CONTENTS TITLE SECTION PAGES I GENERAL INFORMATION l-l II SPEICIFCATIONS 2-1, 2-2 III THEORY OF OPERATION 3-1, 3-2,3-3,3-4 IV INSTALLATION 4-1, 4-2,4-3 V CALIBRATION AS A: 5-1, 5-2,5-3,5-4 5-5 HI HI LO PUMP LO ALARM HI ALARM LO ALARM CONTROL VI MISCELLANEOUS 6-l VII MAINTENANCE AND OVERHAUL 7-l DRAWINGS FIG. 1 OUTLINE AND MOUNTING DIMENSIONS FIG. 2 TRANSDUCER INSTALLATION FIG. 3 EASILY AVOIDABLE INSTALLATION ERRORS FIG. 4 OUTLINE AND CABLE CONNECTION DIAGRAM FIG. 5 FIG.
I. GENERAL INFORMATION The Milltronics Level Genie Ultrasonic System is an entirely "Solid State Package", designed to provide contact closure at accurately determined levels of liquids and solids up to 10 feet (3M) from the transducer. This system consists of only two elements, ultrasonic transducer and cabineted electronics, neither of which require contact with the material to be measured. Seperation between transducer and electronics may reach 600 feet (183M).
II. SPECIFICATIONS Power Required 115 VAC + 10% 40 Hz at 6VA Transducer Barium Titanate element C.P.V.C. outer housing and polyurethane radiating face. Optional face materials are available. Transducer rated for Class I, Groups A, B, C, D, &'Class II Groups F & G. Range 1.5 to 10.0 feet 0.45 to 3.1 meters output Two (2) Form C, S.P.D.T. contacts rated 10A 115VAC non-inductive Set Points Two (2) independently adjustable throughout the range Set Point Hysterisis 0.5 inch per ft.
Operating Modes* 1. 2. 3. 4. Enclosure Nema 12 standard Nema 4 optional Weight Transducer - 2 lbs. Pump up/down Hi-Lo alarm Hi-Hi alarm Lo-Lo alarm One programming module supplied with unit. Additional modules available as options. Enclosure & Electronics - 12 lbs.
III. THEORY OF OPERATION TRANSCEIVER CIRCUITRY 1. General Description The transceiver uses a single tuning section which is time-shared between the transmitting and receiving functions. Three co-ordinatinq signals, generated in conjunction with the repetition rate signal, control the transceiver switching it between transmitting and receiving modes. 2. As a Receiver Echo signals, generated when an echo strikes the face of the transducer, are presented to the receiver input via R1.
Q6 and Q7 provide additional amplification. Q7 also serves as a detector charging C9 with the positive halfcycles of the received signal. Q8 is turned on during the blanking period to prevent C9 from accumulating any charge. Thereby precluding any receiver output during this time period, When the voltage on C9 reaches about 1 volt, Q9 turns on and the voltage at the collector of Q9 falls to zero signifying reception of an echo.
ECHO PROCESSING LOGIC 1. General Description The digital echo processor establishes the necessary timing and limit functions. Coincidently, statistical techniques are employed to discriminate against response to spurious noise inputs. 2. Timing & Limit Generation IC 3-1, IC 3-2 and IC l-l form a typical hybrid monstable multivibrator. This type of pulse generator is extremely stable over a wide range of temperature and/or bus variations.
4. Digital Echo Processing Various digital, statistically based, processing techniques are employed to render the Level Genie immune to random noise inputs. a. Echo width detection ignores short duration signals such as line transients and most SCR noise. b. Echo reception logic accepts only one echo per transmit sequence. C. d. Digital windows are established at the"NEAR'and 'FAR'setpoints and only echoes occurring in these zones are recognized.
IV. 1. INSTALLATION Electronic Package The electronic circuits of the Level Genie Ultrasonic Level Switch are contained on a single printed circuit motherboard. A Nema 12 enclosure is supplied. Refer to Fig. 1 for outline and mounting dimensions. Separate 1/2" conduits should be installed for the power wiring and the transducer cable. The transducer cable must not be installed in a conduit with other wiring. Fig. 3 indicates proper terminal connections for the electronics.
