Systems and methods for controlling appliances
A control system for controlling operation of an appliance includes a first signal source configured to produce an alternating current (AC) signal, a second signal source configured to produce a second signal, and a controller. The controller includes a processor, a memory device, a first input pin coupled to the first signal source to receive the AC signal, a second input pin coupled to the second signal source to receive the second signal, and an analog to digital (A/D) converter. The A/D converter is coupled to the first input pin and the memory device storing instructions that when executed by the processor cause the processor to sample the second signal at the second input pin only when the first signal has a value of about zero volts at the first input pin.
1. A control system for controlling operation of an appliance, the control system comprising:
a first signal source, the first signal source configured to produce an alternating current (AC) signal;
a second signal source, the second signal source configured to produce a second signal; and
a controller, the controller comprising:
a processor;
a memory device;
a first input pin coupled to the first signal source to receive the AC signal;
a second input pin coupled to the second signal source to receive the second signal; and
a first analog to digital (A/D) converter coupled to the first input pin, the memory device storing instructions that when executed by the processor cause the processor to sample the second signal at the second input pin only when the first signal has a value of about zero volts at the first input pin.
2. The control system of claim 1 , wherein the first signal source comprises a sensor.
3. The control system of claim 2 , wherein the sensor comprises at least one dip switch.
4. The control system of claim 1 , wherein the first signal source is configured to produce the AC signal with a voltage of about twenty-four volts.
5. The control system of claim 1 further comprising a second A/D converter coupled to the second pin.
6. The control system of claim 1 , wherein the controller is configured to be powered by a voltage at a first magnitude and the first signal source is configured to produce the AC signal with a voltage at a second magnitude greater than the first magnitude.
7. The control system of claim 6 , wherein the second magnitude is at least twice the first magnitude.
8. The control system of claim 1 further comprising a third signal source configured to produce a third signal, the controller further comprising a third input pin coupled to the third signal source to receive the third signal, the memory device storing instructions that when executed by the processor cause the processor to sample the third signal at the third input pin only when the first signal has a value of about zero volts at the first input pin.
9. The control system of claim 8 , wherein the memory device stores instructions that when executed by the processor cause the processor to sample the second signal at the second input pin a first time the first signal has a value of about zero volts at the first input pin and sample the third signal at the third input pin at a later, second time the first signal has a value of about zero volts at the first input pin.
10. The control system of claim 8 , wherein the memory device stores instructions that when executed by the processor cause the processor to sample the second signal at the second input pin and the third signal at the third input pin during a same time the first signal has a value of about zero volts at the first input pin.
11. A method of controlling operation of an appliance with a controller including a processor, a first input pin, and a second input pin, the first input pin coupled to an analog to digital (A/D) converter, the method comprising:
receiving, at the first input pin of the controller, an alternating current (AC) signal from a first signal source;
receiving, at the second input pin of the controller, a second signal from a second signal source;
determining, by the processor, when the first signal has a value of about zero volts at the first input pin; and
sampling, by the processor, the second signal at the second input pin only when the first signal has a value of about zero volts at the first input pin.
12. The method of claim 11 , wherein receiving an AC signal from a first signal source comprises receiving an AC signal from a sensor.
13. The method of claim 12 , wherein receiving an AC signal from a sensor comprises receiving an AC signal from at least one dip switch.
14. The method of claim 11 , wherein receiving an AC signal from a first signal source comprises receiving an AC signal from a first signal source configured to produce the AC signal with a voltage of about twenty-four volts.
15. The method of claim 11 , wherein receiving at the second input pin of the controller comprises receiving, at the second input pin coupled to an A/D converter.
16. The method of claim 11 , wherein receiving an AC signal from a first signal source comprises receiving an AC signal with a voltage at a second magnitude greater than a first magnitude of a voltage by which the controller is configured to be powered.
17. The method of claim 16 , wherein receiving an AC signal with a voltage at a second magnitude greater than a first magnitude comprises receiving a voltage with a second magnitude that is at least twice the first magnitude.
18. The method of claim 11 further comprising receiving, at a third input pin of the controller, a third signal from a third signal source, and sampling, by the processor, the third signal at the third input pin only when the first signal has a value of about zero volts at the first input pin.
19. The method of claim 18 , further comprising sampling, by the processor, the second signal at the second input pin a first time the first signal has a value of about zero volts at the first input pin and sampling the third signal at the third input pin at a later, second time the first signal has a value of about zero volts at the first input pin.
20. The method of claim 18 , further comprising sampling, by the processor, the second signal at the second input pin and the third signal at the third input pin during a same time the first signal has a value of about zero volts at the first input pin.
21. A control system for controlling operation of an appliance, the control system comprising:
a first signal source, the first signal source configured to produce an alternating current (AC) signal;
a second signal source, the second signal source configured to produce a second signal; and
a controller, the controller comprising:
a processor;
a memory device;
a first input pin coupled to the first signal source to receive the AC signal;
a second input pin coupled to the second signal source to receive the second signal; and
a clamp circuit coupled to the first input pin to receive the AC signal and output a square wave to the processor, the memory device storing instructions that when executed by the processor cause the processor to sample the second signal at the second input pin only when the first signal has a value of about zero volts at the first input pin.
22. The control system of claim 21 , wherein the first signal source is configured to produce the AC signal with a voltage of about twenty-four volts.
23. The control system of claim 21 further comprising an A/D converter coupled to the second pin.
24. The control system of claim 21 , wherein the controller is configured to be powered by a voltage at a first magnitude and the first signal source is configured to produce the AC signal with a voltage at a second magnitude greater than the first magnitude.
25. The control system of claim 24 , wherein the second magnitude is at least twice the first magnitude.
26. The control system of claim 21 further comprising a third signal source configured to produce a third signal, the controller further comprising a third input pin coupled to the third signal source to receive the third signal, the memory device storing instructions that when executed by the processor cause the processor to sample the third signal at the third input pin only when the first signal has a value of about zero volts at the first input pin.
27. The control system of claim 26 , wherein the memory device stores instructions that when executed by the processor cause the processor to sample the second signal at the second input pin a first time the first signal has a value of about zero volts at the first input pin and sample the third signal at the third input pin at a later, second time the first signal has a value of about zero volts at the first input pin.
28. The control system of claim 26 , wherein the memory device stores instructions that when executed by the processor cause the processor to sample the second signal at the second input pin and the third signal at the third input pin during a same time the first signal has a value of about zero volts at the first input pin.
29. The control system of claim 21 , wherein memory device stores instructions that when executed by the processor cause the processor to determine when the first signal has a value of about zero volts at the first input pin by identifying at least one edge of the square wave output by the clamp circuit.