Abstract:
A apparatus for providing onsite programming of an automatic meter reader apparatus via an infrared transceiver mounted within the housing of the apparatus and communicating with an internal processor. A portable infrared transceiver and processor establishes data communication with the processor in the automatic meter reader housing in Internet TCP/IP data communication protocol. A disconnect switch mounted in the housing is responsive to signals communicated through the infrared transceiver or from the central site for controlling the connection and disconnection of electric power to the use site.

Description:
CROSS REFERENCE TO CO-PENDING APPLICATION  
       [0001]    This application claims the benefit of the filing date of co-pending provisional U.S. Patent Application Serial No. 60/235,122, filed Sep. 25, 2000 and entitled “POINT OF USE DIGITAL ELECTRIC ENERGY MEASUREMENT, CONTROL AND MONITORING APPARATUS”. 
     
    
     
       BACKGROUND  
         [0002]    The present invention relates, in general, to apparatus for measuring and controlling the supply of electric energy at a use site.  
           [0003]    In the electric utility industry, watthour meters are typically employed to measure electric power used at a building or home site. A socket housing is mounted on a convenient wall of the residence or commercial building and contains pairs of line and load terminals which are respectively connected to the electric utility line conductors and the building load distribution conductors. The terminals typically receive blade contacts on a plug-in watthour meter to complete an electric circuit through the meter between the line and load terminals.  
           [0004]    Plug-in socket adapters and socket adapters/extenders, both hereafter referred to simply as socket adapters, are designed to plug into the meter socket housing terminals. Such socket adapters are employed to convert a ringless style socket to a ring style socket or to extend the mounting position of the jaw terminals in the socket outward from the socket for mounting various electrical equipment, such as test devices or survey recorders, in the socket. The watthour meter is then plugged into jaw contacts carried within the socket adapter. The socket adapter jaw contacts are connected, either integrally or via separate electrical connections, to blade terminals extending rearwardly of the socket adapter housing for plug-in engagement with the socket terminals or jaw contacts.  
           [0005]    Meter reading personnel periodically inspect each meter site and record utility meter readings, either visually or by using a probe to retrieve power usage data stored in solid state memory of the watthour meter.  
           [0006]    To increase data collection efficiency and reliability, watthour meters are now available which include interface equipment designed to permit remote interrogation of the meter and transmission of electric power usage data. Utility meters located at each customer site are connected in data communication to a central billing facility via various communication methods, including power line signal transmission, dedicated signaling lines, use of the public telephone switching network, and radio frequency signal transmission.  
           [0007]    While prior automatic meter readers have been provided with programmability so as to be able to be programmed, uploaded or downloaded with data from the central utility site via the established bidirectional communication network connecting the central site to the each meter reader apparatus, it is frequently necessary for a utility service person, when servicing a meter at the use site, such as during the initial installation, repair, testing, etc., to have the ability to access and communicate with the processor of the automatic meter reader for uploading and downloading data, reprogramming certain programmable features of the automatic meter reader, initiating a data transfer to or from the central site, etc.  
           [0008]    While optical communication ports have been provided on electronic watthour meters, such has been provided only with the capability of establishing a data communication link between a handheld programmer and the meter and not to any remote site via a communication link coupled to the meter.  
           [0009]    Thus, it would be desirable to provide an electrical energy measurement apparatus having improved communication features which allow on-site data communication with the energy measurement apparatus or automatic meter reader apparatus from a portable processor based device and through the measurement apparatus to a remote central reporting site.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention is an electrical energy measurement apparatus having a unique optical communication port and communication protocol which provides on-site data communication with a portable communication device disposed at the meter reader location for controlling parameters of the electrical energy measurement or automatic meter reader apparatus as well as for establishing data communication with the automatic meter reader apparatus in the communication format used by the automatic meter reader and the remote central site.  
           [0011]    In one aspect, the apparatus includes a processor and memory coupled in data communication, both mounted within a housing. The housing has a communication window which provides a field of view for an optical transceiver mounted in the housing and signal coupled to the processor. Preferably, the optical transceiver utilizes infrared signals to establish a two-way data communication link with a portable infrared transceiver on the portable communication device.  
           [0012]    The internal processor establishes data communication through the optical transceiver with the nearby portable processor using the same Internet data communication protocol employed for data communication between the automatic meter reader apparatus and the remote central or reporting site.  
