Automatic meter-reading and controlling system
First Claim
1. An automatic meter-reading system for reading a meter at a remote station over a communication link from a central station which comprises:
- A. meter-reading terminal equipment at the remote station comprising;
an encoder for converting the indicative information of the meter into information in the form of ohmic resistance; and
a scanner unit having;
at least three predetermined resistors which have different predetermined resistance values from one another;
a group of switches, each of which is respectively connected in series to an output resistance of the encoder or each of the predetermined resistors, and which are arranged in an predetermined sequence; and
a scanner turning on the switches progressively and selectively;
B. a meter-reading center at the central station comprising;
a stabilized D.C. voltage supply;
an electrical signal measuring apparatus for measuring the electrical signals caused by the current passing through input terminals of a four-terminal network including a communication link and for converting the electrical signals into a computer code which is transmitted to a central processor;
a switch for automatically coupling the electrical signal measurement apparatus to the meter-reading terminal equipment over the communication link and for automatically applyingg stabilized D.C. voltage from the supply to input terminals of the four-terminal network after seizing the communication link under the control of a central processor;
andwherein said central processor is connected to the meter reading terminal equipment through the communication link for controlling the operation of the switch in a meter-reading center, the electrical signal measuring apparatus, and the meter-reading terminal equipment for coupling the encoder to the communication link and for measuring the unknown resistance of the encoder over the communication link;
C. means disposed in the meter-reading center for progressively turning on the switches in the scanner unit by driving the scanner under the control of the central processor; and
D. means disposed in the meter-reading center for indirectly measuring the unknown output resistance of the encoder from at least three values of the predetermined resistors in the scanner unit and electrical signals measured by the electrical signal measuring apparatus while selectively connecting each of the predetermined resistors in the scanner unit or unknown output resistance of the encoder to output terminals of the four-terminal network including the communication link, by calculation based upon a set of the following relations for a passive linear four-terminal network ##EQU8## Where Z1 is the input impedance which is the ratio of the input voltage to the input current in case that the four-terminal network is loaded with an impedance Z2 and A, B,C, and D are generalized network parameters termed four general circuit parameters or cascade parameters and there is the following relation between these parameters
space="preserve" listing-type="equation">AD - BC = 1.
0 Assignments
0 Petitions
Accused Products
Abstract
An automatic meter-reading system monitors broadly distributed utility meters over a communication link by indirectly measuring the resistance value representative of the digit shown on the meter from calculation using the equation derived from the theory of four-terminal network. Based on the similar principle, an automatic remote controlling system monitors the answer-back signal representative of the condition of the controlled equipment at a remote station. Similarly, an automatic meter-reading system monitors a telephone subscriber'"'"'s telephone call meter centrally located in a telephone exchange office.
-
Citations
10 Claims
-
1. An automatic meter-reading system for reading a meter at a remote station over a communication link from a central station which comprises:
-
A. meter-reading terminal equipment at the remote station comprising; an encoder for converting the indicative information of the meter into information in the form of ohmic resistance; and
a scanner unit having;at least three predetermined resistors which have different predetermined resistance values from one another; a group of switches, each of which is respectively connected in series to an output resistance of the encoder or each of the predetermined resistors, and which are arranged in an predetermined sequence; and a scanner turning on the switches progressively and selectively; B. a meter-reading center at the central station comprising;
a stabilized D.C. voltage supply;an electrical signal measuring apparatus for measuring the electrical signals caused by the current passing through input terminals of a four-terminal network including a communication link and for converting the electrical signals into a computer code which is transmitted to a central processor; a switch for automatically coupling the electrical signal measurement apparatus to the meter-reading terminal equipment over the communication link and for automatically applyingg stabilized D.C. voltage from the supply to input terminals of the four-terminal network after seizing the communication link under the control of a central processor; and wherein said central processor is connected to the meter reading terminal equipment through the communication link for controlling the operation of the switch in a meter-reading center, the electrical signal measuring apparatus, and the meter-reading terminal equipment for coupling the encoder to the communication link and for measuring the unknown resistance of the encoder over the communication link; C. means disposed in the meter-reading center for progressively turning on the switches in the scanner unit by driving the scanner under the control of the central processor; and D. means disposed in the meter-reading center for indirectly measuring the unknown output resistance of the encoder from at least three values of the predetermined resistors in the scanner unit and electrical signals measured by the electrical signal measuring apparatus while selectively connecting each of the predetermined resistors in the scanner unit or unknown output resistance of the encoder to output terminals of the four-terminal network including the communication link, by calculation based upon a set of the following relations for a passive linear four-terminal network ##EQU8## Where Z1 is the input impedance which is the ratio of the input voltage to the input current in case that the four-terminal network is loaded with an impedance Z2 and A, B,C, and D are generalized network parameters termed four general circuit parameters or cascade parameters and there is the following relation between these parameters
space="preserve" listing-type="equation">AD - BC = 1.