5. Alarm Anti-Latch Circuit (stab select at A position) In some applications, the Level Genie is used to detect an object instead of a material level. Usually, a HIGH-HIGH program module can be used: HIGH alarm to detect the object and in the absence of the object, echoes received from any target out of HIGH alarm zone will reset the system. However, if there is no target to intersect the ultrasonic beam within 10 feet (the maximum range of the Level Genie), no echo will be received.
disable the alarm time delays while calibrating. The "10 ft. - 5 ft.'" toggle should be in the appropriate position reflecting the desired operating range. 3. Transducer The ST25 series transducers have an outer housing of chlorinated polyvinyl chloride (CPVC) and a radiating face of polyurethane. These materials have excellent resistance to a wide range of corrosives but may be damaged by ketones, aromatics and some chlorinated hydrocarbons. Alternate materials are available for these environments.
within the vessel such as a supporting beam which would interfere with the sound path between the transducer and the material being measured. NOTE Ultrasonic sound waves are radiated from the face of the Transducer within a cone of approximately 8 degrees. The Level Genie System depends upon these sound waves reaching the surface of the material to be measured and being reflected back along this same "sound path".
V. CALIBRATION Before applying line power to the Level Genie, ensure that all pre-start-up checks (Section IV) have been completed. 1. General Alarm Calibration It is usually expedient to calibrate the Level Genie before installation, thereby avoiding the necessity of changing bin levels to set the trip points. After installation a spare transducer serves as an invaluable tool for checking calibration. a. b. c. d.
SPECIFIC CALIBRATION OF HI-HI PROGRAM MODULE (OMIT IF OTHER PROGRAM USED) 9. With the transducer placed at a distance from a fixed target representative of the high level, farthest from the transducer, adjust the "FAR" potentiometer counter clockwise until LED2 comes on. Then turn the control slowly clockwise until LED 2 extinguishes (Relay 2 drops out). h. Set the higher of the two high alarm points as follows.
a delay in output response by 3 seconds or 10 seconds depending on the position of the delay toggle. I M P O R T A N T Rotating the"NEAR"and"FAR"setpoints in the direction of the arrows (on the PCB) brings the trip points closer together. Caution must be exercised not to cross these controls. The NEAR setpoint should always be set to a higher level than the FAR setpoint.
2. Pump Up/Down Program Module - - - r Actuation In "pump down" operation, the liquid level must rise above the NEAR setpoint to de-energize the relays. Once this condition is met they are locked in the de-energized state, until the level drops below the FAR setpoint. Thus, rising above the near setpoint sets the control state until a low or far level is achieved.
c. a. e. f. Set the "NEAR" potentiometer 1/4 turn from fully counter clockwise. Set the "FAR" potentiometer fully clockwise. This sets the trip point at maximum range. Move the transducer toward the target until the LED indicators extinguish (relays dropped out). Then, with the distance between the transducer and target corresponding to the desired low level, adjust the "FAR" setpoint, slowly counter clockwise until the LED indicators illuminate (relays energized). The lower pump limit is now established.
VI. MISCELLANEOUS Checks to make before pushing the Panic Button SYMPTOM Unable to calibrate one setpoint CAUSE Program module offset in socket or inverted. High Alarm apparently inoperative 'NEAR'setpoint set too close to minimum range or within blanking range.
VII. MAINTENANCE This equipment requires very little maintenance due to its solid-state circuitry. However, a program of periodic preventive maintenance should be initiated. This should include regular inspection, general cleaning, transducer face inspection, overall system performance checks, and standard good-housekeeping practices. A periodic inspection of the transducer is recommended in some applications, at which time any build-up of material on the transducer face should be removed.
FIG-1 OUTLINE & MOUNTING DIAGRAM
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FIG:3 EASILY AVOIDABLE INSTALLATION ERRORS.
a company to be controlled by Throughout the world Milltronics has become a name respected for the high quality of its industrial process controls. The engineering and design capabilities that produce our product line are among the best to be found. You need only look at the rapidly growing involvement of our company, at the preliminary engineering and design stages of new plants as well as major plant revamps to realize the growing importance of our product line.
