Method and apparatus for controlling distributed electrical loads

• US 4,656,475 A
• Filed: 05/01/1985
• Issued: 04/07/1987
• Est. Priority Date: 10/30/1979
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Miller, Edward B., Eichelberger, Charles W.
• Primary Examiner(s): YUSKO, DONALD
• Application Number:
  US06/729,425
• Time in Patent Office: 706 Days
• Field of Search: 340/825.5, 340/825.51, 340/825.06, 370/61, 370/79, 370/94, 370/108, 371/32, 371/69
• 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 13/00016 using a wired telecommunication network or a data transmission bus
• 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 bi-directional 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. In a control arrangement having apparatus at plural locations permitting non-interfering asynchronously initiated digital data communication between plural apparatus via a common data communication link, said apparatus being situated at each of said plural locations, a method for communicating among said plural locations comprising the steps of:

monitoring, by access means, the busy or free status of said communication link,

inhibiting initial access thereto from an apparatus unless a free status exists,

serially transmitting, by data transmitting means within an apparatus, digital binary bit information conveying width modulated pulses of electrical signals having first and second states onto said communications link as desired only if said communication link is in free status as monitored by said access means, one of said first and second states being dominant when transmitted on said link even it simultaneous transmission of the other state on the same link is attempted from another remote location, 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,

monitoring, by arbitration means, the existence of said first and second states on the link during the time required for the transmission of each binary bit of information,

comparing the state value then being transmitted from its respective remote location with the state value then existing on said link, and

inhibiting further transmission of data onto said link by its respective said data transmission means is there is a difference between the value then being transmitted and the actual state then existing thus eventually leaving only one apparatus transmitting on said link.

2. A method according to claim 1 wherein said step of comparing includes comparing the impedance state value then being transmitted from its respective remote location with the impedance state value then existing on said link.

3. 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 sub-set of 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 signal to each of said transceiver decoders via said data link;

a method for arbitrating conflicting communication among said plural remotely located transceiver decoder circuits comprising the steps of;

monitoring, by access means at each transceiver decoder, the busy or free status of said data line;

inhibiting initial transmitting access thereto from the respectively associated transceiver decoder unless a free status exists,

serially transmitting, by data transmitting means within each transceiver decoder, digital binary bit information conveying width modulated pulses of electrical 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, 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;

monitoring, by arbitration means at each transceiver decoder site, the existence of said first and second states on the link during the time required for the transmission of each binary bit of information,

comparing the state value then being transmitted from its respective transceiver decoder with the state value then existing on said link, and

inhibiting further transmission of data onto said link by its respective said 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 transceiver decoder in communication on said link by its respective said data transmission means and doing so without interferring with communication from said one transceiver decoder.

4. A method according to claim 3 wherein said step of comparing includes comparing the impedance state value being transmitted from its respective transceiver decoder with the impedance state value then existing on said link.

5. In 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 sub-set of said relays in response to received data signals and for transmitting data signal relating to such control onto said data link; and

a programmable central controller for normally controlling said relays in at least one preprogrammed time-dependent sequence, said controller connected to provide said received data signals to each of said transceiver decoders via said data link;

a method for arbitrating conflicting communication among said plural remotely located transceiver decoder circuits comprising the steps of;

monitoring, by access means at each transceiver decoder, the busy or free status of said data line,

inhibiting initial transmitting access thereto from the respectively associated transceiver decoder unless a free status exists,

serially transmitting, by data transmitting means within each transceiver decoder, digital binary bit information conveying width modulated pulses of electrical 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, where the two binary values are represented by different pulse widths occurring as required to represent desired data values within successive bit cells of time periods;

monitoring, by arbitration means at each transceiver decoder site, the existence of said first and second states on the link during the time required for the transmission of each binary bit of information,

comparing the state value then being transmitted from its respective transceiver decoder with the state value then existing on said link; and

inhibiting further transmission of data onto said link by its respective said 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 transceiver decoder in communication on said link and doing so without interfering with the communication from said one transceiver decoder.

6. In a control arrangement having apparatus at plural remote locations permitting non-interfering randomly occurring digital data communcation between plural remote locations via a common data communication link, said apparatus being situated at each of said plural remote locations, a method for arbitrating conflicting communications along said plural apparatus comprising the steps of:

serially transmitting, by data transmitting means, digital binary bit information conveying signals having first and second states onto said communications link as desired, 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, said signals being 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,

monitoring, by arbitration means, the existence of said first and second states on the link during the time required for the transmission of each binary bit of information,

comparing the state value then being transmitted from its respective remote location with the state value then existing on said link, and

inhibiting further transmission of data onto said link by its respective said data transmission means is there is a difference thus eventually leaving only one remote location in communication on said link and doing so without interfering with the communication from said one remote location.

7. A method according to claim 6 further including the steps of:

monitoring by access means the busy or free status of said communication link; and

inhibiting initial access thereto from a remote location unless a free status exists.

8. A method according to claim 6 wherein said step of serially transmitting includes serially transmitting width modulated pulses wherein said period of said second state is of a fixed duration thereby making the total time required to transmit a binary bit of information vary as a function of the information value being transmitted.

9. A method according to claim 6 wherein said step of comparing includes comparing the impedance state value then being transmitted from its respective remote location with the impedance state value then existing on said link.