-
-
2. An automatic meter-reading system for reading a meter at a remote station over a telephone line from a central station, which comprises:
-
A. meter-reading terminal equipment at the remote station comprising; an encoder for converting the indicative information of the meter into information in the form of ohmic resistance;
a scanner unit having;a plurality of predetermined resistors which have different predetermined resistance values from one another; a group of switches, each of which is respectively connected in series to an output resistance of the encoder or each of the predetermined resistors, and which are arranged in a predetermined sequence; and a scanner turning on the switches progressively and selectively; and a coupler unit having; an alert and coupling signal detector for detecting an alert and coupling signal from a meter-reading center; and
a coupling relay responsive to the coupling signal received by the detector for connecting the scanner unit and the encoder to a telephone line;B. a meter-reading center at the central station comprising;
an automatic dialing unit;a stabilized D.C. voltage supply; an electrical signal measuring apparatus for measuring the electrical signals caused by the current passing through the input terminals of a four-terminal network including a communication link and for converting the electrical signals into a computer code which is transmitted to a central processor; a switch for automatically coupling the electrical signal measurement apparatus to the meter-reading terminal equipment over the communication link and for automatically applying stabilized D.C. voltage from the supply to input terminals of the four-terminal network after seizing the communication link under the control of a central processor; and wherein said central processor is connected to the meter-reading terminal equipment through the communication link for controlling the operation of the automatic dialing unit, the switch in a meter-reading center, the electrical signal measuring apparatus, and the meter-reading terminal equipment for coupling the encoder to the communication link and for measuring the unknown resistance of the encoder over the communicating link; C. means disposed in the meter-reading center for progressively turning on the switches in the scanner unit by driving the scanner under the control of the central processor; and D. means disposed in the meter-reading center for indirectly measuring the unknown output resistance of the encoder from at least two values of the predetermined resistors in the scanner unit and electrical signals measured by the electrical signal measuring apparatus while seizing the meter-reading terminal equipment before alerting or selectively connecting each of the predetermined resistors in the scanner unit or unknown output resistance of the encoder to output terminals of the four-terminal network including the communication link, by calculation based upon a set of the following relations for a passive linear four-terminal network ##EQU9## where Z1 is the input impedance which is the ratio of the input voltage to the input current in case that the four-terminal network is loaded with an impedance Z2 including an opencircuited output and A, B, C, and D are generalized network parameters termed four general circuit parameters or cascade parameters and there is the following relation between these parameters
space="preserve" listing-type="equation">AD - BC = 1. - View Dependent Claims (3, 4, 5, 6, 7)
-
-
8. An automatic controlling system for controlling equipment at a remote station over a communication link from a central station which comprises:
-
A. a scanner unit at a remote station having; a plurality of predetermined resistors which have different predetermined resistance values from one another; a group of switches, each of which is respectively connected in series to each of the predetermined resistors and which are arranged in a predetermined sequence; and
a scanner turning on the switches progressively and selectively;B. a controlling center at a central station comprising;
a stabilized D.C. volage supply;an electrical signal measuring apparatus for measuring the electrical signals caused by the current passing through input terminals of a four-terminal network including a communication link and for converting the electrical signals into a computer code which is transmitted to a central processor; a switch for automatically coupling the electrical signal measurement apparatus to the scanner unit at a remote station over the communication link and for automatically applying stabilized D.C. voltage from the supply to input terminals of the four-terminal network after seizing the communication link under the control of a central processor; and wherein said central processor is connected to the controlling terminal equipment through the communication link for controlling the operation of the switch in a controlling center, the electrical signal measuring apparatus, the scanner unit, and the controlled equipment at a remote station for coupling the scanner unit and the controlled equipment at a remote station to the communication link and for checking the predetermined resistance as an answer-back signal over the communication link; C. means for connecting a predetermined resistor corresponding to the controlled condition of the equipment at a remote station in series to the switch turned on at the predetermined scanned position of the scanner by a contact associating with the operation of the equipment, when the equipment has been controlled from the controlling center; D. means disposed in the controlling center for progressively turning on the switches in the scanner unit by driving the scanner under the control of the central processor; and E.means disposed in the controlling center for indirectly measuring the resistance of the predetermined resistor corresponding to the controlled condition of the equipment at a remote station from values of the predetermined resistors in the scanner unit and electrical signals measured by the electrical signal measuring apparatus while selectively connecting each of the predetermined resistors in the scanner unit or the predetermined resistor corresponding to the controlled condition of the equipment to output terminals of the four-terminal network including the communication link, by calculation based upon a set of the following relations for a passive linear four-terminal network ##EQU10## where Z1 is the input impedance which is the ratio of the input voltage to the input current in case that the four-terminal network is loaded with an impedance Z2 and A, B, C, and D are generalized network parameters termed four general circuit parameters or cascade parameters and there is the following relation between these parameters
space="preserve" listing-type="equation">AD - BC = 1.
