|Publication number||USRE41739 E1|
|Application number||US 11/510,862|
|Publication date||Sep 21, 2010|
|Filing date||Aug 25, 2006|
|Priority date||Sep 6, 2000|
|Also published as||US6734784, US6784790|
|Publication number||11510862, 510862, US RE41739 E1, US RE41739E1, US-E1-RE41739, USRE41739 E1, USRE41739E1|
|Inventors||Marshall E. Lester|
|Original Assignee||Powerline Control Systems, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (24), Referenced by (2), Classifications (25), Legal Events (11)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention is a continuation-in-part of my prior application Ser. No. 09/656,160 entitled “POWERLINE PULSE POSITION MODULATED COMMUNICATION APPARATUS AND METHOD”, filed Sep. 6, 2000.
This invention is directed to an apparatus which enables digital communication between two or more devices wherein the devices are connected to the same powerline and use the same powerline to receive power and as a physical channel for electronic intercommunication.
There are devices which are more conveniently used if they can be remotely controlled. In a household, such devices are mostly appliances and lighting loads. The appliances and lighting loads may be remotely controlled for a number of different reasons. For example, for night security, some lights may be controlled by a timer. In other cases, different lighting intensity and different lighting distribution may be desirable in a single room, depending upon its use. The room may be used for reading, conversation or watching displays, such as television. Each suggest a different lighting level and different lighting distribution. Normally, people do not make such changes because it is inconvenient to do so. Unless there is a convenient way to accomplish it, such adjustment of the lighting system is rarely done. Therefore, it is desirable to have a convenient, reliable way to remotely control lighting systems.
In addition to lighting systems, other devices can be conveniently remotely controlled. For example, powered gates and garage doors can be remotely controlled. An electric coffee pot may be turned on at an appropriate morning hour. Powered draperies may be opened and closed, depending upon sun altitude.
As electronic technology has advanced, inventors have produced a variety of control systems capable of controlling lighting and other electric loads. In order to be useful as a whole-house lighting control system, there are certain requirements that must be met. A system must permit both small and large groups of lights to be controlled on command. The problem is the connection between the controller and the lighting load. Such connection may be hard-wired, but such is complex and very expensive to retrofit into an existing home. Another connection system may operate at radio frequency, but this has proven difficult to implement because the FCC requires low signal levels which are subject to interference and because the transmission and receiving circuitry is complex and expensive.
It must be noted that both the controller and the load to be controlled are connected to the same powerline. It would be useful to use the powerline as the communication-connecting channel. Prior powerline communication schemes have had difficulties employing the powerline as a communication channel because the communication signals after being attenuated by the powerline circuitry are very small compared to the background noise. It is impossible to avoid the fact that between certain locations in a residence there will be very high attenuation of any transmitted signals. It has been difficult to reliably separate the highly attenuated communication signals from the background noise on the powerline.
The situation is further aggravated and complicated by the fact that the noise and attenuation parameters are constantly and unpredictably changing as loads are connected and disconnected both inside the primary residence and inside any of the many neighboring residences attached to the same mains power transformer. In reality the powerline circuit used for communication in a residence includes all the residences attached to the mains power transformer. There is no practical way to avoid the complications caused by this fact.
In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed a powerline pulse position modulated communication apparatus and method. The transmitting portion of the apparatus senses the zero voltage crossing point in the powerline and transmits a series of signal pulses at a set of specified positions, the position of the data pulse relative to the starting reference pulses representing digital data in the form of a digital number. The set of all possible relative positions is in the quiet zone adjacent, but spaced from the main voltage zero crossing point. The receiving circuit also senses the voltage zero crossing point and can reliably detect the signal pulse in the background powerline noise because of the knowledge of where the signal pulse is expected in the quiet zone adjacent, but away from the zero crossing point and because of the high magnitude of the very robust signal pulse even after significant residential attenuation. After determining in which one of the possible relative positions the signal pulse was located, the associated digital data in the form of a digital number is easily determined. Thus digital data is communicated from one device through the powerline to another device using this method of powerline pulse position modulation.
It is a purpose and advantage of this invention to provide a method and apparatus for reliable communication of digital data over the powerline by means of a powerline pulse position modulation communication method.