           [0013]    This data communication protocol also enables the portable processor to establish data communication with the remote central site both to initiate a data transfer between the automatic meter reader apparatus and the central site or to receive programming or other data from the central site. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0014]    The various features, advantages and other uses of the present invention are more apparent by referring to the following detailed description and drawing in which:  
         [0015]    [0015]FIG. 1 is a schematic diagram of an electric energy management apparatus according to the present invention;  
         [0016]    [0016]FIG. 2 is an exploded, perspective view showing the electric energy management apparatus according to the present invention mountable in a watthour meter socket;  
         [0017]    [0017]FIG. 3 is a perspective view of the electric energy management apparatus without the internal circuit board, the disconnect switch and the shell;  
         [0018]    [0018]FIG. 4 is a perspective view of the electric energy management apparatus shown in FIG. 3 including the optional disconnect switch;  
         [0019]    [0019]FIG. 5 is a side elevational view of the housing of the electric energy management apparatus with a portion of the sidewall of the housing removed to show the internal components of the electric energy management apparatus of the present invention;  
         [0020]    [0020]FIG. 6 is a front elevational view of the circuit board of the electric energy management apparatus shown in FIG. 5;  
         [0021]    [0021]FIG. 7 is a block diagram of the major components of the electric energy management apparatus at one customer use site;  
         [0022]    [0022]FIGS. 8A, 8B,  8 C, and  8 D are detailed schematic diagrams of the circuitry of the electric energy management apparatus mounted on the circuit board shown in FIGS. 5 and 6;  
         [0023]    [0023]FIGS. 9A and 9B are flow diagrams of the electric energy management apparatus control program;  
         [0024]    [0024]FIG. 10 is a flow diagram of the power demand windows control sequence of the present electric energy management apparatus;  
         [0025]    [0025]FIG. 11 is a schematic diagram of the disconnect switch control circuitry used with the optional disconnect switch shown in FIG. 4;  
         [0026]    [0026]FIG. 12 is a graph depicting out-of-specification voltages;  
         [0027]    [0027]FIG. 13 is a flow diagram of the “out-of-spec” energy detection sequence;  
         [0028]    [0028]FIG. 14 is a flow diagram depicting the tamper detection sequence;  
         [0029]    [0029]FIG. 15 is a side elevational view of the electric energy management apparatus depicting a partially removed position of the housing from the meter socket;  
         [0030]    [0030]FIG. 16 is a side elevational view, similar to FIG. 15, but showing the housing blade terminals in a fully separated position with respect to the socket jaw contacts;  
         [0031]    [0031]FIG. 17 is a side elevational view of a meter installation depicting the electric energy measurement apparatus of the present invention mounted in a ringless style meter socket;  
         [0032]    [0032]FIG. 18 is a flow diagram of the telephone interrupt and non-interrupt control sequence; and  
         [0033]    [0033]FIG. 19 is a diagram of the optical communication circuit. 
     
    
     DETAILED DESCRIPTION  
       [0034]    Referring now to the drawing, there is depicted a point of use, digital, electrical energy measurement, control and monitoring apparatus for use at individual utility customer sites which has connectivity through a global telecommunication network to a centralized computer control system.  
       Central Utility  
       [0035]    As shown in FIG. 1, a central utility company site is depicted generally by reference number  10 . The central utility site  10  may be the central business office of the utility, a generating station, etc., where utility billing information is accumulated, tabulated and recorded. A central processing unit  12  is located at the central site  10 . The central processing unit  12  may be any suitable computer, such as a mainframe, a PC, a PC network, workstation, etc., having the capacity of handling all of the utility company customer billing transactions and/or the remote data communications described hereafter. The central processing unit  12  communicates with a memory  14  which stores, identification data specific to each utility customer, as well as other data regarding the power usage of each customer. The memory  14  may include both hard disc storage memory and on-board memory. Although high voltage, electrical power distribution lines denoted generally by reference number  16  for a three-wire, single-phase electrical system, are shown as extending between the central utility site  10  to each utility customer  18 ,  19 , etc., it will be understood that the electrical power distribution lines  16  may extend from a separate electrical power generating site with appropriate voltage transformations to each customer site, and not directly from the central utility site  10 . Further, it will be understood that the electrical power distribution lines  16  may provide three-phase power to any customer site.  
         [0036]    As shown in FIG. 1, various input and output devices, such a keyboard, printer(s)  13 , display terminals or monitors  15 , etc., may also be connected to the central processing unit  12  as is conventional. In addition, one or more modems  20  are connected to the central processing unit  12  at the central utility site  10  and to a conventional telephone wiring network denoted generally by reference number  22 . The telephone wiring network  22  may be conventional telephone wires, as well as fiber optics, satellite, microwave, cellular telephone communication systems and/or combinations thereof. The modem  20 , which may be any conventional modem, functions in a known manner to communicate data between a processor and the telephone network.  
         [0037]    Also stored in the memory  14  are the various software control programs used by the central processing unit  12  to automatically communicate with the electrical energy management apparatus at each utility customer  18 ,  19  as described hereafter. The memory  14  also stores the power usage data for each utility customer  18 ,  19  as well as various billing routines utilized by a particular utility company.  
         [0038]    Generally, the software control program stored in the memory  14  is a menu driven database capable of handling multiple simultaneous calls to a number of remote apparatus at the customer sites  18 ,  19 . The control program stores each customer&#39;s power usage in accumulated KWH and KVA, for example, and instantaneous voltage, current and power factor measurements. Also, the control program generates periodic summary printouts via the printer  13 .  
         [0039]    The control program enables the utility to remotely program each energy management apparatus from the central site  10 . Such programmable features include time, date and year data, a multi-level security code for communication access, receive call and originate call modes, line voltage quality set points, start and end times for multiple demand billing period intervals, i.e., three intervals in each 24 hour period, the date, time and duration of a communication window for communication with the central site  10 , etc.  
         [0040]    Various main system menu screens may be generated by the CPU  12  to enable communication with any of the remote units. Further details concerning the generation and use of such menu screens can be had by referring to U.S. Pat. No. 5,590,179, the entire contents of which are incorporated herein by reference.  
         [0041]    According to a unique feature of the present automatic meter reader apparatus, CPU  12  communicates with a global telecommunications network that is separate from the conventional telephone line network  22  through an interface including a modem connection  20  to an Internet service provider (ISP)  20  which communicates with a worldwide telecommunications network, such as the Internet or world wide web. The CPU  12  can generate an appropriate identification number (I.D.) or address for any of the remote units. This I.D. can be transmitted by the ISP  20  through the Internet  21  to any of the individual use sites  18 ,  19 , etc.  
       Remote Utility Customer  
       [0042]    As shown in FIGS. 1 and 2, a plurality, such as tens or even hundreds or thousands of utility customer sites  18 ,  19 , are connected to the electrical power distribution network  16  at remote locations of varying distances from the central utility company site  10 .  
