Programmable electronic real-time load controller providing for adaptation of load control in response to varying environmental conditions

• US 4,354,241 A
• Filed: 12/27/1979
• Issued: 10/12/1982
• Est. Priority Date: 12/27/1979
• Status: Expired due to Term

• Current Assignee: Butler Manufacturing Company (Bluescope Steel Limited)
• Original Assignee: Butler Manufacturing Company (Bluescope Steel Limited)
• Inventors: Barello, Lawrence J.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US06/107,554
• Time in Patent Office: 1,020 Days
• Field of Search: 364/492, 364/493, 364/506, 364/101, 307/35, 307/39, 307/38, 307/41, 340/147 R
• US Class Current: 700/296
• CPC Class Codes: G05D 23/1917 using digital means

Abstract

A programmable electronic real-time load controller includes: a plurality of load control circuits, each being adapted to be interconnected with a load; a hardware clock; and a data processor for executing a set of program instructions stored in a program memory to effect real-time control of the load control circuits by comparing real-time information from the hardware clock with a time schedule stored in an event memory of the data processor. The time schedule is in the form of one or more control events and corresponding event times for each load, with each control event representing a period of time during each predetermined control interval subsequent to its corresponding event time that a load is to be on. In order to permit the controller to adapt the time schedule to varying environmental conditions, the controller is provided with additional components including a second program memory, at least one indoor temperature sensor, and an outdoor temperature sensor. Environmentally-adaptive modifications to real-time control include: an advance start modification, in which an event time associated with a load is advanced in relation to the deviation of outdoor temperature from a first reference temperature; a duty-cycle shift modification, in which the on-time of a load currently being duty-cycled in real-time is increased in relation to the deviation of indoor temperature from a second reference temperature; and, a night setback modification, in which a load is turned on whenever indoor temperature is outside predetermined high and low limits. Provision is made for effecting analog-to-digital conversion of the temperatures; for selecting any load for each of the various modifications; for grouping the loads at the facility into first and second zones, and by providing an indoor temperature sensor for each zone; for selecting the value of a zone deadband for the duty-cycle shift modification; and, for selectively displaying information related to real-time control, or, the various indoor and outdoor temperatures and an advance time computed in the advance start modification.

Claims

1. An electronic controller for controlling the energization states of a plurality of electrical loads, said controller comprising:

a plurality of load control circuits, each said load control circuit being adapted to be interconnected with a load, and having a load-on state when its load is to be on, and a load-off state when its load is to be off;

clock means for determining real-time;

sensor means for sensing at least one environmental temperature at a facility at which the plurality of electrical loads are located;

event memory means storing a time schedule for real-time control of the plurality of electrical loads;

program memory means storing a set of program instructions; and

,

program means responsive to said set of stored program instructions for;

obtaining said time schedule from said event memory means;

obtaining a sensed environmental temperature from said sensor means;

modifying said time schedule in accordance with said sensed environmental temperature;

obtaining real-time from said clock means; and

,

placing said load control circuit for each load in said load-on and said load-off states by comparing said real-time with said modified time schedule.

2. A controller as recited in claim 1, wherein said event memory means includes a plurality of event memory, locations having stored therein one or more control events and corresponding event times for each load, each said control event representing a period of time during each predetermined control interval subsequent to its corresponding event time that a load is to be on, said control events further representing an on control function in which a load is to be on for the entirety of each control interval, an off control function in which a load is to be off for the entirety of each control interval, and, a duty-cycle control function in which a load is to be on for a predetermined portion of each control interval.

3. A controller as recited in claim 2, wherein said processing means is operative to modify at least one event time associated with a load in accordance with said sensed environmental temperature.

4. A controller as recited in claim 3, wherein said sensor means is adapted to sense outdoor temperature at the facility;

and, wherein said processing means is operative to implement an advance start modification of said time schedule by advancing said at least one event time in relation to the deviation of said sensed outdoor temperature from a predetermined reference temperature.

5. A controller as recited in claim 4, further comprising means for selecting any load of the plurality of electrical loads for said advance start modification;

and, wherein said processing means is operative to implement said advance start modification only for those loads that have been selected therefor.

6. A controller as recited in claim 5, wherein said means for selecting comprises a manually-actuable switch for each load;

and, wherein said processing means is operative to interrogate each said manually-actuable switch to determine those loads that have been selected for said advance start modification.