-
-
9. An automatic meter-reading system for reading a subscriber'"'"'s meter centrally equipped in an automatic telephone exchange office, which comprises:
-
A. an encoder for converting the indicative information of a subscriber'"'"'s meter into information in the form of ohmic resistance;
a stabilized D.C. voltage supply;an electrical signal measuring apparatus for measuring the electrical signals caused by the current passing through input terminals of a four-terminal network including one wire of the communication link selected by the automatic telephone switching system and a line connecting the meter-reading connection exchange office unit and the meter-reading center and for converting the electrical signals into a computer code which is transmitted to a central processor; a switch for automatically coupling the electrical signal measuring apparatus to the meter-reading connection exchange office unit through the communication link and for automatically applying stabilized D.C. voltage from the supply to input terminals of the four-terminal network after seizing the communication link under the control of a central processor; and wherein said central processor is connected to the meter-reading terminal equipment through the communication link for controlling the operation of the automatic dialing unit, the switch in a meter-reading center, the electrical signal measuring apparatus, and the scanner unit in the meter-reading connection exchange office unit for coupling the encoder to the communication link and for measuring the unknown resistance of the encoder over the communication link; B. a meter-reading connection exchange office unit comprising; an encoder connecting unit having a group of diodes for connecting together the encoder and the predetermined resistors in series with each of the diodes respectively to one wire of each subscriber line, the diodes preventing the causation of a cross-contact fault between the subscriber lines and preventing the formation of turnaround circuits to the encoder through another subscriber'"'"'s encoder connecting unit; a scanner unit for common use by a plurality of subscribers, having; a plurality of predetermined resistors which have different predetermined resistance values from one another; a group of switches arranged in a predetermined sequence, each of which is multiconnected to a plurality of subscriber'"'"'s communication links in series with the diode in the encoder connecting unit and an output resistance of the encoder or each of the predetermined resistors; and a scanner turning on the switches progressively and selectively; C. a meter-reading center at the telephone exchange office or the central station comprising; an automatic dialing unit; D. means disposed in the meter-reading center for progressively turning on the switches in the scanner unit by driving the scanner through one wire of a communication link of an automatic telephone switching system and line connecting the meter-reading connection exchange office unit and the meter-reading center under the control of the central processor; and E. means disposed in the meter-reading center for indirectly measuring the unknown output resistance of the encoder from values of the predetermined resistors in the scanner unit an electrical signals measured by the electrical signal measuring apparatus while selectively connecting each of the predetermined resistors in the scanner unit or unknown output resistance of the encoder to one wire of the communication link selected by the telephone switching system, by calculation based upon a set of the following relations for a passive linear four-terminal network ##EQU11## where Z1 is the input impedance which is the ratio of the of the input voltage to the input current in case that the four-terminal network is loaded with an impedance Z2 and A, B, C, and D are generalized network parameters termed four general circuit parameters or cascade parameters and there is the following relation between these parameters
space="preserve" listing-type="equation">AD - BC = 1. - View Dependent Claims (10)
-
Specification