         [0043]    As is conventional, each utility customer site  18 , as shown in FIG. 1, includes a conventional utility meter socket  30  having a plurality of internally mounted jaw contacts or terminals  32  which are connected to the single-phase three-wire line conductors of the electrical distribution network  16 . Although not shown in FIG. 1, the separate jaw terminals  32  in the socket  30  are connected to the individual service or load conductors at each utility customer site  18 . In a conventional application, the socket  30  is mounted at a suitable location at the utility customer site  18 , such as on an exterior wall, with the load conductors extending from the socket  30  to the building wiring circuits.  
       Remote Unit  
       [0044]    A digital, electric energy management apparatus (hereafter “remote unit”)  34  is provided for recording, measuring, controlling and monitoring electrical power usage at a particular customer site  18 . The remote unit  34  has a plurality of outwardly extending, blade-type, electrical terminals  36  which electrically engage the jaw contacts or terminals  32  in the socket  30 .  
         [0045]    As shown in FIGS. 1 and 2, and in greater detail in FIGS. 3, 4 and  5 , the remote unit  34  of the present invention, in a preferred embodiment, includes a base denoted generally by reference number  40 . The base  40  is snap-in connectable in the meter socket  30 . However, according to the present invention, the base  40  includes internally mounted electrical energy measurement and telecommunication circuits as described in greater detail hereafter. The use of the base  40  to house the automatic meter reading circuitry is a preferred embodiment of the present invention. It will be understood, however, that such electrical energy measurement and control circuitry, as described hereafter, can also be mounted at each customer site  18 ,  19  by other means, such as in an enclosure separate from a standard watthour meter and the meter socket.  
         [0046]    In general, the remote unit  34  includes a two-part housing formed of the base  40  having a base wall  42  and a shell  44  which are releasably joined together by a snap-in and rotate connection. As described hereafter, a plurality of electrical terminals  34  are mounted in the base  40 . The electrical terminals  47  are provided in the base  40  in any number, type and arrangement depending upon the electrical power service for a particular application. By way of example only, the electrical terminals  47  are arranged in the base  40  in a first pair of line terminals  54  and  56  and a second pair of load terminals  58  and  60 .  
         [0047]    A peripheral flange  48  is formed on the base  40  which mates with a similarly formed flange  33  on the watthour meter socket or housing  30  for mounting the remote unit  34  to the watthour meter socket  30 . A conventional seal or clamp ring  62 , such as a seal ring disclosed in U.S. Pat. No. 4,934,747, the contents of which are incorporated herein by reference, is mountable around the mating flanges  48  and  33  to lockingly attach the remote unit  34  to the socket  30  and to prevent unauthorized removal of or tampering with the remote unit  34 .  
         [0048]    It will also be understood that the remote unit  34  and the socket  30  may be configured for a ringless connection. In this type of connection, not shown, the cover of the socket  30  is provided with an aperture which is disposable over the remote unit  34 . The cover is locked to the socket  30  enclosure after the remote unit  34  has been inserted in the socket  30  and through the aperture in the cover.  
         [0049]    The base  40  and the base wall  42  has generally circular configuration centered within an integrally formed annular side wall  44  which terminates in an outer edge  46 . The flange  48  projects radially outward from the sidewall  44  at the general location of the base wall  42 . A plurality of circumferentially spaced notches  50  are formed in the flange  48  for reasons which will be described in greater detail herein.  
         [0050]    At least one and preferably two ground tabs  51 , only one of which is shown in FIG. 3, are mounted on the exterior surface of the base wall  42  and have an radially outer end which is positioned within one of the notches  51  as shown in FIG. 3. The ground tabs  51  are adapted to engage a ground connection in the meter socket  30 , as is conventional and as is described in greater detail hereafter.  
         [0051]    The shell  44  has a generally cylindrical configuration formed of a sidewall  45  and an end wall  53 . An annular flange  47  projects radially from one end of the sidewall  45  as shown in FIGS. 2 and 5. The flange  47  has a stepped shape formed of a radially extending leg and an axially extending leg. The flange  47  overlays the flange  48  on the base  40  and receives the sealing ring  37  thereover as described above.  
         [0052]    A plurality of arcuate slots  49 , such as three slots  49  by way of example only, are formed in the radially extending leg of the flange  47 . A generally L-shaped lock arm  51  projected interiorly from the radially extending leg of the flange  47  along one inside edge of each slot  49 , as shown in FIG. 5. The L-shaped lock arm  51  is alignable with one of the notches  51  in the base  40  when the shell  44  is joined to the base  40 . Rotation of the shell  44  relative to the base  40  causes the lock arm  51  to slide underneath the bottom edge of the flange  48  on the base  40  to lock the shell  44  to the base  40 .  
         [0053]    It will be understood that alignable apertures may be formed in the flange  47  of the shell  44  and the flange  48  of the base  40  in the rotated, locked position for receiving a seal member, such as a conventional watthour meter seal ring, not shown, to lockingly attach the shell  44  to the base  40  and to provide an indication of tampering with the remote unit  34  after the remote unit  34  has been mounted on the socket  30 .  
         [0054]    As also shown in FIGS. 1 and 2, and in greater detail in FIG. 5, the end wall  53  of the shell  44  is provided with an aperture  55  which has an under notch or undercut formed about the periphery of the aperture  55  as shown in FIG. 5. The aperture  55  is adapted for receiving a transparent cover  57 , formed, by example, of Lexan, and having a notched peripheral edge which fits within the undercut formed about the periphery of the aperture  55 . A plurality of posts  59  project inwardly from the undercut surrounding the aperture  55  in the end wall  53  of the shell  44  and are adapted to engage apertures formed about the periphery of the cover  57  to align and mount the cover  57  to the end wall  53 . Fasteners, such as lock nuts, not shown are mountable over the posts  59  to lock the cover  57  in the end wall  53 .  
