time the measured value is higher than 250 µS/cm or lower than 150 µS/cm. 28 When the alarm is active the ALARM LED is lit. The alarm contacts of HI 8931 and HI 943500 remain closed during normal operation. If the measured conductivity level is not within the tolerance of the set value, the alarm contact will be open. TAKING MEASUREMENTS WITH HI 8931 AND HI 943500 After setting the working point and alarm value, press the MEASURE key. The actual conductivity value of the test solution will be displayed. TAKING MEASUREMENTS WITH HI 8936AL, HI 8936BL, HI 8936CL, HI 8936DL The conductivity transmitters with LCD will always display the measurement value when connected to the HI 8931 controllers or a power supply. 29 CALIBRATION PROCEDURE OF HI8931 & HI8936 WITH HI7635 Material needed · HI 7635 conductivity probe · HI 8931 conductivity controller · HI 8936 conductivity transmitter · A 20 mA f. s. ammeter (for transmitters without LCD) · A reference conductivity meter with automatic temperature compensation accurately calibrated (e. g. HI 8733). PROCEDURE · Connect the HI 7635 probe to the HI 8936 transmitter (see page 23). [. . . ] If you prefer a reference temperature of 20°C (68°F), turn the SLOPE trimmer to display "11. 67 mS". 41 DIAGNOSTIC TESTS The HI 8931 and HI 943500 controllers are designed with built-in diagnostic functions to enable the user to check and troubleshoot the instrument. The checks performed are through the front panel keys and can be used to isolate the cause of malfunction. Press the MEASURE key before proceeding the following tests. A) Test Offset Press the TEST OFFSET key and the display should indicate the following values: HI 8931/HI 943500A HI 8931/HI 943500B HI 8931/HI 943500C HI 8931/HI 943500D 0. 0 mS 0. 00 mS 000 µS 0. 0 µS ±1. 0 mS ±0. 10 mS ±100 µS ±1. 0 µS 42 B) Test Slope Press the TEST SLOPE key and the display should indicate the following values: HI 8931/HI 943500A HI 8931/HI 943500B HI 8931/HI 943500C HI 8931/HI 943500D 100. 0 mS 10. 00 mS 1000 µS 100. 0 µS ±35. 0 mS ±3. 50 mS ±350 µS ±35. 0 µS Note: The reading obtained by these functions will vary if the OFFSET and the SLOPE trimmers on the front panel are adjusted. 43 INSTALLATION EXAMPLES Some typical installation setups are depicted in the following examples: Example #1 Example #2 44 Example #3 Example #4 Example #5 45 PROBE MAINTENANCE & CLEANING The probe can be compensated for normal contamination by a process of re-calibration. However, it is recommended that the process conductivity probe be removed from the system regularly for maintenance. For HI 7635 only: Deposits on the conductivity probe can be removed by immersing the probe in 0. 1 N Hydrochloric acid for about 30 minutes. [. . . ]