It is a further purpose and advantage of this invention to provide a method and apparatus for powerline pulse communication wherein the voltage zero crossing is sensed and the communication signal pulse is transmitted and sensed in a receiver based on the signal position relative to the starting point of the previous pulse.
It is a further purpose and advantage of this invention to provide a method and apparatus by a powerline pulse position modulation communication method for the purpose of remote electrical load control.
It is a further purpose and advantage of this invention to provide a method and apparatus wherein the voltage zero crossing is sensed, and digital pulse windows are defined with respect to the zero voltage crossing, but spaced from the zero voltage crossing so as not to interfere with zero voltage crossing equipment.
It is a further purpose and advantage of this invention to provide a method and apparatus by a powerline pulse position modulation communication method for the purpose of remotely retrieving operational data from residential appliances.
It is a further purpose and advantage of this invention to provide a method and apparatus by a powerline pulse position modulation communication method for the purpose of remotely controlling residential loads for utility company energy management.
It is another purpose and advantage of this invention to provide a powerline pulse position modulated communication apparatus and method which complies with FCC regulations relating to apparatus which is connected to and communicating on the powerline.
The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description, taken in conjunction with the accompanying drawings.
The purpose of the powerline pulse position modulated communication apparatus of this invention as shown in
Lighting Control System
A lighting control system as shown in FIG. 2 and
Also connected to the powerline 18 and neutral 14 are lighting load receiving controllers 20, 22 and 24. These receiving controllers are respectively connected to loads 26, 28 and 30. The loads are electric lights, in this example, but may be heater or motor loads as described above. Furthermore, the receiving controllers 20, 22 and 24 are capable of receiving digital commands which change the supply of power to the loads and may supply different levels of power to the loads to control the brightness of the lighting load. The transmitting controller 10 emits its digital commands into the powerline 18 for transmission to the receiving controllers 20, 22 and 24 by pressing one or more of the command buttons 32, 34 and 36 on transmitting controller 10. Thus, the receiving controllers 20, 22 and 24 receive digital commands from the transmitting controller 10 to control the loads 26, 28 and 30, respectively. No separate wiring or radio frequency communication is required, but the transmitting controller places signals in the powerline 18. Such transmitted signals are coded so that they can be detected by all of the receiving controllers.
A similar arrangement is seen in
In addition, transmitting master controller 44 is connected to the powerline. It is identical to the transmitting controllers 10, 38, 40 and 42, but it is programmed differently to send out digital data signals which command receiving controllers to control their loads individually. The fact that transmitting controller 44 is connected only between powerline 18 and neutral 14 does not interfere with its ability and function to send signals to receiving controllers connected between powerline 16 and neutral 14.
Transmission and Receiving Circuit Operation
The transmitting controllers 10 and the receiving controllers 20 are identical, in the sense that they contain the same transmitting and receiving circuitry. They are programmed differently so as to achieve the desired different results. The controller 10 is schematically illustrated in FIG. 1. It has a transmitting circuit 46, which is connected to powerline 16 through line 48 and to neutral through line 49. The transmitting circuit comprises triac 50 which is connected in series with energy storage capacitor 52. Inductor 54 is also in the series connection between line 48 and capacitor 52. Capacitor 56 forms a low pass filter with inductor 54 to minimize high frequency emissions so that the transmitter meets the FCC requirements. Triac 50 is controlled by line 58 which is the output from digital control integrated circuit 60. Hereinafter, the conventional abbreviation “IC” will be used in place of the term “integrated circuit.” When the digital control IC sends an appropriate firing signal on line 58, the triac fires and puts a pulse in line 16 with respect to the neutral 14.
Controller 10 also contains a receiver circuit 62. The important components of the receiver circuit 62 form a band pass filter circuit. This includes capacitor 66, capacitor 68, capacitor 76, inductor 70, inductor 74 and inductor 64. Resistor 72 limits the current through the circuit. Resistor 78 is connected in series to limit the current in signal line 80. This circuit filters the signal pulse out of the powerline 60 cycle voltage and background noise.