         [0055]    Although not shown in FIG. 5, portions of the transparent cover  57  are masked or blacked out to provide separate windows, one for the display  222  and one for the opto-communication port  134 .  
         [0056]    A plurality of apertures  52  are formed in the base wall  42  at the normal jaw contact positions of a watthour meter. For the single phase remote unit  34  described herein by way of example only, four apertures  52  are formed in the base wall  42  and respectively received the line blade terminals  54  and  56  and the load blade terminals  58  and  60 . The blade terminals  54 ,  56 ,  58  and  60  have one end portion disposed interiorly within the base  40  extending away from one side of the base wall  42  and an external portion, shown in FIG. 5, which projects exteriorly of the opposed surface of the base wall  42  and adapted to slidably engage the jaw contacts  32  in the watthour meter socket  30 .  
         [0057]    Although not shown, one of the apertures formed in the exterior portion of each blade terminal  54 ,  56 ,  58  and  60  can receive a lock member, such as a cotter pin, conventionally used in watthour meters, to fixedly secure each blade terminal  54 ,  56 ,  58  and  60  to the base wall  44 .  
         [0058]    A plurality of bosses  62 , such as three bosses by way of example only, are formed on the base wall  42  and project therefrom to co-planar upper ends as shown in FIG. 5. Each boss  62  can be solid or hollow, but has an upper end bore  64  adapted to receive a fastener, such as a screw, for securing a circuit board  66  containing the remote unit  34  circuitry thereon. Thus, the bosses  62  form a support for the circuit board  66  as shown in FIG. 5. This spaces the circuit board  66  above the blade terminals  54 ,  56 ,  58  and  60  as well as above an optional disconnect switch  70 .  
       Disconnect Switch  
       [0059]    The provision of a disconnect switch  70  is optional in the remote unit  34  of the present invention. However, the disconnect switch  70  provides valuable features when used in the tampering detect sequence described hereafter. The disconnect switch  70  may also be remotely controlled by the central utility site  10  to control the power at a particular customer site.  
         [0060]    The disconnect switch  70  can be of conventional construction in that it includes two switchable contacts, which are adapted to be respectively connected between one line and one load blade terminal, such as blade terminals  54  and  58  and  56  and  60 .  
         [0061]    To this end, the disconnect switch  70  is provided with a pair of line terminals  72  and  74  which project outwardly from one side of the housing of the disconnect switch  70  and a pair of load terminals  76  and  78  which project from an opposite edge or surface on the disconnect switch  70 . The terminals  72  and  74  are adapted to be disposed in registry with the load blade terminals  54  and  56  extending through the base wall  42 . Suitable fasteners, such as rivets, are employed to securely and electrically connect the terminals  72  and  74  to the load blade terminals  54  and  56 , respectively. Likewise, the load terminals  74  and  78  are disposed in proximity with the load blade terminals  58  and  60  and are secured thereto by means of suitable fasteners as described above. In this manner, the disconnect switch  70  can be easily mounted in the base  42  without interfering with the circuit board  66 .  
         [0062]    Although the disconnect switch blade terminals  72 ,  74 ,  76  and  78  have been described as being separate from the blade terminals  54 ,  56 ,  58  and  60  in the base  40 , it will be understood that the disconnect terminals  72 ,  74 ,  76  and  78  can be integrally formed as a one piece, unitary structure with the blade terminals  54 ,  56 ,  58  and  60  to form a generally L-shaped blade terminal projecting from the disconnect switch  70  which has an end portion, similar to the blade terminals  54 ,  56 ,  58  and  60 , which is slidingly engagable through one of the apertures in the base wall  42 .  
         [0063]    [0063]FIG. 11 depicts the control circuitry for the disconnect switch  70  which is mounted on a circuit board attached to the bottom surface of the circuit board  66  facing the disconnect switch  70 . The disconnect switch control circuitry includes a pair of flip-flops which remember the state of an internal relay in the disconnect switch  70 . The flip-flops enable the disconnect switch  70  contacts to be switched to the last state after power is reapplied to the remote unit  34  after a power interruption, removal of the remote unit  34  from the meter socket  30 , etc.  
         [0064]    The disconnect switch  70  may be controlled by a signal from the central site  10  to either “on” or “off” states as dictated by the electric utility. The signal will be received by the circuit and cause the flip-flops to switch states in accordance with the on or off signal. At the same time, a push button  71 , shown in FIG. 11, is mounted at a convenient location on the shell  44  and the base  42  to enable a customer, after receiving appropriate instructions from the electric utility, to manually reset the disconnect switch  70  to the “on” state.  
       Remote Unit Circuitry  
       [0065]    A general block diagram and the circuitry of the major components of the remote unit  34  which are mounted in the base  40  at each utility customer site  18  is shown in FIGS.  7 ,  8 A- 8 D and  19 . The circuit includes a power supply  122 , voltage and current sensing circuit, an analog to digital conversion circuit  124 , a central processing unit and associated logic  126 , memories  128  and  129 , a telephone communication modem  130 , an opto-communication port  254 , and a clock. The details of these major components will now be described.  
         [0066]    As is conventional, the electrical power distribution network  16  from the central utility company generating site typically carries 240 VAC. A single-phase, three-wire power distribution network  16  is shown in FIGS. 1 and 2 with three wires connected to the electrical power distribution network  16  at each utility customer site  18 . Each line  134  and  136  carries 120 VAC RMS with respect to neutral or ground wire.  
         [0067]    The power supply  122 , shown in FIG. 8C, provides regulated, low level DC power at the preferred ±DC levels required by the electronic components used in the circuit  120 .  
