Universal self-diagnosing appliance control

• US 4,275,464 A
• Filed: 02/16/1979
• Issued: 06/23/1981
• Est. Priority Date: 02/16/1979
• Status: Expired due to Term

• Current Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Original Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Inventors: Schmidt, David J.
• Primary Examiner(s): Malzahn, David H.
• Application Number:
  US06/012,744
• Time in Patent Office: 858 Days
• Field of Search: 235/304.1, 235/304, 364/107, 364/477, 371/15, 371/24, 371/29
• US Class Current: 714/46
• CPC Class Codes: F02B 2075/027 four
• CPC Class Codes: G05B 19/0428 Safety, monitoring G05B19/0423 takes precedence
• CPC Class Codes: G05B 2219/21144 Link between input and output, output only activated if corresponding input on
• CPC Class Codes: G05B 2219/21163 Test I-O if functional or safe value
• CPC Class Codes: G05B 2219/24069 Diagnostic
• CPC Class Codes: G05B 2219/25092 Customized control features, configuration
• CPC Class Codes: G05B 2219/25113 Strapping diodes
• CPC Class Codes: G06F 11/2236 to test CPU or processors
• CPC Class Codes: G06F 11/321 Display for diagnostics, e.g. diagnostic result display, self-test user interface
• CPC Class Codes: G06F 11/327 Alarm or error message display
• CPC Class Codes: H05B 6/6432 Aspects relating to testing or detecting leakage in a microwave heating apparatus
• CPC Class Codes: H05B 6/6482 combined with radiant heating, e.g. infrared heating
• CPC Class Codes: H05B 6/666 Safety circuits emergency protective circuits in general H02H
• CPC Class Codes: H05B 6/745 Rotatable stirrers

Abstract

A microprocessor based household appliance electronic control device is equipped with self-diagnosing cacapability and with selected option capabilities. The control includes input and output lines from an integrated circuit structure through a plug connection to external circuitry. The input/output line appearances from the microprocessor in the plug connection may be decoupled from external circuitry and cross connected to each other by means of a dummy plug. Connection to the dummy plug automatically establishes a test mode of operation for the microprocessor to cycle through a testing sequence to diagnosis internal and external failures. Error codes are provided in a visual display indicative of different types of failures. The controller is also equipped with function altering circuits which are selectively connected or bypassed with strapping diodes. Customized control features are thereby achieved in a universal electronic controller.

Claims

1. An electronic controller having a plurality of appliance function controllers, a digital display, a microprocessor controler comprising at least one internal random access memory and a plurality of internal registers, and further including, external to said microprocessor controller, electrical input and output conductors for said plurality of appliance function controllers, a diagnostic test signal conductor connected to said microprocessor controller, a single plug connector to which said input and output conductors and said diagnostic test signal conductor are connected in circuit, said plug connector and having releasable connections for each of said conductors, a corresponding mating connector releasably engageable with said single plug connector and having releasable connections that match the releasable connections of said single plug connector, said mating plug connector including extension conductors from said input and output conductors to the respective appliance function controllers associated with each input and output conductor, a dummy plug connector releasably engageable with said single plug connector in place of said mating plug connector, said dummy plug connector containing leads which cross connect said input and output conductors and which place a signal on said diagnostic test signal conductor to thereby alter the electrical interconnection of said conductors in said single plug connector, and means in said microprocessor controller interconnecting said random access memory, said internal registers, and connected to said digital display, and responsive to signals on said diagnostic test signal conductor to internally check electrical conductivity integrity of said input and output conductors and of said internal microprocessor random access memory and of said internal microprocessor registers and operative to generate a unique digital code in said digital display indicative of an unsatisfactory check of electrical integrity and the location among said input and output conductors and said microprocessor random access memory and registers at which said unsatisfactory check occurred.

2. Apparatus according to claim 1 further characterized in that said random access memory includes a plurality of discrete addressable storage locations, and said internal microprocessor controller registers include accumulator, and said microprocessor controller includes means for reproducing information from said accumulator register into at least some of said addressable storage locations of said random access memory, and said means in said microprocessor controller to check electrical conductivity integrity reproduces information from said accumulator in at least some of said addressable storage locations of said random access memory and thereafter serially compares the contents of said discrete addressable storage locations in said random access memory with the contents of said accumulator, and provides indications of any inexact comparison to said digital display.

