Environmental control system

• US 4,742,475 A
• Filed: 09/26/1984
• Issued: 05/03/1988
• Est. Priority Date: 06/19/1984
• Status: Expired due to Fees

• Current Assignee: Puritan Finance Corp.
• Original Assignee: IBG International Incorporated
• Inventors: Lapp, Theodore R., Kaiser, Frederick P.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Teska, Kevin J.
• Application Number:
  US06/655,081
• Time in Patent Office: 1,315 Days
• Field of Search: 364/131, 364/132, 364/138, 364/418, 364/493, 364/506, 364/557, 364/514, 364/550, 364/551, 364/900, 340/310 A, 340/310 CP, 340/310 R, 340/870.03, 340/870.11, 340/870.02, 165/22, 98/116, 236/49, 236/51, 318/603, 318/640
• US Class Current: 700/278
• CPC Class Codes: A01G 9/246 Air-conditioning systems
• CPC Class Codes: A01G 9/26 Electric devices A01G9/249 takes precedence
• CPC Class Codes: G05D 23/1905 associated with tele control
• CPC Class Codes: Y02A 40/25 Greenhouse technology, e.g. cooling systems therefor

Abstract

An environmental control system for use in a greenhouse or another structure which requires the control of an ambient condition regulating element in response to a plurality of sensed parameters. The system includes a plurality of sensor elements and actuator elements, which communicate with a central control through communication interface units. In an illustrated embodiment the interface units communicate over previously installed AC power lines by frequency shift keyed signals. The interface units communicate to the peripheral control elements and the central control unit through serial digital signals. The central control maintains a protocol where, in response to operator inputs, time slots are assigned to different peripheral control elements to configure the system. Each peripheral control element is thereby addressed during its time slot and a sensor responds with data corresponding to a sensed parameter and an actuator executes a command. A unique framing character is generated by the central control at the beginning of each assigned time slot for alerting the peripheral control elements an address will next be generated and for synchronizing multiple central controls to a common time slot clock.

Claims

1. A control system for varying at least one controlled paramater to control the environment of a greenhouse structure with a plurality of remotely controlled elements, said control system comprising:

a programmed controller for communicating with the plurality of remotely controlled elements over an AC power line;

said programmed controller including a stored control program defining the state of operation of each of said remotely controlled elements during a plurality of parameter stages away from a set point value for said at least one controlled parameter, said control program regulating the operation of said remotely controlled elements during each stage in said defined states to move the actual value of said controlled parameter of the greenhouse toward said set point value;

means for determining the parameter stage corresponding to the actual value of said controlled parameter of the greenhouse; and

means for commanding said remotely controlled elements to operate in accordance with said stored program for said determined stage.

2. A control system as defined in claim 1 wherein said plurality of remotely controlled elements include:

means for heating the greenhouse.

3. A control system as defined in claim 1 wherein said plurality of remotely controlled elements include:

means for cooling the greenhouse.

4. A control system as defined in claim 3 wherein said plurality of remotely controlled elements include:

means for ventilating the greenhouse with outside air; and

means for circulating the air within the greenhouse.

5. A control system as defined in claim 1 which further include:

a vent motor controller;

a remote sensor controller; and

an address controller.

6. A control system as defined in claim 5:

wherein said plurality of remotely controlled elements include a vent whose percent of opening is controlled by a motor; and

wherein said vent motor controller includes means for receiving commands from said programmed controller as to the desired percent of opening of said vent;

means for determining the present percent of opening of said vent; and

means for controlling said motor to move said vent from said present percent of opening to said commanded percent of opening.

7. A control system as defined in claim 6 wherein said vent motor controller further includes:

means for overriding said percent of opening commands in response to a manual mode signal;

means, enabled by said manual mode signal, for controlling said motor to open said vent; and

means, enabled by said manual mode signal, for controlling said motor to close said vent.

8. A control system as defined in claim 6:

wherein said vent includes means for generating pulses indicative of incremental movements of said vent,

means for generating a fully open vent signal when said vent is fully open, and

means for generating a fully closed vent signal when said vent is fully closed; and

wherein said present percent of opening determining means includes;

means for sensing said fully closed vent signal;

means for sensing said fully opened vent signal;

means for sensing said pulses;

means for generating a calibration count by counting the number of pulses between said fully opened and fully closed vent condition;

means, utilizing said calibration count, for translating said percent opening commands into a commanded number of pulses; and

said means for controlling said motor moving said vent said commanded number pulses.

9. A control as defined in claim 6 wherein said vent motor controller further includes:

means for sensing the torque on said motor; and

means for disabling said motor controlling means if the sensed torque is in excess of a threshold.

10. A control system as defined in claim 5 having at least one remote sensor:

wherein said at least one remote sensor includes a sensor for measuring an actual temperature; and

wherein said remote sensor controller includes;

means for storing an actual temperature word indicative of said actual measured temperature;

means for receiving interrogations from said programmed controller; and

means for transmitting said stored temperature word to said programmed controller in response to said interrogations.

11. A control system as defined in claim 10 wherein said temperature sensor measures outdoor temperature and said at least one remote sensor further includes:

means for measuring the occurrence of rain in excess of a predetermined amount; and

means for measuring the occurrence of wind in excess of a predetermined amount.

12. A control system as defined in claim 11 wherein:

said tranmitting means additionally transmits an indication of said measured wind and said measured rain to said programmed controller in response to said interrogations.

13. A control system as defined in claim 10 wherein said at least one sensor measures indoor temperature and said at least one remote sensor further includes:

means for measuring the indoor light level of said greenhouse.

14. A control system as defined in claim 13 wherein:

said transmitting means additionally transmits an indication of said measured light level to said programmed controller in response to said interrogations.

15. A control system as defined in claim 5 wherein said address controller includes:

means for receiving commands from said programmed controller as to the state of at least one actuator;

means for distributing actuation signals based on said received commands; and

means, controlled by said actuation signals, for controlling a plurality of actuators to determine the operational state of said remotely controlled elements.

16. A control system as defined in claim 15 wherein:

one of said remotely controlled elements is a ventilation fan.

17. A control system as defined in claim 15 wherein:

one of said remotely controlled elements is a fuel valve of a heater element.

18. A control system as defined in claim 15 wherein:

one of said remotely controlled elements is a fan motor of a heater element.

19. A control system as defined in claim 15 wherein:

one of said remotely controlled elements is a pump supplying water to a cooling pad.

20. A control system as defined in claim 5 wherein said address controller includes:

means for receiving commands from said programmed controller indicative of the position of one of said controlled elements; and

means for converting said commands into a proportional signal which positions said controlled element to the commanded position.

21. The control system as in claim 1 further including means for communicating on sidebands about a center frequency over said AC power line, comprising:

transmitter means for convering a digital binary signal having two binary levels into an upper sideband signal in response to one of said binary levels, and a lower sideband signal in response to the other binary level,

means for coupling said sideband signals to said AC power line; and

receiver means, coupled to receive said sideband signals from said AC power line, for converting said upper and lower sideband signals to respective binary logic level digital output signals.