         [0068]    The circuit  120  also includes a voltage sensing network denoted in general by reference number  180  in FIG. 8A. The voltage sensing network receives 120 VAC RMS 60 Hz input from the utility lines. One set of voltage inputs including voltage lead line connections  182  and  183  are between one lead line and neutral; while the other pair of inputs  184  and  183  is between the other lead line conductor and neutral. The voltage lead  182  is input to a combination of series connected, differential amplifiers  185 ,  186  which have a settable gain of 1/100, for example. The output of the differential amplifiers is input to an A/D converter  124 . The other line connection  184  is input to a similar combination of differential amplifiers thereby resulting in two separate voltage inputs as shown by reference numbers  190  and  191  in FIG. 8A which are connected to other inputs of the A/D converter  124 . The differential amplifiers  186  provide an instantaneous voltage corresponding to the lead line voltage present on the conductors  182 ,  183  and  184  which is within the input range of the A/D converter  124 . It should be understood that the input voltages supplied to the A/D converter  124  are instantaneous voltages.  
         [0069]    The current sensing network of the circuit  120  includes first and second current transformers  200  and  202 , respectively, as shown in FIGS.  3 - 5 . The current transformers  200  and  202  each include a high permeability toroid which is disposed around a circular wall  199  surrounding each of the line blade terminals  54  and  56 , respectively, in the base  40 . The circular wall  199  is preferably a continuous or discontinuous annular member or members which are fixedly disposed on the base  40 . Preferably, the wall  199  is integrally formed with and extends from the plane of the base  40 .  
         [0070]    The walls  199  provide a center support for the toroidal current transformers  200  and  202  to fixedly mount the current transformers  200  and  202  on the base  40 . This fixes the position of the current transformers  200  and  202  with respect to the inner disposed blade terminals  54  and  56 , respectively. Once the meter is calibrated, the magnetic flux between of the current transformers  200  and  202  and the current flowing through the blade terminals  54  and  56  remains fixed thereby increasing the accuracy of the electric power measurement of the meter as compared to prior art automatic meter reader devices in which the current transformers are not held in a fixed position and are capable of movement with respect to the blade terminals.  
         [0071]    The current transformers  200  and  202  are precision, temperature stable transformers which provide a ±10 volt output voltage signal in proportion to the instantaneous current flowing through the line conductor. The electrical conductive coil of each current transformer  200  and  202  maybe covered by a protective insulating coating, with the conductive coil leads or outputs extending therefrom.  
         [0072]    The outputs  201  from the current transformer  200  are input through a conditioning circuit to an amplifier  206 . The output of the differential amplifier  206 , which represents the scaled instantaneous current in the line conductor  134 , is supplied as an input to the A/D converter  124  as shown in FIG. 8A.  
         [0073]    A similar signal conditioning circuit is provided for the current transformer  202 . The output leads  203  from the current transformer  202  are supplied to a differential amplifier  211 . The output of the differential amplifier  211  is also supplied as a separate input to the A/D converter  124 .  
         [0074]    The A/D converter  124  includes internal sample and hold circuits to store continuous voltage and current signal representations before transmitting such instantaneous voltage and current representations to other portions of the circuit  120 , as described hereafter.  
         [0075]    The twelve bit output from the A/D converter  124  is connected to an electronic programmable logic device (EPLD)  127 , shown in FIG. 8A, which stores the instantaneous line voltages and currents and performs at least an initial kilowatt hour (KwH) calculation at the sample rate of the A/D converter  124  on each link. This gives a real time, dual channel power measurement since the power on each separate 120 VAC line and on the 240 VAC line is separately calculated. This avoids the averaging employed in prior power metering devices and provides greater power measurement accuracy.  
         [0076]    The individual line voltages and currents as well as the calculated KwH are accumulated for a predetermined time period, before the data is transmitted through a high speed data bus to a central processing unit  126 . The central processing unit  126 , in a preferred embodiment which will be described hereafter by way of example only, is a 16 bit microcontroller, Model No. ANI86ES, sold by Analog Devices. The microcontroller  126  executes a control program stored in the flash memory  128 , or backup EEPROM memory  129 , as described hereafter, to control the operation of the circuit  120 . Clock signals from a real time clock circuit  127 , in FIG. 8B, are supplied to the processing unit  126  and other circuit elements.  
         [0077]    The microcontroller  126  also drives a display means  222 , such as a liquid crystal display, for consecutively displaying for a brief time interval, for example, the total kilowatt hours (KwH) total KVA total and KVA reactive, date, time, individual line current and voltage, and average power factor. The display  222  can be mounted, for example, at a suitable location on the circuit board  66 , for easy visibility through the transparent cover  57  mounted in the end wall of the shelf  44 . The display  222 , in a preferred embodiment, contains  16  characters divided into significant digits and decimal digits.  
         [0078]    Referring now to FIGS. 9A and 9B, there is depicted a flow diagram of the sequence of operation of the control program executed by the CPU  126 . After initialization, the CPU  126  executes a number of steps to initialize various registers and to set up to receive voltage and current data. Maintenance routines are also executed to determine if any of the components, such as the communication channels, the display  226 , etc., need service. If any maintenance or time event, such as a zero crossing of the voltage or current waveforms is detected, the CPU  126  executes the detected event step in a priority order from high to low as shown in FIG. 9B which depicts an exemplary priority order of event processing.  
       Tamper Detection  
       [0079]    The remote unit  34  of the present invention is provided with a unique tamper detection circuit which not only detects at least one or more different types of tamper events; but is capable of recording the time of day and the total duration of the tamper event as well as optionally taking action such as switching the disconnect switch  70  to an open condition thereby preventing any further application of electric power through the disconnect switch  70  to the customer site  18 ,  19  when the remote unit  34  is reinserted into the socket  30 .  