7. A controller as recited in claim 4, wherein said processing means is operative to determine an advance time, which represents the amount of time by which said at least one event time is advanced under said advance start modification, as a linear function of the deviation of said sensed outdoor temperature from said reference temperature.

8. A controller as recited in claim 7, wherein said processing means is operative to determine said advance time only if said deviation is equal to or greater than a predetermined deadband.

9. A controller as recited in claim 8, wherein said processing means is operative to determine said advance time as a first linear function of said deviation when said sensed temperature is above said deadband, and to determine said advance time as a second linear function of said deviation when said sensed temperature is below said deadband.

10. A controller as recited in claim 9, further comprising means for selecting a first advance gain and means for selecting a second advance gain;

and, wherein said processing means is operative to obtain said first and said second advance gains from said selecting means therefor, to vary the slope of said first linear function in proportion to said first advance gain, and to vary the slope of said second linear function in proportion to said second advance gain.

11. A controller as recited in claim 10, wherein said first and said second linear functions each comprise the relationship ##EQU4## if |TOD-TRFAS|≧

Deadband where;

AT=said advance time

TOD=said sensed outdoor temperature

TRFAS=said reference temperature

|TOD-TRFAS|=the absolute value of said deviation

G=said first advance gain, for said first linear function, and said second advance gain, for said second linear function

C=a first contant

K=a second constant.

12. A controller as recited in claim 7, further comprising storage means, said storage means having a plurality of storage locations, each said storage location being associated with one of the plurality of electrical loads;

and, wherein;

said real-time in said clock means represents elapsed time from the beginning of a week;

said event memory locations in said event memory means are grouped by load, and, within each said load group, by day;

said processing means is operative to;

sum said real-time with said advance time;

address and search each load group in said event memory locations;

store said advance time in the corresponding storage location in said storage means only if said sum is before the event time of the first control event in a day group corresponding to the day represented by said real-time, or, said real-time is at or after the event time of the last control event in said day group and said sum is before the event time of the next-subsequent control event in said load group, or, there is no control event in said day group and said sum is before the event time of said next-subsequent control event.

13. A controller as recited in claim 12, wherein said processing means is operative:

to address and search said day group to find a control event whose event time is at or immediately precedes said real-time;

if a control event is found whose event time is at or immediately precedes said real time, to determine if the thus-found control event is the last control event for the day represented by said real-time;

if the thus-found control event is not the last control event, to select said real-time as an active time and to select the thus-found control event as an active control event;

if the thus-found control event is the last control event, to address and search said load group to find the next-subsequent control event therein;

if a sum of said real-time and the advance time in the corresponding storage location in said storage means is at or after the event time of the next-subsequent control event, to select said sum of real-time and advance time from the corresponding storage location of said storage means as said active time and to select said next-subsequent control event as said active control event;

If said sum of real-time and the advance time in the corresponding storage location of said storage means is before the event time of said next-subsequent control event, to select said real-time as said active time and to select said last control event as said active control event;

if a control event is not found whose event time is at or immediately precedes said real-time, to address and search said day group to find a first control event therein;

if a first control event is found is said day group, to determine if said sum of real-time and the advance time from the corresponding storage location of said storage means is at or after the event time of said first control event;

if said sum is at or after the event time of said first control event, to select said sum as said active time and to select said first control event as said active control event;

if said sum is before the event time of said first control event, to address and search backward through the day groups in said load group to find a control event whose event time immediately precedes said real-time, and to select said real-time as said active time and to select said immediately preceding control event as said active control event;

if no control event is found in said day group, to address and search forward in said load group to find the next-subsequent control event therein;

if said sum of real-time and the advance time in the corresponding storage location of said storage means is at or after the event time of said next-subsequent control event, to select said sum as said active time and to select said next-subsequent control event as said active control event;

if said sum is before the event time of said next-subsequent control event, to address and search backward through the day groups in said load group to find a control event whose event time immediately precedes said real-time, and to select said real-time as said active time and to select said immediately-preceding control event as said active control event; and

,

to determine said load-on and said load-off states for said load control circuit associated with each said load by comparing said active time with said active control event.

14. A controller as recited in claims 12 or 13, further comprising means for flagging any day of a week as a holiday;

wherein said event memory locations in said event memory means include a holiday group within each said load group; and

, wherein said processing means is operative to address and search said holiday group in each said load group when the day represented by said real-time and the day represented by said sum of real-time and the advance time in the corresponding field of said register means corresponds to the day flagged as a holiday.