3. Apparatus according to claim 1 further comprising data access lines connected to said microprocessor controller, an input means in said microprocessor controller connectable to said data access lines to provide predetermined data signals and further characterized in that said means in said microprocessor controller responsive to signals on said diagnostic test signal conductor generates control signals which are sent on said data access lines and returned through said input means as said data signals and further comprising means in said microprocessor controller for comparing said generated control signals with said data signals, and means responsive to said comparison to actuate said digital display when said comparison reflects inequality between said control signals and said data signals.

4. Apparatus according to claim 1 further comprising an a.c. conductor connected to an a.c. input external of said microprocessor controller and to an a.c. line signal detection means in said microprocessor controller which is pulsed to one binary bit condition by an incoming a.c. line signal on said a.c. conductor, means in said microprocessor controller for forcing said a.c. line signal detection means to the opposite bit condition, and sampling means in said microprocessor controller for testing the bit condition of said a.c. line signal detection means to provide an indication to said digital display of an unsatisfactory check upon subsequently detecting said opposite binary bit condition while sampling said a.c. line signal detection means.

5. Apparatus according to claim 1 further comprising manual input data lines to said microprocessor controller and manual input means connectable to said manual input data lines for generating distinct input signals to said microprocessor controller on said data input lines, buffer memory means in said microprocessor controller for temporarily storing said input signals as they are generated in association with each of said manual input means, recording means external to said microprocessor controller for storing a visible record of correct correspondence of said input signals and the manual input means associated therewith, and said digital display is connected to said buffer memory means for generating a visual image of said input signals for manual comparison with said corresponding record in said recording means to ascertain whether or not electrical integrity exists in the generation and display of said input signals from said manual input means.

6. Apparatus according to claim 1 further comprising a temperature probe having a thermistor connected in series to a voltage source external to said microprocessor controller and a temperature sampling circuit is coupled to a first probe input to said microprocessor controller from said temperature probe and a probe status circuit external to said microprocessor controller is coupled to a second probe input to said microprocessor controller from said temperature probe, and said microprocessor controller stores a signal in a probe status location in said random access memory to indicate the presence or absence of said probe, and said dummy plug connector leads cross connect said temperature sampling circuit to said probe status circuit and said means in said microprocessor controller responsive to signals on said diagnostic test signal conductor is coupled to receive an electrical signal from said probe status circuit to said second probe input and is coupled to said probe status location in said random access memory to compare said electrical signal on said second probe input with the contents of said probe status location in said random access memory to generate a unique digital code indicative of relative concordance thereof to said digital display.

7. Apparatus according to claim 6 wherein said means in said microprocessor controller responsive to signals on said diagnostic test signal conductor generates maximum and minimum probe test limit signals and compares signals on said first probe input with said maximum and minimum probe test limit signals to check the electrical integrity of said probe.

8. Apparatus according to claim 7 further characterized in that said means responsive to signals on said diagnostic test signal conductor actuates said digital display when the voltage of the signal received on said first probe input does not fall between said maximum and minimum probe test limit signals.

9. Apparatus according to claim 1 further characterized in that at least some of said leads in said dummy plug serve as connection altering means to disconnect first ones of said output conductors from associated function controllers external to said microprocessor controller, and to connect said first output conductors to others of said output conductors which are connected to said microprocessor controller to temporarily use said other output conductors as input lines, and said means responsive to signals on said diagnostic test signal conductor includes means for directing control signals to said first output conductors, means for sampling said other output conductors serving as input lines, and means for actuating said digital display upon failure of said control signals to appear on said input lines.

10. Apparatus according to claim 1 wherein said means responsive to signals in said diagnostic test signal conductor is connected to place a binary code in at least one of said plurality of internal registers, to replicate said binary code in at least one other internal register, and to compare the binary codes in said one and said other registers and to transmit an error code to said digital display upon detecting an inexact comparison of binary codes in said one and said other registers.