         [0080]    The base  40  of the remote unit  34  is provided with at least one and, preferably, two ground tabs  51 , one being shown in FIG. 3, which extend radially along the back surface of the base wall  42  into one of the notches  50  on the flange  48  surrounding the base wall  42 . Each ground tab  51  is positioned to engage a ground connection in the socket  30  to complete a ground circuit from the remote unit  34  through the socket  30  to earth ground.  
         [0081]    The tamper detection sequence of the present invention is based on the mounting relationship of the blade terminals  54 ,  56 ,  58  and  60  in the jaw contacts  32  in the socket  30  and the connection between the ground tabs  51  and the mating ground tabs in the socket  30 . In addition, the voltage and currents of each of the two legs or phases of power supply to a customer use site  18  as well as the voltage and current of the center ground or neutral connection are continuously monitored as part of the tamper detection.  
         [0082]    Since the blade terminals  54 ,  56 ,  58  and  60  extend a distance, such as approximately ½ inch, into the jaw contacts  32  in the socket  30  when in the full mounted position shown in FIG. 5, any attempt to remove the remote unit  34  from the socket  30  will initially cause the ground tab  51  to separate from the mating ground tab in the socket  30  in a timed sequence before the blade terminals  54 ,  56 ,  58  and  60  completely separate from the respective jaw contacts  32  and shown in FIGS. 15 and 16.  
         [0083]    In a normal operating state when the remote unit  34  is securely mounted in the socket  30 , the voltage on the first and second legs will equal approximately 120 VAC, and the voltage and current on the ground leg will be zero. The current in the first and second legs will be greater than zero.  
         [0084]    During a tamper event when the remote unit  34  is initially pulled from the socket  30 , as shown in FIG. 15, the ground tab  51  will separate from the mating ground connection member in the socket  30 . At this time, the ground current will equal zero while the voltage of the ground line will be greater than zero due to the loss of ground connection. However, the blade terminals  54 ,  56 ,  58  and  60  are still connected to the socket jaw contacts  32  such that current continues to flow through the first and second legs, i.e., i L1  and i L2 &gt;0. Continued separation of the remote unit  34  from the socket jaws  32  will eventually completely separate the blade terminals  54 ,  56 ,  68  and  60  from the socket jaw contacts  32 , as shown in FIG. 16, such that the current flowing through the first and second legs will drop to zero.  
         [0085]    This defines the tamper signature detected by the remote unit  34  of the present invention. Specifically, the tamper signature is the detection of a time delay between the time that the ground current equals zero and a ground voltage is greater than zero and a subsequent time occurrence of at least one of the first and second line and load currents equaling zero. In the case of a power outage, the ground voltage will not be greater than zero, so as to not constitute the tamper signature.  
         [0086]    This sequence is depicted in FIG. 14. The microprocessor, after detecting a tamper signature in step  127  will generate and send a signal, labeled “tamper” in FIG. 8B, to the disconnect switch  70  which will cause the disconnect switch  70  to switch or remain in an open position the next time electric power is supplied to the disconnect switch  70  through the blade terminals. This signal is shown by reference number  129 . The CPU  126  also generates a notification signal  131  which can be transmitted back to the central site  10  to indicated to the utility that a tamper event has occurred. If the utility company chooses to contact the customer at the customer site at which a tamper event was detected, the utility company can notify the customer that tampering has been detected and provide the customer with the time of the start of the tamper detection as well as the total duration of the tamper event. Corrective action can now be easily taken by the utility to address the tamper event.  
         [0087]    Upon reconnecting power to the offending customer site, the central site  10  can send a signal through the communication network described hereafter, to the customer site to set up the disconnect switch circuitry to reapply power to the disconnect switch  70  after the customer pushes pushbutton  71  on the remote unit  34 . This will cause the disconnect switch  70  contacts to switch to the closed state thereby reconnecting a circuit between the line and load blade terminals in the remote unit  34 .  
         [0088]    The signal  131  also contains data relating to the time and date of the start of the detected tamper signature event as well as the time duration of the tamper event. The time and date of the start of the tamper event as well as the duration of the each detected tamper event can be stored in the memory of the remote unit  34  for later transmission to the central site  10  for tamper event recordation, analysis, etc.  
         [0089]    Instead of a control program consisting of software instructions executed by a microprocessor, the above described tamper event detection method can also be implemented in a dedicated electronic circuit formed of electric current and voltage sensors and logic elements which can sense the line and ground circuit voltages and currents as well as a time separation between certain voltages and currents as described above. The outputs of such a circuit can be the“tamper” signal which can be transmitted by various means, such as power line communication, Rf communication, etc., to a central site  10 . The “tamper” signal can be applied directly to the disconnect switch  70  to automatically disconnect the supply of electric power to the meter site at which a tamper event has been detected.  
         [0090]    In FIG. 18, the remote unit  34  of the present invention is shown mounted in a ringless style watthour meter socket  400  which includes a housing  402  and a cover  404 . A raised annulus  406  is formed in the cover  404  surrounding an aperture  408  through which the sidewall of the remote unit  34  extends.  
         [0091]    Inner disposed mounting brackets  410  and  412 , which are fixedly mounted on the sidewalls of the socket housing  402 , extend inward to an inner flange end  414 . The inner flange end  414  is positioned to engage one of the ground tabs  51  extending radially outward on opposite diametric sides of the housing of the remote unit  34 . This completes a ground circuit through the internal circuitry of the remote unit  34  and the earth ground connection in the meter socket  400 .  
         [0092]    The tamper event signature detection method and apparatus according to the present invention takes place in the same manner as that described above.  
