Method and apparatus for controlling distributed electrical loads

• US 4,511,895 A
• Filed: 11/24/1981
• Issued: 04/16/1985
• Est. Priority Date: 10/30/1979
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Eichelberger, Charles W., Miller, Edward B.
• Primary Examiner(s): YUSKO, DONALD
• Application Number:
  US06/324,640
• Time in Patent Office: 1,239 Days
• Field of Search: 340/825.5, 340/825.52
• US Class Current: 370/462
• CPC Class Codes: H02J 13/00001 characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00018 using phone lines
• CPC Class Codes: H02J 13/00036 the elements or equipment being or involving switches, relays or circuit breakers circuits for indication of single switches H01H9/167
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/155 Coordinated control of two or more light sources
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/18 using switches, relays or circuit breakers, e.g. intelligent electronic devices [IED]
• CPC Class Codes: Y04S 10/40 Display of information, e.g. of data or controls
• CPC Class Codes: Y04S 20/246 the system involving the remote operation of lamps or lighting equipment

Abstract

An apparatus for controlling distributed electrical loads including a microprocessor based central controller coupled via a twisted pair bidirectional data line to a plurality of microcomputer based transceiver decoders. Each transceiver decoder is coupled to a plurality of relays, each relay associated with a particular load to be controlled. Override switches and sensors, coupled to transceiver decoders provide override requests and information related to ambient conditions at the site of a load. A user defined data base includes sub-sets of relays called sectors, patterns of relay states, remote switches, a time dependent schedule and condition responses. A communication protocall and arbitration scheme provide for interactive communication between the central controller and each transceiver decoder with interfacing with the operation of any other transceiver decoder. Enhanced data storage capacity is achieved through dynamic allocation of memory space for pattern data.

Claims

1. Apparatus at plural remote locations permitting non-interfering randomly occurring digital data communication between plural locations via a common data communications link, said apparatus being situated at each of said plural locations and comprising:

data transmitting means for serially transmitting digital binary bit information conveying signals having first and second states onto said communications link as described, one of said first and second states being dominant when transmitted on said link even if simultaneous transmission of the other state on the same link is attempted from another location, said binary bit information conveying signals including unique duration or sequence patterns of said first and second states identifying respective ones of a plurality of output modes of said data transmitting means, said

arbitatration means for monitoring the existence of and first and second states on the link during the time required for the transmission of said binary bit of information, for comparing the state value then being transmitted from its respective remote location with the state value then existing on said link, and for inhibiting further transmission of the data onto said link by its respective data transmission means if there is a difference between the value then being transmitted and the actual state then existing thus eventually leaving only one remote location transmitting on said link.

2. Apparatus as in claim 1 wherein:

said communication link comprises two electrical conductors, and said first and second states comprise high and low impedance states respectively between said conductors.

3. Apparatus as in claim 1 wherein:

said communication link is a bi-directional data communication channel.

4. Apparatus as in claim 1, 2 or 3 wherein said information conveying signals comprise width modulated pulses of electrical signals where the two binary values are represented by different pulse widths occurring as required to represent desired data values within successive bit cells or time periods.

5. Apparatus as in claim 4 wherein said bit cells or time periods have varying total time durations corresponding respectively to the binary value encoded therein.

18. Apparatus according to claim 1 further including access means for monitoring the busy or free status of said communication link for inhibiiting access thereto from a remote location unless a free status exists.

