Apparatus and method for providing a multiple option select function

• US 6,119,949 A
• Filed: 01/06/1999
• Issued: 09/19/2000
• Est. Priority Date: 01/06/1999
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Lindstrom, David Eric
• Primary Examiner(s): WAYNER, WILLIAM E
• Application Number:
  US09/226,371
• Time in Patent Office: 622 Days
• Field of Search: 236/78 D, 236/20 R, 165/287, 364/528.34, 364/528.13, 324/711
• US Class Current: 236/20.00R
• CPC Class Codes: G05D 23/1902 characterised by the use of a variable reference value

Abstract

A control system and method provide a multiple option select function in which an option select resistor acts as a selector. The control system determines the resistance value of the resistor and maps the resistance value to a data entry in an option select table. The index of the data entry is determined and used to reference option parameters in at least one option parameter table. The index allows the control system to select an option parameter from many possible option parameters in the option parameter table. Furthermore, additional option parameter tables may also be referenced to select multiple option parameters using a single select resistor. The control system is disclosed as controlling a water heater system, although such control systems may be used to control other systems, such as furnaces and hydronic heating and water systems. A calibrating circuit is used to measure a transient response of an RC circuit. The resistance of the option select resistor is determined from its transient response relative to resistors in the calibration circuit.

Claims

1. Apparatus for configuring a control system that controls the environment of a medium, said apparatus comprising:

a selection circuit determining a selected operating value of a circuit element, said operating value being selectable by selecting the circuit element;

a controller circuit mapping the selected operating value to an index value in a configuration table, said index value identifying one or more configuration parameters for use by the control system, and said controller circuit providing one or more configuration parameters based on the index value; and

a supervisor circuit responsive to the controller circuit and setting the control system to a configuration specified by the configuration parameters provided by said controller circuit.

2. The apparatus of claim 1 wherein the circuit element is a resistor, the selected operating value is a resistance and said controller circuit comprises:

a mapping module mapping the resistance to a range of values;

an index determining module determining an index to the configuration table based on the range of values to which the resistance was mapped by the mapping module; and

a referencing module pulling from the configuration table one or more configuration parameters based on the index whereby said controller provides the configuration parameters to said supervisor circuit.

3. The apparatus of claim 2 wherein in the medium is a fluid and said control system is operative to control the temperature of the fluid.

4. The apparatus of claim 1 where said selection circuit comprises:

a measuring circuit measuring signal characteristics of calibration circuits interacting with a common circuit element that also interacts with said resistor;

said measuring circuit measuring signal characteristics of said resistor interacting with the common circuit element;

a computing circuit determining the resistance of said resistor based on the signal characteristics of the calibration circuits interacting with the common circuit element and based on the signal characteristics of said resistor interacting with the common circuit element.

5. A method for providing multiple options to a control system that controls the temperature of a fluid, said method comprising the operations of:

inserting a selected circuit element into the control system, said selected circuit element having an impedance indicative of control information to be applied to the control system;

determining the impedance of the selected circuit element in the control system;

mapping the impedance to an index value in a options table for the control system, said index value specifying one or more options in the options table for use by the control system; and

setting the control system to options specified by the index value.

6. The method of claim 5 wherein the circuit element is a resistor, the impedance is a resistance and said act of determining further comprises the operations of:

measuring signal characteristics of calibration circuits interacting with a common circuit element that also interacts with said resistor;

measuring signal characteristics of said resistor interacting with the common circuit element;

computing the resistance of said resistor based on the signal characteristics of the calibration circuits interacting with the common circuit element and based on the signal characteristics of said resistor interacting with the common circuit element.

7. The method of claim 6 wherein the common circuit element is a capacitor and the signal characteristics are related to the resistive and capacitive time constants of the calibration circuits interacting with the capacitor and of the resistor interacting with the capacitor.

8. The method of claim 5 wherein the selected circuit element is a resistor, the impedance is a resistance and said act of mapping further comprises the acts of:

comparing the resistance to a plurality of reference values; and

identifying a match between the resistance and a reference value if the resistance is within a predefined tolerance range of the reference value;

identifying an index value for the options table based on the reference value matched to the resistance; and

finding one or more options in the options table based on the index value.

9. The method of claim 8 wherein said act of setting comprises the operations of:

setting a maximum temperature limit on the heating.

10. A water heater control system comprising:

a selection circuit for determining an operating value of a circuit element, said operating value being selectable in accordance with said circuit element;

an option select table including at least one data entry corresponding to an index value;

an option parameter table including at least one option parameter for use in configuring the control system; and

a controller circuit for mapping said selected operating value to correspond to said at least one data entry and determining said corresponding index value, said controller circuit being configured to identify said one or more option parameters in said option parameter table based on said index value and to configure said control system as specified by said option parameters.

11. The water heater control system of claim 10 wherein said controller circuit configures said control system to control the temperature of water.

12. The water heater control system of claim 10 wherein the option select table defines valid ranges of nominal resistance into which the operating value is mapped to select the at least one option parameter.

13. The water heater control system of claim 10 wherein the option select table defines a deadband that causes the control system to reset if the operating value is mapped thereto.

14. Apparatus for configuring a control system that controls an environment of a medium, said apparatus comprising:

means for inserting a selected circuit element into the control system, said selected circuit element having an impedance indicative of control information to be applied to the control system;

means for determining the impedance of the selected circuit element in the control system;

means for mapping the impedance to an index value in a options table for the control system, said index value specifying one or more options in the options table for use by the control system; and

means for setting the control system to options specified by the index value.

15. The apparatus of claim 14 wherein the selected circuit element includes a resistor, and further comprising:

means for measuring signal characteristics of calibration circuits interacting with a common circuit element that also interacts with said resistor;

means for measuring signal characteristics of said resistor interacting with the common circuit element; and

means for determining the resistance of said resistor based on the signal characteristics of the calibration circuits interacting with the common circuit element and based on the signal characteristics of said resistor interacting with the common circuit element.

16. Apparatus for configuring a control system that controls an environment of a medium, the apparatus comprising:

a selection circuit for determining an operating value of a circuit element, the operating value being selectable in accordance with the circuit element;

an option select table including at least one data entry corresponding to an index value;

an option parameter table including at least one option parameter for use in configuring the control system; and

a controller circuit for mapping the selected operating value to correspond to the at least one data entry and determining the corresponding index value, the controller circuit being configured to identify at least one option parameter in the option parameter table based on the index value.

17. The apparatus of claim 16 wherein the controller circuit is further configured to configure the control system as specified by the identified option parameter.

18. The apparatus of claim 16 wherein in the medium is a fluid and the control system is operative to control the temperature of the fluid.

19. The apparatus of claim 16 wherein the option select table defines valid ranges of nominal resistance into which the operating value is mapped to select the at least one option parameter.

20. The apparatus of claim 16 wherein the option select table defines a deadband that causes the control system to reset if the operating value is mapped thereto.