       Remote Communications  
       [0093]    A first communication feature of the remote unit  34  of the present invention is uninterruptible telephone service to the customer site  18 . The remote unit  34  intercepts calls by TCP/IP modem interface circuitry that permits the remote unit  34  to answer incoming calls from the central site  40  without detection by the customer, and, additionally, a courtesy transfer feature that automatically disconnects the remote unit  34  from the telephone line and prepares the remote unit  34  for a later retry when the customer picks up the handset on the telephone during a communication between the remote unit  34  and the central site  10   
         [0094]    The uninterruptible telephone service is achieved by connecting the TCP/IP modem interface circuit in series in the telephone(s) of the use site  18 . In this manner, the remote unit  34  can recognize and intercept the ring circuit to receive or transmit data to the central site  10 .  
         [0095]    Initially, the CPU  126  detects a voltage rise before a voltage peak is reached in the ring circuit. The CPU  126  is programmed to recognize the TCP/IP data format from the central site  10 . Upon detecting the TCP/IP format, the CPU  126  routes the incoming telephone call to the appropriate part of the remote unit circuitry  120  for processing and prevents the incoming call from reaching the customer&#39;s telephone thereby preventing ringing of the customer&#39;s telephone.  
         [0096]    At the same time, the CPU  126  monitoring the ring circuit for a voltage drop which occurs when the customer picks up the handset of one of its telephones. Upon detecting the voltage drop, the CPU  126  immediately disconnects the telephone ring connection through the modem  130  and switches the connection to the customer&#39;s telephone thereby allowing the customer to make an outgoing call without interruption from the remote unit  34 .  
         [0097]    Referring now to FIG. 18, there is depicted the control program sequence for operation of the remote communication interface to the remote unit  34  and telephone service to the customer site  18 .  
         [0098]    As shown in FIGS. 1 and 8D, the customer site  18  is provided with a switch  300  which is embodied internally within a programmable modem circuit  302  shown in FIG. 8D. The programmable modem  302  executes a firmware control program which maintains the switch  300  in the normally closed position for normal telephone communication on the telephone network conductors to and from the customer&#39;s telephone(s)  304 .  
         [0099]    As shown in FIG. 8B, the tip and ring conductors of the telephone network are connected to a header or jack  306  which provides input connections to the modem  302  as shown in FIG. 8D. The switch  300 , shown in a pictorial representation in FIG. 1, is normally closed thereby providing a connection of the tip and ring circuits on leads  308  to the customer&#39;s telephone  304 . This is embodied in control step  310  in FIG. 18.  
         [0100]    The modem  302  is programmed to continuously monitor the ring voltage in step  312  to detect a voltage rise from the nominal ring voltage associated with a non-call condition. Such a voltage rise is an indication of an incoming telephone call on the ring conductor. Upon detecting a voltage rise in the ring conductor or circuit in step  314 , the modem  302  then looks at the following data signals to detect a communication signal header format indicating a data communication signal from the central site  10 . As noted above, this communication format can be the standard Internet TCP/IP communication protocol.  
         [0101]    If the data communication header format is not detected in step  316  following a detection of a voltage rise in step  314 , the modem  302  maintains the switch  300  in a closed position as shown in step  318  thereby allowing the normal incoming telephone call to be connected to the customer&#39;s telephone  304 . This allows the customer to conduct a normal two-way telephone call without interference from the remote unit  34 .  
         [0102]    Alternately, if the modem  302  detects the data communication header format in step  316 , the modem  302  opens the switch  300  in step  320  and establishes data communication between the central site  10  and the remote unit  34  in step  322 .  
         [0103]    The modem  302  continuously monitors the bidirectional data communication in step  324  to determine when the data communication is completed or finished. Upon completion of the data communication exchange, the modem  302  will reclose the switch  300  in step  326 .  
         [0104]    As shown in FIG. 18, continuously during the data communication sequence, the modem  302  monitors the ring voltage which has previously risen to a voltage peak during a telephone or data communication. If the customer picks up the handset of the telephone  304  during the data communication sequence, the ring voltage will drop. The modem  302 , by continuously monitoring the ring voltage in step  330  will detect the voltage drop from the voltage peak in step  332 . Immediately upon detecting a voltage drop in step  332 , the modem  302  terminates the data communication between the remote unit  34  and the central site  10  in step  334  and recloses the switch  300  in step  326  to enable the customer to complete the telephone call.  
         [0105]    The remote unit CPU will store a flag indicating that data communication was interrupted and will restart or reconnect the remote unit  34  with the central site at a later time or date to complete the data communication sequence which was interrupted.  
         [0106]    The same non-interruptible telephone service to the customer also applies when the processing unit  126  initiates a data communication to the central site  10 . The modem  302  will initiate a telephone call which will drive the ring voltage to a high voltage level. The processor in the modem  302  will continuously monitor the ring voltage during the data communication to and from the central site  10  to detect a voltage drop which will occur if the customer picks up the handset of the telephone  304 . In a manner similar to steps  330 ,  332 ,  334 , and  336  in FIG. 18 and described above, the processor in the modem  302  will immediately terminate data communication and reclose the switch  300  to enable the customer to complete a telephone call in a normal, non-interrupted manner. The processor of the modem  302  can supply a signal or flag to the processor  126  in the automatic meter reader  34  to indicate that data communication was interrupted. The automatic meter reader  34  will, at a later program time, reinitiate data communication to the central unit to retransmit all stored power values.  
         [0107]    Another communication feature is the use of global network communications via TCP/IP protocol through the modem  302 . This enables each remote customer site  18 ,  19 , etc., to exchange data with the central utility site  10  over a global network, such as the Internet  21 , in digitally encoded TCP/IP protocol at random time based intervals. The communication is two-way frequency programmable as well as duration programmable to permit communication flexibility. Each reader  34  will have an Internet address for unique communication with the central site  10 .  
