RU2156446C2 - System for remote measurement of level of liquid - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: invention is related to ultrasonic systems with solid waveguide measuring level of liquid. It incorporates ultrasonic converter of liquid level connected to pulse generator, amplifier, communication channel, secondary device, threshold unit, delay element, logic OR gate and power supply stabilizer. Communication channel comes in the form of one pair of wires connecting secondary device to output of amplifier, input of power supply stabilizer and input of threshold unit which output is connected to input of delay element. Output of the latter is connected to first input of logic OR gate and to input of pulse generator whose output is connected to input of ultrasonic converter of level of liquid. Its output is connected to second input of logic OR gate which output is linked to input of amplifier whose power supply input is connected to output of power supply stabilizer. EFFECT: decreased number of wires in communication channel, reduced expenses for realization of system and expanded functional capabilities of system. 1 cl, 2 dwg

Description

 The invention relates to ultrasonic level measuring systems with a solid waveguide and can be used for remote measurement of liquid levels in tank farms for storing petroleum products.

 A known liquid level measurement system (A.S. N 838381, IPC G 01 F 23/28, 1981), comprising an ultrasonic liquid level transducer, a pulse generator, an amplifier, a communication channel and a secondary device is a crucial unit.

 The disadvantage of this system is the need for several (more than two) communication lines between liquid level transducers that are remote from each other and a secondary device, since in remote measurement systems the costs of communication lines make up a significant part of the total cost.

 Closest to the claimed system is a remote level measurement system (RU-PT2 Level Gauge, Technical Description 4B1.430.513TO, 1994), containing an ultrasonic (electromechanical) liquid level transducer, pulse generator, amplifier, communication channel, and a secondary device.

 The disadvantage of this system of remote measurement of liquid level is the multi-conductivity of the communication channel.

 In addition, the use of such a secondary device for one measuring channel reduces its functionality.

 The objective of the invention is to reduce the number of wires in the communication channel.

 The implementation of the invention will reduce the cost of implementing the system and expand its functionality.

 This is achieved by the fact that a threshold device, a delay element, an OR logic circuit and a power regulator are additionally introduced into the remote liquid level measurement system containing an ultrasonic liquid level transducer connected to a pulse generator, an amplifier, a communication channel, and a secondary device, and the channel the connection is made in the form of one pair of wires connecting the secondary device with the output of the amplifier, the input of the power stabilizer and the input of the threshold device, the output of which is connected to the input of the delay element, in the path of which is connected to the first input of the OR circuit and to the input of the pulse generator, the output of which is connected to the input of the ultrasonic liquid level transducer, the output of which is connected to the second input of the OR circuit, the output of which is connected to the input of the amplifier, whose power input connected to the output of the power regulator.

 In addition, the secondary device contains a commutator of communication channels connected to the data exchange bus with a microprocessor controller, and the N-switched inputs and outputs of the commutator of communication channels are the "inputs / outputs" of the secondary device for connecting to communication channels.

 In FIG. 1 is a structural diagram of a system; FIG. 2 - diagrams of signals.

 The remote liquid level measurement system comprises an ultrasonic liquid level transducer 1, a pulse generator 2, a delay element 3, an OR logic 4, wherein the ultrasonic liquid level transducer 1 is connected to a pulse generator 2, which is connected to a delay element 3 connected to a logic circuit "OR" 4. In addition, the system includes a threshold device 5, an amplifier 6, a power regulator 7, a communication channel 8 in the form of one pair of wires, a secondary device 9. The input of the delay element 3 is connected to a threshold device oystvom 5 having an input, the output of the amplifier 6 and the voltage regulator 7 through the input communication channel 8 connected to the secondary device 9 which comprises a switch 10 communication channels with N-switched "input-output", the data exchange bus 11 and the microprocessor controller 12.

 The system operates as follows.

 In working condition from the secondary device 9 through a pair of wires of the communication channel 8 to the inputs of the power stabilizer 7 and the threshold device 5 receives the supply voltage.

 In accordance with the level measurement program, the microprocessor controller 12 issues a start command signal (see FIG. 2) to the communication channel switch 10 through the data exchange bus 11. The latter forms a signal in the wires of the communication channel 8 in the form of a sharp decrease in the supply voltage. This signal is perceived by the threshold device 5, which in turn provides a signal to the delay element 3, which after a predetermined time interval passes this signal to the inputs of the pulse generator 2 and the logic circuit "OR" 4. From the output of the latter, the signal goes to the input of the amplifier 6 and, amplified in it, is sent through the wires of the communication channel 8 to the secondary device 9. This signal at the output of the amplifier 6 has the form of a pulsed decrease in the supply voltage, but at a level lower than the start command signal sent from the secondary device 9 (with . Fig. 2). Therefore, it does not pass through the threshold device 5 to the delay element 3, but is recorded only by the microprocessor controller 12 of the secondary device 9, as a signal of the beginning of a level measurement cycle. The time delay on the delay element 3 is set so as to ensure the attenuation of interference from wave processes in the wires of the communication channel 8, caused by the start command signal at the time of passage of the signal to start the measurement cycle.

 The signal from the output of the delay element 3 goes to the input of the pulse generator 2. The latter generates a high-voltage pulse at its output, which is fed to the input of the ultrasonic transducer of the liquid level 1.

 After a time interval proportional to the value of the liquid level, an pulse signal appears at the output of the ultrasonic liquid level transducer 1, which, passing through the "OR" 4 logic circuit, is fed to the input of amplifier 6 and amplified in it to a level similar to the signal level at the beginning of the cycle measurement, is fed through the wires of the communication channel 8 to the secondary device 9, in which it is recorded by the microprocessor controller 12 as a signal for the end of the measurement cycle.

 Stabilization of the supply voltage for the amplifier 6 during the passage of command and measuring signals through two common wires of the communication channel 8 provides a power stabilizer 7.

 The foregoing measurement cycle is repeated several times and, based on the average value of the time intervals obtained from the ultrasonic liquid level transducer, the microprocessor controller 12 performs calculation and indication of the liquid level. Thus, the use of a threshold device 5, a delay element 3, an "OR" 4 logic circuit, and a power supply stabilizer 7 in the system made it possible to reduce the number of wires of the communication channel 8 and, therefore, reduce the cost of implementing the system.

 The secondary device 9 of the proposed system can be used for a multi-channel system for measuring the liquid level due to the presence of a commutator 10 of communication channels, which also functions as an identifier for commands of a microprocessor controller 12, a driver of input information signals by level and shape, and a power function for a remote liquid level measuring system.

Claims (2)

 1. A remote liquid level measurement system comprising an ultrasonic liquid level transducer connected to a pulse generator, an amplifier, a communication channel and a secondary device, characterized in that a threshold device, a delay element, an OR logic circuit and a power stabilizer are additionally introduced into it, and the channel the connection is made in the form of one pair of wires connecting the secondary device with the output of the amplifier, the input of the power stabilizer and the input of the threshold device, the output of which is connected to the input of the delay element, the output of which is connected to the first input of the OR logic circuit and to the input of the pulse generator, the output of which is connected to the input of the ultrasonic liquid level transducer, the output of which is connected to the second input of the OR logic circuit, the output of which is connected to the input of the amplifier, the input of which is connected to the output of the stabilizer nutrition.  2. The system according to claim 1, characterized in that the secondary device comprises a commutator of communication channels connected by a data bus with a microprocessor controller, and N switched inputs and outputs of a commutator of communication channels are inputs and outputs of a secondary device for connecting to communication channels.

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