6. In a programmable system for controlling plural distributed electrical loads including plural relays, each connected to control a respectively corresponding one of said plural distributed electrical loads;

plural remotely located transceiver decoder circuits all connected in common to a data link for controlling a predetermined subset of said relays in response to received data signals and for transmitting data signals relating to such control onto said data link; and

a programmable central controller connected to provide said received data signals to each of said transceiver decoders via said data link;

the improvement comprising;

access means at each transceiver decoder site for monitoring the busy or free status of said data line and for inhibiting initial transmitting access thereto from the respectively associated transceiver decoder unless a free status exists;

data transmitting means within each transceiver decoder for serially transmitting digital binary bit information conveying signals having first and second states onto said data link as desired only if permitted by said access means, one of said first and second states being dominant when transmitted on said link even if simultaneous transmission of the other state on the link is attempted by another transceiver decoder; and

arbitration means at each transceiver decoder site for monitoring the existence of said first and second states on the link during the time required for the transmission of each binary bit of information, for comparing the state value then being transmitted from its respective transceiver decoder with the state value then existing on said link, and for inhibiting further transmission of data onto said link by its respective said data tansmission means if there is a difference thus eventually leaving only one transceiver decoder in communication on said link and doing so without interferring with the communication from said one transceiver decoder.

7. An improvement as in claim 6 wherein:

said data link comprises two electrical conductors, and

said first and second states comprise high and low impedance states respectively between said conductors.

8. An inprovement as in claim 6 wherein said data link is a bi-directional data communication channel.

9. An improvement as in claim 6 wherein central processor controls a relays in at least one pre-programmed time-dependent sequence.

10. An improvement as in claim 6, 7, 8 9 wherein said information conveyng signals comprise width modulated pulses of electrical signals where the two binary values are represented by different pulse widths occurring as required to represent desired data values within successive bit cells or time periods.

11. An improvement as in claim 10 wherein said bit cells or time periods have varying total time durations corresponding respectively to the binary value encoded therein.

12. Apparatus at plural remote locations permit non-interferring randomly occurring digital data communication between plural remote locations via a common data communication link, said apparatus being situated at each of said plural remote locations and comprising:

access means for monitoring the busy or free status of said communication link for inhibiting initial access thereto from its respective remote location unless a free status exists,

data transmitting means for serially transmitting digital binary bit information conveying signals having first and second states onto said communications link as desired only if permitted by said access means, one of said first and second states being dominant when transmitted on said link even if simultaneous transmission of the other state on the same link is attempted from another remote location,

arbitration means for monitoring the existence of said first and second states on the link during the time required for the transmission of each binary bit of information, for comparing the state value then being transmitted from its respective remote location with the state value respective remote location with the state value then existing on said link, and for inhibiting further transmission of data onto said link by its respective said data transmission means if there is a difference thus eventually leaving only one remote location in communication on said link and doing so without interferring with the communication from said one remote location, and

wherein said information conveying signals comprise width modulated pulses of electrical signals where the two binary values are represented by different pulse widths in said first state as required to represent desired data values within successive bit cells or time periods, each such width modulated pulse being separated from the next such pulse by a period of said second state, said period of said second state providing said apparatus at each of said plural locations time to process the preceding information bit.

13. Apparatus as in claim 12 wherein said period of said second state is of a fixed duration thereby making the total time required to tansmit a binary bit of information vary as a function of the information value being transmitted.

14. Apparatus as in claim 13 wherein said communication link comprises two electrical conductors, and said first and second states comprise high and low impedance states respectively between said conductors.

15. Apparatus at plural remote locations permitting non-interfering randomly occuring bi-directional digital data communication via a common communication channel between a master apparatus and a plurality of master/slave apparatuses, said apparatus comprising:

master apparatus operating in a master mode wherein it can access the common communication channel whereever free and without regard to any predetermined time schedule, said apparatus being adapted to transmit master and slave mode commands to a master/slave apparatus;

means for receiving and decoding a data signal on said communication channel, said digital data signal including a command for a master/slave apparatus to operate either in said master mode or in a slave mode; and

means for inhibiting transmitting access to said communication channel for a predetermined period of time in response to a slave mode command from said master apparatus.

16. Apparatus according to claim 15 wherein said communication channel is bi-directional.

17. Apparatus according to either of claims 15 or 16 wherein said master and slave mode commands are width modulated pulses.