Signal line 80 is connected into digital control IC 60 as its signal input. As a particular example, digital control IC 60 is a microprocessor Microchip model PIC16C622. The input signal line 80 is connected between two clipping diodes 82 and 84 to protect the digital control IC 60 from excessively high and low voltages. The signal input line 80 is connected to comparator 86 where the signal voltage is compared to internal voltage reference 88. The voltage reference 88, which is adjustable by the digital control IC 60 allows the digital control IC 60 to automatically adjust the receiving signal level to be set above the noise level. This is a form of automatic gain control which is essential so that the digital control IC 60 can discriminate between noise and real signal pulses. The comparator output 90 carries the received digital signal to the internal processing circuitry of the digital control IC.
There are additional inputs to the digital control IC 60. Zero crossing detector 92 is connected to powerline 16 and neutral 14. It has an output to the digital control IC 60. Power supply 94 supplies power to the digital control IC and to the EEPROM memory 96. There may be a plurality of the input switches, one of which is indicated at 98, for causing the digital control IC 60 to perform some internal operation or to issue transmitted commands. The commands of switch 98 correspond to the command buttons 32, 34 and 36 seen in FIG. 2. It is desirable that there be some method of visual feedback to the user for a variety of programming and control uses. This is provided by indicator light 100, which may be energized by the digital control IC 60. When the controller 10 is acting as a receiver load controller, it has an output circuit which controls the load. This output device 102 is in the form of a relay, triac, or the like. It controls the flow of power from line 16 to the load 104.
Pulse Position Modulation of Digital Data
In the current embodiment of the invention the first two pulses in any message are special reference pulses placed in predetermined fixed positions. These reference pulses do not encode any data. All following data pulses are referenced as to the reference pulse positions.
Each pulse after the first two synchronization pulses represents one transmitted data number. The number transmitted can range from 1 to N where N is the total number of possible positions of one pulse. In
In order that the receiver may know the exact position of the signal pulses relative to the transmitter, a pair of start pulses or reference pulses is transmitted at the beginning of each series of data pulses, see FIG. 9. These two pulses will be referred to as reference pulses or Reference A and Reference B pulses. These reference pulses do not carry data but serve to establish a reference time for the determination of the position of the following data pulses.
The reason there are two reference pulses is that the pulses generated by discharging a positively charged capacitor appear differently to the receive circuit and digital control IC than the pulses generated by discharging a negatively charged capacitor.
Because the receive circuit only can sense positive voltage only, relative to ground, only the positive pulses such as 222, 224 and 228 can be sensed. An example is positive pulse 204 shown in FIG. 10.
The same logic applies to pulses of Type B where the first wave 230 is negative and the second wave 228 is positive. Only the second wave 208 can be sensed by the comparator. This pulse at 228, 230, 208, and 210 is called a Type B pulse and if it is a Reference pulse it is called Reference B Pulse.
This phenomenon leads to the fact that on positive half cycles the receive circuit senses the first wave of a pulse, and on the negative half cycles the receive circuit senses the second wave of a pulse. The time difference caused by this phenomenon produces a fixed offset in the time of pulse arrival sensed by the digital control IC that is equal to the width of the first wave. Since this offset is stable and fixed it is very simple for the digital control IC to measure this difference and then compensate for it throughout the series of data pulses.
This phenomenon is shown as a 10uS difference in FIG. 10. The two reference pulses are transmitted by the transmitter at exactly 8333uS apart so that he receiver can measure the difference between the received pulses. This difference or offset remains the same throughout the transmission, appearing as a fixed offset on every other half cycle.
When a powerline pulse is desired, the first need is to charge the capacitor 52 in FIG. 1. Before the initial charging the initial charge stale of the capacitor 52 is unknown. The digital control IC puts an initial trigger pulse 106, see
It is the position of the data pulse relative to the reference pulse, which determines what digit has been encoded in that pulse. In the example in
Because only one pulse can be produced every half cycle, the pulse may be placed in only one of the sixteen positions. If there are 16 possible positions then one and only one of the digits 0 to 15 may be encoded by the position of the pulse. If the pulse is located in position #3 as shown as 134 cycle T7 in
The two pulses 130 and 132 in cycles T5 and T6 are the reference pulses and are both located in position 0. Because they are used to establish the reference points for all following data pulses, there position is by definition position number 0.