15. A controller as recited in claim 12, further comprising means for de-selecting any load of a plurality of electrical loads for said advance start modification;

and, wherein said processing means is operative to store a zero in those storage locations of said storage means corresponding to the loads that have been de-selecting for said advance start modification.

16. A controller as recited in claim 2, wherein said processing means is operative to modify at least one control event associated with a load in accordance with said sensed environmental temperature.

17. A controller as recited in claim 16, wherein said sensor means is adapted to sense indoor temperature at the facility;

and, wherein said processing means is operative to implement a duty-cycle shift modification of said time schedule by increasing the predetermined portion of each control interval during which a load is on in relation to the deviation of said sensed indoor temperature from a reference temperature, but only when the load is currently being controlled in real-time in accordance with a duty-cycle control function.

18. A controller as recited in claim 17, wherein said sensor means includes a plurality of sensors respectively adapted to sense indoor temperature in a plurality of zones at the facility;

and, wherein said processing means is operative to group the plurality of electrical loads by said plurality of zones, and to implement said duty-cycle shift modification for those loads in each said zone in accordance with the corresponding sensed indoor temperature for that zone.

19. A controller as recited in claim 17, further comprising means for selecting any load of the plurality of electrical loads for said duty-cycle shift modification;

and, wherein said processing means is operative to implement said duty-cycle shift modification only for those loads that have been selected therefor.

20. A controller as recited in claim 19, wherein said means for selecting comprises a manually-actuable switch for each load;

and, wherein said processing means is operative to interrogate each said manually-actuable switch to determine those loads that have been selected for said duty-cycle shift modification.

21. A controller as recited in claim 17, wherein each said control interval is divided into a plurality of equal subintervals;

wherein each said control event stored in said event memory locations in said event memory means comprises an integral control event number representing the number of said subintervals during each control interval that a load is to be on;

wherein said processing means is operative to determine a duty-cycle shift number as a function of the deviation of said sensed indoor temperature from said reference temperature, and to implement said duty-cycle shift modification for a load by determining if the load is currently being controlled in accordance with a duty-cycle control function, and, if so, by modifying said control event number through summing of said control event number with said duty-cycle shift number, and by placing said load control circuit for each load currently being controlled in accordance with a duty-cycle control function into said load-on state for the predetermined portion of each control interval represented by said modified control event number.

22. A controller as recited in claim 21, wherein said processing means is operative to modify said control event number only if said deviation is equal to or greater than a predetermined deadband.

23. A controller as recited in claim 22, further comprising means for selectively adjusting said predetermined deadband.

24. A controller as recited in claim 21, wherein said processing means is operative to modify said control event number for a load only when the load is on.

25. A controller as recited in claim 21, further comprising means for selecting any load of the plurality of electrical loads for said duty-cycle shift modification;

and, wherein said processing means is operative to modify said control event number only for those loads that have been selected for said duty-cycle shift modification.

26. A controller as recited in claim 16, wherein said sensor means is adapted to sense indoor temperature at the facility;

and, wherein said processing means is operative to implement a night setback modification of said time schedule by determining an on state for a load whenever said sensed indoor temperature is outside predetermined primary high and low limits, by placing said load control circuit for the load in said load-on state upon occurrence of said on state, and by placing said load control circuit for the load in said load-on and said load-off states in accordance with said time schedule upon occurrence of said off state.

27. A controller as recited in claim 26, wherein said sensor means is includes a plurality of sensors respectively adapted to sense indoor temperatures in a plurality of zones at the facility;

and, wherein said processing means is operative to group the plurality of electrical loads by said plurality of zones, and to implement said night setback modification for those loads in each said zone in accordance with the corresponding sensed indoor temperature for that zone.

28. A controller as recited in claim 26, wherein said processing means is operative:

to determine said on state if said indoor temperature is outside said primary limits and if said off state has persisted for a predetermined interval; and

,

to determine said off state if said sensed indoor temperature is inside said primary limits, if said on state has persisted for a predetermined interval, and if said sensed indoor temperature is inside secondary high and low limits.

