Ultrasonic transducer and current loop transmitter
First Claim
1. A remote ultrasonic sensor and control system comprising:
- at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal;
a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means; and
a current loop transmission means connecting said sensor means and central control means, said current loop transmission means including a first current loop continuously delivering the control signals to said sensor means as discrete current levels and a second current loop continuously delivering the electrical signal from said sensor means as a current level.
1 Assignment
0 Petitions
Accused Products
Abstract
Ultrasonic vibrations indicating trouble at remote locations are detected by sensors spaced in the vinicity of expected trouble. These sensors have weather resistant transducers that convert ultrasonic vibrations from a leak in a conduit, electrical arc, bearing vibration or the like, into an electrical signal. In the sensor there are circuits that amplify the electrical signal and transmit it with a current loop transmission system over a twisted pair of wires to a central control and analysis computer. The amplification of the signal at the sensor is controlled by a signal from the center computer which changes the gain increments until the sensor circuits are not saturated by the ultrasonic signal. This gain control signal is also delivered to the sensors over a twisted pair of wires by current loop transmission system.
-
Citations
22 Claims
-
1. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means; and a current loop transmission means connecting said sensor means and central control means, said current loop transmission means including a first current loop continuously delivering the control signals to said sensor means as discrete current levels and a second current loop continuously delivering the electrical signal from said sensor means as a current level. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means, the sensor means includes an ultrasonic transducer and a stepped gain amplifier whose gain is controlled by the control signal, the stepped gain amplifier has (i) an effective resistance in series with one end of the transducer and providing a signal from the transducer to the input of the amplifier, (ii) at least one series-connected resistance and switch connected between the input of the amplifier and the other end of the transducer, (iii) a source of at least one reference voltage; and
(iv) at least one comparator for comparing the control signal to the one reference voltage and for producing an output in response to the comparison, the output of said comparator controlling the actuation of the switch of said series-connected resistance and switch; anda current loop transmission means connecting said sensor means and central control means, said current loop transmission means delivering the control signals to said sensor means as discrete current levels and receiving the electrical signal from said sensor means as a current level. - View Dependent Claims (8, 9)
-
-
10. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means, the sensor means includes an ultrasonic transducer and a stepped gain amplifier whose gain is controlled by the control signal, the stepped gain amplifier has (i) a transistor connected with a first resistor and a second resistor, the output of the stepped amplifier being at the connection of the transistor to the first resistor, and the gain through said transistor being related to the ratio of the resistance values of the first and second resistances, (ii) at least one series-connected resistance and switch located in parallel with the second resistance, (iii) a source of at least one reference voltage, and (iv) at least one comparator for comparing the control signal to the one reference voltage and producing an output in response to the comparison, the output of said comparator controlling the activation of the switch of said series-connected resistance and switch; and a current loop transmission means connecting said sensor means and central control means, said current loop transmission means delivering the control signals to said sensor means as discrete current levels and receiving the electrical signal from said sensor means as a current level. - View Dependent Claims (11)
-
-
12. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal or the sensor means, the sensor means includes an ultrasonic transducer and a stepped gain amplifier whose gain is controlled by the control signal, the stepped amplifier is a field effect transistor with a drain resistor, a voltage applied to the drain resistor acting to control the gain of the amplifier, and means for varying the voltage applied to the drain resistor in response to changes in the control signal; and a current loop transmission means connecting said sensor means and central control means, said current loop transmission means delivering the control signals to said sensor means as discrete current levels and receiving the electrical signal from said sensor means as a current level.
-
-
13. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means, the sensor means includes an ultrasonic transducer and a stepped gain amplifier whose gain is controlled by the control signal, the stepped amplifier has (i) a variable gain amplifier connected to said transducer, (ii) a plurality of switched gain stages with at least two states, the gain of said switched gain stages being lower in one state than in the other, said switched gain stages being in series with each other and said variable gain amplifier, and (iii) means for controlling the state of each stage of said switched gain stages in response to particular levels of the control signal; and a current loop transmission means connecting said sensor means and central control means, said current loop transmission means delivering the control signals to said sensor means as discrete current levels and receiving the electrical signal from said sensor means as a current level. - View Dependent Claims (14, 15)
-
-
16. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means, the sensor means includes (i) an ultrasonic transducer, (ii) a stepped gain amplifier whose gain is controlled by the control signal, (iii) a rectifier means for converting the output of the stepped gain amplifier into a d.c. level, and (iv) a log converter means for converting the d.c. level from said rectifier means into a log d.c. level signal whose value is the logarithm of the value of the d.c. level from said rectifier means, the log d.c. level signal being transmitted to said central control means by said current loop transmission means; and a current loop transmission means connecting said sensor means and central control means, said current loop transmission means delivering the control signals to said sensor means as discrete current levels and receiving the electrical signal from said sensor means as a current level.
-
-
17. A remote ultrasonic sensor and control system comprising:
-
at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal; a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means, said central control means including (i) a source of signal reference levels, (ii) means for comparing the electrical signals received from the sensor means to one of the reference levels to determine if the sensor is saturated by an ultrasonic signal which is too large for its gain, (iii) means for incrementally adjusting the control signal to the sensor to reduce the gain at the sensor, whenever it is determined that the sensor is saturated, and (iv) means for analyzing the control signal and the received electrical signal to determine the magnitude of the ultrasonic vibrations detected by said sensor means and for providing a first indication signal whenever the magnitude exceeds a first predetermined value. a current loop transmission means connecting said sensor means and central control means, said current loop transmission means delivering the control signals to said sensor means as discrete current levels and receiving the electrical signal from said sensor means as a current level. - View Dependent Claims (18, 19, 20, 21, 22)
-
Specification