Since only one pulse can be transmitted per half cycle with this circuit design, one and only one number can be transmitted each half cycle. The reason this method of modulating data is called “pulse position modulation” herein is because the value of the data is encoded in the position of the pulse.
Because of attenuation, background noise, and other periodic and intermittent random pulses present on the powerline, these signal pulses would ordinarily be difficult to detect. However, in accordance with this invention, when the pulse is located near the zero voltage crossing point for the power voltage wave, there is a quiet zone in the powerline voltage waveform in which the signal pulse can be more reliably detected.
To summarize, there are four primary reasons the area from 1000 uS to 500 uS before zero crossing is selected for our transmission period. First, because a relatively large pulse is generated because the capacitor is charged to a large voltage. Second, because there is a relatively uniform voltage from the beginning of this period to the end of this period. Third, because there is little interference caused by the communication pulses to devices that utilize the powerline zero crossing for various purposes, such as clocks or light dimmers. Fourth, because there is very little noise from pulse producing devices, such as light dimmers, during this period.
The manner of operation of this receiving circuit 62 in
These times, shown as X1 and X2, which are the positions of the two starting reference pulses, are placed at the beginning of the quiet zone and define for the following data pulses the reference position. The reference pulse 150 is timed from the previous zero crossing 105 and is set to be about 1024 microseconds before the next zero crossing 107. Since it is not desired to use the about 500 microseconds before zero crossing 107, that space is left free of signals.
These times, shown as X3 and X4 in
The method of calculating the data from the time period after which a data pulse follows a reference pulse is very straightforward. For example the pulse 142 follows the reference pulse 130 by the time X7. If the reference pulse 130 is in data position 0 then the data encoded in pulse 142 is (X7−3*16666 msec)/32 msec. This is assuming the data positions are each 32 msec wide.
This is the fundamental method of transmitting and receiving numerical data. This series of numerical data is stored in the Digital control IC and processed according to the application program requirements. If the device is a lighting controller, the data would most likely represent lighting system addresses and command instructions. Other applications would have other meanings for the decoded data. Some application devices such as a powerline modem might use the invention for pure communication of data and may not have a specific application function.
This invention has been described in its presently contemplated best embodiment, and it is clear that it is susceptible to numerous modifications, modes and embodiments within the ability of those skilled in the art and without the exercise of the inventive faculty. Accordingly, the scope of this invention is defined by the scope of the following claims.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3689886 *||Feb 9, 1971||Sep 5, 1972||Thomas Industries Inc||Control system having transmitter-receiver sets for operating functional device over power lines|
|US4060735 *||Jul 12, 1976||Nov 29, 1977||Johnson Controls, Inc.||Control system employing a programmable multiple channel controller for transmitting control signals over electrical power lines|
|US4218655 *||Dec 14, 1977||Aug 19, 1980||New England Power Service Company||Method and apparatus for transmitting intelligence over a carrier wave|
|US4264960 *||Jul 2, 1979||Apr 28, 1981||Sangamo Weston, Inc.||System for controlling power distribution to customer loads|
|US4291236 *||Jun 29, 1979||Sep 22, 1981||Sangamo-Weston, Inc.||Remote receiver for load and rate control in a power transmission system|