29. A controller as recited in claim 28, further comprising a minimum on timer and a minimum off timer, each said timer being controlled by said processing means to run for said predetermined interval when started by said processing means;

and,

wherein said processing means is operative to start said minimum on timer when said sensed indoor temperature is outside said primary limits and said minimum off timer is not running, and to start said minimum off timer when said sensed indoor temperature is inside said primary and said secondary limits and said minimum on timer is not running.

30. A controller as recited in claim 28, further comprising means for selecting any load of the plurality of electrical loads for said night setback modification;

and, wherein said processing means is operative to determine said on states and said off states only for those loads that have been selected for said night setback modification.

31. A controller as recited in claim 26, further comprising means for selecting any load of the plurality of electrical loads for said night setback modification;

and, wherein said processing means is operative to implement said night setback modification only for those loads that have been selected therefor.

32. A controller as recited in claim 31, wherein said means for selecting comprises a manually-actuable switch for each load;

and, wherein said processing means is operative to interrogate each said manually-actuable switch to determine those loads that have been selected for said night setback modification.

33. A controller as recited in claim 2, wherein said sensor means is adapted to sense outdoor temperature and indoor temperature at the facility;

and, wherein said processing means is operative;

to implement an advance start modification of said time schedule by advancing at least one event time associated with a load in relation to the deviation of said sensed outdoor temperature from a first reference temperature;

to implement a duty-cycle shift modification of said time schedule by increasing the predetermined portion of each control interval during which a load is on in relation to the deviation of said sensed indoor temperature from a second reference temperature, but only if the load is currently being controlled in real-time in accordance with a duty-cycle control function; and

,

to implement a night setback modification of said time schedule by determining an on state for a load whenever said sensed indoor temperature is outside predetermined primary high and low limits, by placing said load control circuit for the load in said load-on state upon occurrence of said on state, and by placing said load control circuit for the load in said load-on and said load-off states in accordance with said time schedule upon occurrence of said off-state.

34. A controller as recited in claim 33, further comprising display means for displaying data related to the operation of said controller.

35. A controller as recited in claim 34, further comprising display selection means for enabling the display of one selected type of data of a plurality of predetermined types of data, said plurality of predetermined types of data comprising:

data related to said real-time control;

the amount by which the event time of a control event is advanced under said advance start modification;

said sensed indoor temperature; and

said sensed outdoor temperature; and

,

wherein said processing means is responsive to said display selection means to transfer the type of data selected thereby to said display means.

36. A controller as recited in claim 35, wherein said display selection means comprises a manually-actuable switch having a plurality of positions each designating one of said plurality of predetermined types of data;

and, wherein said processing means is operative to interrogate said manually-actuable switch to determine the position thereof and to transfer the type of data corresponding to the thus-determined position to said display means.

37. An apparatus that permits an electronic controller, adapted to provide real-time control of the energization states of a plurality of electrical loads in accordance with a time schedule, to also provide environmentally-adaptive modifications of the time schedule in accordance with temperature at a facility at which the loads are located, the controller including:

clock means determining real-time;

an event memory storing the time schedule in the form of one or more control events and corresponding event times for each load, each control event representing a period of time during each predetermined control interval subsequent to its corresponding event time that a load is to be on;

a program memory storing a set of program instructions for real-time control; and

, a processing means for executing the set of program instructions to effect real-time control by comparing real-time from the clock means with the time schedule in the event memory, and by accordingly determining an on state or an off state for each load, and by energizing those loads in an on state and by de-energizing those loads in an off state, said apparatus comprising;

a second program memory storing a set of program instructions for said environmentally-adaptive modifications to real-time control;

means for developing a first analog signal representing an indoor temperature at the facility and a second analog signal representing outdoor temperature at the facility;

digital-to-analog signal conversion means for converting a first digital input signal into a corresponding analog signal;

a comprator for comparing either said first analog signal or said second analog signal with said analog signal from said digital-to-analog signal conversion means to provide a first digital output signal representative of the difference therebetween;

selecting means for selectively supplying either said first analog signal or said second analog signal to said comparator in response to a second digital input signal;

means for transferring said first digital input signal from said processing means to said digital-to-analog signal conversion means;

means for transferring said second digital input signal from said processing means to said selecting means;

means for transferring said first digital output signal to said processing means;

said processing means being operative to execute said set of program instructions stored in said second program memory along with the set of program instructions stored in the program memory to effect said environmentally-adaptive modifications by;