11. In an electronic controller which employs a microprocessor, data input lines connected to said microprocessor and data output lines connected from said microprocessor, the improvement comprising a matrix of a plurality of function alteration circuits coupled to said data input and output lines, said circuits including separate strapping means selectively completing each function alteration circuit for alternative connection and disconnection in said matrix to operate said microprocessor in alternative selected functional modes of operation.

12. Apparatus according to claim 11 further characterized in that said electronic controller includes a keyboard connected to said microprocessor for entering a preset temperature into said microprocessor, and said electronic controller is connected in a microwave oven having a temperature probe, and said microprocessor is conditioned by manual actuation of said keyboard to operate said microwave oven until said probe reaches a preset temperature, and one of said data output lines serves as a probe temperature control line, and connection and disconnection of one of said strapping means associated with said probe temperature control line selectively completes a function alteration circuit associated therewith to hold said probe at said present temperature and alternatively to cease heating once said probe reaches said preset temperature.

13. Apparatus according to claim 11 further comprising an illuminable display, and one of said data output lines serves as a display gating line connected between said microprocessor and said illuminable display to enable said display under the control of said microprocessor, and a power lead is connected to said microprocessor, and one said strapping means is associated with said display gating line to selectively complete a function alteration circuit associated therewith to alternatively periodically activate and deactivate said display gating line and alternatively to continually activate said display gating line upon the occurrence of an initial supply of power on said power lead.

14. Apparatus according to claim 11 further characterized in that said electronic controller is connected in a microwave oven having a probe detection switch and a probe detection input line leading from said probe detection switch to said microprocessor, and one of said data input lines serves as a probe interlock convention input line leading to said microprocessor for carrying a bit convention signal thereto, and one of said strapping means is associated with said probe interlock convention input line and selectively completes one of said function alteration circuits to establish one of two alternative bit conventions indicative of connection of a probe to said microwave oven.

15. Apparatus according to claim 11 further characterized in that electronic controller is connected in a microwave oven having a magnetron relay, a browner relay, and a cooking cycle control line associated with a final one of several sequential cooking cycles, and one of said strapping means selectively completes a function alteration circuit to said cooking cycle control line to an alternative one of said magnetron relay and said browner relay.

16. Apparatus according to claim 11 further characterized in that said electronic controller is connected in a microwave oven having a keyboard with a plurality of keys thereon, an audible horn, and a horn output line connected between said horn and said microprocessor, and one said data input lines is a line coupled to said microprocessor which serves a manual keyboard input activation signal line, and one of said strapping means selectively complete a function alteration circuit for alternative coupling and decoupling of said keyboard activation signal line to said horn output line.

17. Apparatus according to claim 11 further characterized in that said electronic controller is connected in a microwave oven having an oven door, and an oven door switch operably connected to open and close upon opening and closing of said oven door, a door interlock signal line connected between said oven door switch and said microprocessor to signal when said oven door switch is open and closed, and said matrix includes as one of said function alteration circuits an interlock connection input circuit leading to said microprocessor for supplying a bit convention signal thereto, and one of said strapping means selectively completes a function alteration circuit to establish a binary bit convention to said microprocessor indicative of the status of said oven door.

18. Apparatus according to claim 11 further characterized in that said electronic controller is connected in a microwave oven having a magnetron, and further comprising a magnetron duty cycle interval controller coupled to operate said oven magnetron in a repetitive duty cycle, and a magnetron power level control line is connected between said microporcessor and said magnetron duty cycle interval controller, and one of said strapping means selectively completes a function alteration circuit to activate said magnetron power level control line to alternatively adjust said magnetron duty cycle interval controller between a full and partial duty cycle of operation.