         [0108]    The modem  302  at each customer use site as well as the modem in the central site  10  provides one way of connection to a global telecommunication network, such as the Internet or World Wide Web. It will be understood that other interfaces or connections to the global telecommunication network may also be employed, such as a direct cable connection, direct subscriber line connection, etc.  
         [0109]    Another communication feature is wireless communication via a cordless or wireless optical communications port  254 . An optical receiver, preferably an infrared receiver (IR) in the form of a pair of photodiodes or LED&#39;s  257  is mounted on the circuit board  66  and has a field of view through transparent cover  57  to receive optical or infrared signals from a wireless infrared programmer, not shown. The infrared programmer can be a hand held unit, computer lap top, or computer integrated infrared wand having an IR transmitter to enable a utility service person to program, upload and download information, connect and disconnect service via the disconnect switch  70 , and instantaneously obtain customer load profile, use and service interruption data.  
         [0110]    The photodiodes  257  are mounted on an integrated circuit  256  which carries connections to the ASIC circuit  255  for controlling the transmit and receive data communication through the photodiodes  257  at a clock rate established by a crystal oscillator  258  input to the ASIC circuit  255 . Input and output leads are connected between the ASIC circuit  255  and the central processor  126 . The CPU  126 , under stored program control, is capable of receiving and decoding input signals received by the photodiodes  257  as well as transmitting data in the desired format through one of the photodiodes  257  to the external programmer.  
         [0111]    The unique wireless communications port simplifies the construction of the remote unit  34  since a plug connection to an external programmer, as previously required, is no longer necessary.  
       Out-of-Spec Power  
       [0112]    As described above, an electric utility is required to deliver electrical power, particularly the voltage of such power, within a specified range of maximum and/or minimum voltages. For example, the supplied voltage cannot exceed 120 VAC RMS or be below 114 VAC RMS.  
         [0113]    [0113]FIG. 12 depicts an exemplary voltage versus time waveform of electrical power supplied to customer site  18 . TOD  1  depicts the start of an out of range voltage excursion on leg or phase one of the electric power delivered to the customer use site  18 . The remote unit  34  detects the out of range excursion of the instantaneous voltage on leg one beyond the high voltage limit, and stores the time of day (TODI) of the beginning of the out-of-spec voltage excursion as well as of the duration  301 , or the total length of time that the voltage is out-of-spec. This time duration is converted to kilowatt hours in real time as shown in FIG. 13 to provide an indication of the amount of out-of-spec power which was delivered to a particular use site.  
         [0114]    [0114]FIG. 12 also depicts a low voltage out-of-spec excursion. The start time TOD 2  and the duration  303  of this excursion are also detected and stored in the memory of the remote unit  34  and the kilowatt hours of low “out-of-spec” voltage is determined. In this manner, a utility can determine whether or not electric power was delivered to a particular use site outside of the required range.  
         [0115]    As shown in FIG. 13, when a upper RMS voltage limit is exceeded on any of the lines in step  305 , the CPU  126  monitors the RMS voltage for the duration of the upper limit excursion in step  306 . The CPU  126  via the EPLD  27  calculates the “out-of-spec” energy use during the upper limit excursion in step  308 . This “out-of-spec” energy use is accumulated in kilowatt hours in real time in step  310 . A similar sequence is used when the lower voltage RMS limit is exceeded in step  312 . As described above, the CPU  126  monitors the RMS voltage during the lower limit excursion in step  314  and calculates the total “out-of-spec” energy use in kilowatts below the legal voltage limit in step  316 . The out-of-spec low voltage and kilowatt hours are accumulated in real time in step  318  for transmission to the cental site  10  for billing purposes.  
       Power Demand Windows  
       [0116]    As describe above, the CPU  126  through the voltage and current detection circuitry  120  is capable of measuring and storing the instantaneous line voltages in the calculated KwH and other electric power parameters at each sample of the A/D converter  124 .  
         [0117]    The CPU  126  operates on a demand window concept wherein each 24 hour day is divided into a plurality of intervals of any predetermined duration, such as 15 minutes, 30 minutes, 45 minutes, 60 minutes, etc. In each interval, the total KwH, KAV, average phase angle, and peak voltage and current variables are calculated and stored in the memory  128 . This data can be transmitted to the central site at any time upon receipt of an interrogation signal from the central site  10  or on a time sequence initiated by the remote unit  34 .  
         [0118]    This interval arrangement allows peak voltage and current excursions on any of the power lines at a customer site to be detected and reported. Previously, the average of the voltage and current supplied to a particular customer site were used thereby rendering the central utility incapable of detecting any peak voltages or currents.  
         [0119]    As shown in FIG. 10, in order to provide different real time pricing for peak utility demand periods, week days, weekends, holidays, etc., the control program of the CPU  126  is provided with a plurality of discrete schedules, such as sixteen schedules by example only. Three of the schedules are shown in FIG. 10, again by example. The first schedule provides for regular time (non-daylight savings time) wherein the power usage data is stored and transmitted on a weekly basis. As shown in step  400 , the weekly data storage can also be subdivided into two different day schedules, one for week days and one for weekends. Up to twenty four windows per day are provided for each day schedule. At the end of any day schedule time period, the CPU  126  automatically switches to the other day schedule.  
         [0120]    Similarly, the CPU  126  is programmed to automatically switch to a daylight savings time schedule as shown in step  402 . This can also be on a weekly recurring data reporting basis. This schedule is divided into three days schedules, by example only, covering the weekdays, (Monday-Friday), a separate Saturday schedule and a separate Sunday schedule. Each day schedule is subdivided into twenty four windows per day, with the sequence automatically switching to the next sequential day schedule at the completion of the then current day schedule.  
         [0121]    Finally, a holiday schedule is depicted in step  404  which is provided on a daily basis.