effecting analog-to-digital conversion of said indoor temperature and said outdoor temperature through the selective supplying of said first digital input signal to said digital-to-analog signal conversion means, the selective supplying of said second digital input signal to said selecting means, and the selective monitoring of said first digital output signal from said comparator;

implementing an advance start modification through advancing at least one event time for a load, in relation to the deviation of said outdoor temperature from a first reference temperature;

implementing a duty-cycle shift modification through increasing the time that a load is in said on state during each control interval in relation to the deviation of said indoor temperature from a second reference temperature; and

implementing a night setback modification through determining an on state for a load whenever said indoor temperature exceeds predetermined high and low limits thereof.

38. An apparatus as recited in claim 37, wherein said means for developing said first and said second analog signals and said selecting means include:

a first temperature sensor for sensing said indoor temperature;

a second temperature sensor for sensing said outdoor temperature;

a first calibration potentiometer;

a second calibration potentiometer; and

a first multiplexing means responsive to said second digital input signal for interconnecting said first temperature sensor and said first calibration potentiometer in a bridge circuit to develop said first analog signal, and for interconnecting said second temperature sensor and said second calibration potentiometer in a bridge circuit to develop said second analog signal.

39. An apparatus as recited in claim 37, further comprising:

a source of a third analog signal representing a selected heat advance gain;

a source of a fourth analog signal representing a selected cool advance gain; and

,

wherein said means for selectively supplying is adapted to selectively supply either said first, second, third or fourth analog signals to said comparator; and

said processing means is operative to obtain said heat advance gain and said cool advance gain by analog-to-digital conversion of said third and fourth analog signals, to vary the amount of time that an event time is advanced in relation to said cool advance gain when said outdoor temperature exceeds said first reference temperature, and in relation to said heat advance gain when said outdoor temperature is less than said first reference temperature.

40. An apparatus as recited in claim 39, wherein said processing means is operative to implement said advance start modification only if said deviation of said outdoor temperature from said first reference temperature is greater than a first deadband.

41. An apparatus as recited in claims 39 or 40, wherein said processing means is operative to implement said duty-cycle shift modification only if said deviation of said indoor temperature from said second reference is greater than a second deadband.

42. An apparatus as recited in claim 41, further comprising a deadband select switch whose position represents a selected predetermined value of said second deadband;

means coupling said deadband select switch with said processing means; and

, wherein said processing means is operative to interrogate said deadband select switch and to accordingly select a predetermined value of said second deadband in accordance with the position thereof.

43. An apparatus as recited in claim 37, further comprising a plurality of advance start select switches, each said advance start select switch having first and second positions representing, respectively, the selection and de-selection of an associated load for said advance start modification;

means coupling said plurality of advance start select switches to said processing means; and

, wherein said processing means is operative to interrogate said plurality of advance start select switches and to implement said advance start modification only for those loads whose associated advance start select switch is in said first position.

44. An apparatus as recited in claim 37, further comprising a plurality of duty-cycle shift select switches, each said duty-cycle shift select switch having said first and second positions representing, respectively, the selection and de-selection of an associated load for said duty-cycle shift modification;

means coupling said plurality of duty-cycle shift select switches to said processing means; and

, wherein said processing means is operative to interrogate said plurality of duty-cycle shift select switches and to implement said duty-cycle shift modification only for those loads whose associated duty-cycle select switch is in said first position.

45. An apparatus as recited in claim 37, further comprising a plurality of night setback select switches, each said night setback select switch having first and second positions representing, respectively, the selection and de-selection of an associated load for said night setback modification;

means coupling said plurality of night setback select switches to said processing means; and

, wherein said processing means is operative to interrogate said plurality of night setback select switches and to implement said night setback modification only for those loads whose associated night setback select switch is in said first position.

46. An apparatus as recited in claim 37, for use with a controller that further includes display means and in which said processing means is operative to store data related to real-time control, and to transfer said data related to real-time control to said display means for display thereby, said apparatus further comprising:

a display select switch having a plurality of positions representing respectively, a desired display of;

said data related to real-time control;

said indoor temperature;

said outdoor temperature; and

, the amount of time that said event times are advanced under said advance start modification;

means coupling said display select switch with said processing means; and

, wherein said processing means is operative to interrogate said display select switch and to transfer the data corresponding to the position thereof to said display means for display thereby.