|US4300126 *||Apr 11, 1980||Nov 10, 1981||General Electric Co.||Method and apparatus, for power line communications using zero crossing load interruption|
|US4328482 *||Jan 21, 1981||May 4, 1982||Consumer Electronic Products Corporation||Remote AC power control with control pulses at the zero crossing of the AC wave|
|US4329678 *||Mar 24, 1980||May 11, 1982||Hatfield Jerry M||Method and apparatus for remotely controlling an electrical appliance|
|US4367455 *||Feb 12, 1981||Jan 4, 1983||Morton Fried||Powersaving room security system|
|US4398178 *||Apr 3, 1980||Aug 9, 1983||Handelsbolaget Light Regulation||Apparatus for transmitting information on an alternating current line|
|US4400688 *||Oct 15, 1980||Aug 23, 1983||New England Power Service Company||Method and apparatus for communication over electric power lines|
|US4567511 *||May 24, 1984||Jan 28, 1986||Agb Research Plc||Transmitting and storing data relating to television viewing|
|US4658241 *||Sep 17, 1985||Apr 14, 1987||Allied Corporation||Surveillance system including transmitter and receiver synchronized by power line zero crossings|
|US4716409 *||Jul 16, 1986||Dec 29, 1987||Homestead Products, Inc.||Electrical appliance control system|
|US4996513 *||Feb 20, 1990||Feb 26, 1991||Emerson Electric Co.||Carrier stability erasure filling system for communications over electricity distribution network|
|US5005187 *||Mar 23, 1989||Apr 2, 1991||Pico Electronics Limited||Remote control|
|US5007042 *||Sep 8, 1989||Apr 9, 1991||Santi Larry D||Method and apparatus for transmitting analog data embedded in a digital pulse train|
|US5264823 *||Nov 2, 1992||Nov 23, 1993||Motorola Lighting, Inc.||Power line communication system|
|US5614811 *||Sep 26, 1995||Mar 25, 1997||Dyalem Concepts, Inc.||Power line control system|
|US5691691 *||Jan 6, 1997||Nov 25, 1997||Motorola, Inc.||Power-line communication system using pulse transmission on the AC line|
|US5748671 *||Dec 29, 1995||May 5, 1998||Echelon Corporation||Adaptive reference pattern for spread spectrum detection|
|US5920253 *||Sep 5, 1995||Jul 6, 1999||Laine; Seppo||Local area method arrangement|
|US6496104 *||Mar 14, 2001||Dec 17, 2002||Current Technologies, L.L.C.||System and method for communication via power lines using ultra-short pulses|
|US20040101312 *||Aug 18, 2003||May 27, 2004||Florencio Cabrera||AC power source light modulation network|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8716882||Jul 26, 2012||May 6, 2014||Powerline Load Control Llc||Powerline communicated load control|
|US9544017||Feb 28, 2014||Jan 10, 2017||Powerline Load Control Llc||Powerline communicated load control|
|U.S. Classification||375/239, 340/310.11, 375/259, 340/310.16, 340/310.17, 340/310.14, 340/310.12, 340/12.32|
|International Classification||H04M11/04, H02J13/00, H03K7/04, H03K7/06, H03K9/04, H03K9/06|
|Cooperative Classification||Y02E60/783, H05B37/0263, H02J13/0037, H02J13/0034, H02J13/0051, Y04S40/123, Y02B70/3283, Y04S20/246|
|European Classification||H02J13/00F4B2F2, H02J13/00F4B2B2B4, H02J13/00F4B2B2B2|
|Oct 14, 2009||AS||Assignment|
Owner name: VALLEY ECONOMIC DEVELOPMENT CENTER, INC., CALIFORN
Free format text: SECURITY AGREEMENT;ASSIGNOR:POWERLINE CONTROL SYSTEMS, INC.;REEL/FRAME:023364/0750
Effective date: 20090824
|Aug 16, 2010||AS||Assignment|
Owner name: CITY OF LOS ANGELES, CALIFORNIA
Free format text: SECURITY AGREEMENT;ASSIGNOR:POWERLINE CONTROL SYSTEMS, INC.;REEL/FRAME:024838/0108
Effective date: 20100803
|Apr 16, 2012||REMI||Maintenance fee reminder mailed|
|Sep 2, 2012||REIN||Reinstatement after maintenance fee payment confirmed|
|Sep 2, 2012||LAPS||Lapse for failure to pay maintenance fees|
|Sep 20, 2012||FPAY||Fee payment|
Year of fee payment: 8
|Sep 20, 2012||SULP||Surcharge for late payment|
|Jun 3, 2013||PRDP||Patent reinstated due to the acceptance of a late maintenance fee|
Effective date: 20100921
|Apr 8, 2016||REMI||Maintenance fee reminder mailed|
|Apr 11, 2016||FPAY||Fee payment|
Year of fee payment: 12
|Apr 11, 2016||SULP||Surcharge for late payment|
Year of fee payment: 11