19. Apparatus according to claim 11 further characterized in that said electronic controller is connected in a microwave oven having a manually actuable start switch, a cooking start input circuit in said microprocessor coupled to said start switch by one of said data input lines, a cooking stop input circuit coupled to said start switch by one of said data input lines, means in said microprocessor for alternatively actuating said cooking start input circuit and said cooking stop input circuit upon actuation of said start switch, and one of said strapping means selectively completes a function alteration circuit to enable said cooking stop input circuit and alternatively to disable said cooking stop intput circuit and to force said means for alternatingly actuating said cooking start input circuit and said cooking stop input circuit to instead actuate said cooking start input circuit with every actuation of said start switch.

20. Apparatus according to claim 11 further characterized in said electronic controller is connected in a microwave oven having a temperature probe, and further comprising an analog temperature indication line leading from said probe to said microprocessor, means for generating digital numbers in said microprocessor on a Centigrade scale in response to analog input on said analog temperature indication line, means for generating digital numbers in said microprocessor on a Fahrenheit scale in response to an analog input on said analog temperature indication line, and one of said strapping means selectively completes a function alteration circuit for alternatively coupling said analog temperature indication line to said means for generating digital numbers on a Centrigrade scale and to register said numbers in said microprocessor and to said means for generating digital numbers on a Fahrenheit scale and to register said digital numbers in said microprocessor.

21. Apparatus according to claim 11 further characterized in that said electronic controller is connected in a microwave oven and further comprising a magnetron relay means, a duty cycle interval controller connected to said microprocessor and connected to activate said magnetron relay means for a prescribed duty cycle interval, recycling means in said microprocessor for periodically reactivating said duty cycle interval controller, and at least one of said strapping means selectively completes a function alteration circuit to alternatively recycle said duty cycle interval controller at one of a plurality different frequencies.

22. Apparatus according to claim 21 further characterized in that recycling means operates said duty cycle interval controller at a 15 second duty cycle.

23. Apparatus according to claim 21 further characterized in that said recycling means operates said duty cycle interval controller at a duty cycle of 30 seconds.

24. Apparatus according to claim 21 further characterized in that said recycling means operates said duty cycle interval controller at a one second duty cycle.

25. Apparatus according to claim 11 in that said electronic controller is connected in a microwave oven having a magnetron for heating said oven to a predetermined temperature, and further comprising a magnetron controller coupled to operate said magnetron, a temperature output control line connected from said microprocessor to said magnetron controller for regulating oven temperature at said predetermined temperature when said predetermined temperature is reached, minimum temperature memory means in said microprocessor for storing said predetermined temperature, disabling circuit means in said microprocessor connected between said minimum temperature memory means and said temperature output control line for deactivating said temperature output control line once oven temperature reaches and thereafter falls below said predetermined temperature, and one of said strapping means selectively completes a function alteration circuit for alternatively engaging said disabling circuit means and by-passing said disabling circuit means to connect said minimum temperature memory means to said temperature output control line.

26. Apparatus according to claim 11 further comprising a visual display connected to said microprocessor and in which images of numbers appear side-by-side, luminescent ennunciators located above and below said images of said numbers in said visual display, an upper ennuciator activation circuit connected between said microprocessor and said visual display for enabling said luminescent ennunciator above said numbers, a lower ennunciator activation circuit connected between said microprocessor and said visual display for enabling said luminescient ennuciator below said numbers, and one of said strapping means selectively completes a function alteration circuit for alternatively conditioning said microprocessor to enable said upper ennunciator activation circuit and to alternatively enable said lower ennuciator activation circuit.

27. Apparatus according to claim 11 further comprising a clock circuit and a manually operable keyboard means for designating a preselected time, and further characterized in that said microprocessor has a current time memory storage means connected to said clock circuit for storing an electronic indication of current time and a preselected time memory storage means connected to said manually operable keyboard for storing an electronic indication of a preselected time provided form said manually operated keyboard means, comparator means connected to said current time memory storage means and said preselected time memory storage means for comparing said preselected time with current time and for providing enabling signal when current time reaches said preselected time, and further characterized in that external to said microprocessor one of said data input lines serves as a delayed start control line coupled to said microprocessor for enabling said comparator means, and one of said strapping means selectively completes a function alteration circuit to establish an enabling connection from one of said keys of said manually operated keyboard to said delayed start control line input means.