CONTROL SYSTEM

• US 20080218002A1
• Filed: 02/27/2008
• Published: 09/11/2008
• Est. Priority Date: 02/27/2007
• Status: Active Grant

• Current Assignee: Delta Systems Inc.
• Original Assignee: Delta Systems Inc.
• Inventors: STRAKA, David A.
• Granted Patent: US 8,080,905 B2
• Time in Patent Office: Days
• US Class Current: 307/131
• CPC Class Codes: F02D 2041/2048 said control involving a limitation, e.g. applying current or voltage limits
• CPC Class Codes: F02D 2041/2058 using information of the actual current value
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02D 41/28 Interface circuits
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A control system for an electrical device includes a controller that outputs an AC device enable system when one or more monitored sensors are in a proper state for operation of the electrical device. The control system may also include a sensor signal integrity checking circuit that outputs a validation signal when the sensor is one of a discrete set of acceptable sensor states. The control system may also include a current monitor that monitors the current draw of the electrical device and compares the current draw to a range of acceptable current draw levels and durations and disables operation of the electrical device when the current draw falls outside of the range.

Claims

1. A method that selectively provides power to an electrical device comprising the steps of:

monitoring at least one status sensor;

comparing a present state of the status sensor to an enable state;

when the present state of the status sensor is the enable state, generating an AC device enable signal; and

transmitting the AC device enable signal to a device control circuit that passes power to the device in response to the AC device enable signal.

2. The method of claim 1 comprising the step of conditioning the AC device enable signal prior to transmitting the AC device enable signal to the start circuit.

3. The method of claim 2 wherein the step of conditioning the AC device enable signal is performed by converting the AC device enable signal into a DC pulse train.

4. The method of claim 3 wherein the DC pulse train maintains a device bypass ground path for the operation signal in a non-conducting condition.

5. The method of claim 1 wherein the steps of monitoring the at least one status switch, comparing the present state of the status switch to the enable state, and generating the AC voltage are performed with a microprocessor.

6. The method of claim 1 comprising the steps of:

monitoring a current draw of the electrical device;

detecting a first operational mode and disabling the flow of current to the device if the current exceeds a predetermined surge current for longer than a predetermined surge time;

detecting a second operational mode and disabling the flow of current to the device if the current exceeds a predetermined run current for longer than a predetermined run time; and

disabling the flow of current if a number of times the first or second operational mode is detected exceeds a predetermined device lockout number.

7. An electrical device control system comprising:

a status sensor interface configured to receive at least one status sensor signal indicative of a present state of at least one status sensor; and

a controller configured to received the at least one status sensor signal and transmit an AC device enable signal when the present state of the at least one status sensor is an enable state.

8. The electrical device control system of claim 7 comprising a device enable rectifier that transforms the AC device enable signal into a DC pulse train.

9. The electrical device control system of claim 8 comprising a device start enabler configured to allow passage of electrical power to the electrical device in response to the AC device enable signal and wherein the device start enabler comprises a circuit that controls a ground path for electrical power to the electrical device, the ground path configured to bypass the electrical device by connecting the electrical power to ground in the absence of a pulse train from the rectifier.

10. The electrical device control system of claim 7 wherein the controller comprises:

a current monitor that monitors a current draw of the electrical device; and

an operational state detector configured to;

detect a first operational mode and disable the flow of current to the device if the current exceeds a predetermined surge current for longer than a predetermined surge time;

detect a second operational mode and disable the flow of current to the device if the current exceeds a predetermined run current for longer than a predetermined run time; and

disable the flow of current if a number of times the first or second operational mode is detected exceeds a predetermined device lockout number.

11. A method that controls operation of an electrical device based on a present state of at least two sensors, wherein each sensor is configured to exhibit one of a discrete set of acceptable sensor states indicative of an operation condition, the method comprising the steps of:

polling the sensors by;

connecting a first of the sensors to an integrity checking circuit, wherein the integrity checking circuit is configured to output a validation signal when the state of the first sensor is one of the discrete set of acceptable sensor states;

sensing the presence of the validation signal;

connecting a second of the sensors to the integrity checking circuit;

sensing the presence of the validation signal; and

enabling operation of the electrical device when the validation signal is present.

12. The method of claim 11 comprising the step of disabling the operation of the electrical device when the validation signal is not present.

13. The method of claim 11 wherein the integrity checking circuit detects a short circuit condition of the sensor having its output connected to the integrity checking circuit.

14. The method of claim 13 wherein the integrity checking circuit detects the presence of a short circuit condition caused by moisture by sinking a predetermined amount of current through the sensor that is connected to the integrity checking circuit and outputting the validation signal when the sensor passes the predetermined amount of current.

15. The method of claim 11 wherein the step of polling the sensors is performed by decoding a multiplexed input to output a sample enable signal that connects the one of the two sensors to the integrity checking circuit.

16. The method of claim 11 comprising the steps of:

monitoring a current draw of the electrical device;

detecting a first operational mode and disabling the flow of current to the device if the current exceeds a predetermined surge current for longer than a predetermined surge time;

detecting a second operational mode and disabling the flow of current to the device if the current exceeds a predetermined run current for longer than a predetermined run time; and

disabling the flow of current if a number of times the first or second operational mode is detected exceeds a predetermined device lockout number.

17. An electrical device control system comprising:

a sensor integrity circuit configured to output a validation signal;

two or more sensors, each selectively coupled to the sensor integrity circuit and configured to exhibit one of a discrete set of acceptable sensor states;

one or more sensor selector circuits, each selector circuit corresponding to one of the two or more sensors and operative to selectively connect the corresponding sensor to the sensor integrity circuit;

a polling circuit configured to activate one of the sensor selector circuits to connect the corresponding one of the sensors to the sensor integrity circuit;

wherein the sensor integrity circuit is configured to output the validation signal when the state of the sensor coupled to the sensor integrity circuit is one of the discrete set of acceptable sensor states; and

a controller configured to monitor the validation signal.

18. The electrical device control system of claim 17 wherein the polling circuit comprises a decoder that decodes a multiplexed input and outputs a sample enable signal that activates one of the sensor selector circuits.

19. The electrical device control system of claim 17 wherein the controller is configured to enable operation of the electrical device when the validation signal is present.

20. The electrical device control system of claim 17 wherein the sensor integrity circuit comprises a current sink that draws a predetermined amount of current through the selected sensor and outputs the validation signal when the selected sensor passes the predetermined amount of current.

21. The electrical device control system of claim 17 wherein the controller comprises:

a current monitor that monitors a current draw of the electrical device; and

an operational state detector configured to;

detect a first operational mode and disable the flow of current to the device if the current exceeds a predetermined surge current for longer than a predetermined surge time;

detect a second operational mode and disable the flow of current to the device if the current exceeds a predetermined run current for longer than a predetermined run time; and

disable the flow of current if a number of times the first or second operational mode is detected exceeds a predetermined device lockout number.