Relay switch control and related methods
Exemplary embodiments are disclosed of a relay switch control configured for connection between a power source and a load. The control includes a processor having a clock upon which an operating frequency of the processor is based, and a sealed relay operable by the processor to electrically connect or disconnect the power source and the load. The relay switch control can start power to the load through the relay after a randomized time delay determined by the processor using a value of a counter of the processor. The counter is updated as a function of cycles of the clock.
1. A relay switch control comprising:
a processor configured to receive control signals from a thermostat and having an internal analog-based clock upon which an operating frequency of the processor is based, whereby the cycles of the internal analog-based clock and the operating frequency of the processor of the relay switch control are individualized to the relay switch control; and
a relay operable by the processor, in response to thermostat control signals, to electrically connect or disconnect a load to or from a voltage input received by the relay switch control from a line voltage source, where the relay switch control is configured for connection between the line voltage source and the load;
the processor of the relay switch control further configured to:
detect a line voltage signal indicating startup of line power to the load;
detect a zero crossing of a signal of the line voltage source;
upon detection of the zero crossing of the signal of the line voltage source, store at least a portion of a current value of a counter of the processor, wherein the counter is configured to update based on the cycles of the internal analog-based clock, whereby the stored value of the counter is based on a time of detection of the zero crossing of the signal of the line voltage source and individualized to the relay switch control; and
combine the portion of the stored value of the counter with a value of a cycle period length of the line voltage signal to obtain a randomized number for use as a time delay before startup of the load, whereby the time delay is random and individualized to the relay switch control based on line voltage signal and relay switch control determinants;
the relay switch control configured to start power to the load from the line voltage source through the relay after the time delay.
2. The relay switch control of claim 1 , wherein the relay is substantially enclosed in a seal.
3. The relay switch control of claim 1 , wherein:
the load includes a compressor motor; and
the relay switch control further comprises a lockout selection device in communication with the processor and selectively operable by a user to enable or disable an operational lockout of the compressor after a predetermined number of failed attempts to start the compressor.
4. The relay switch control of claim 1 , further comprising a multicolor light emitting diode (LED) operable by the processor to indicate one or more of the following: a number of cycles through which the relay has cycled, and a fault or status condition detected by the processor.
5. The relay switch control of claim 1 configured for connection between the line voltage source and a compressor in a climate control system, the control comprising a lockout selection device in communication with the processor and selectively operable by a user to enable or disable an operational lockout of the compressor after a predetermined number of failed attempts to start the compressor.
6. The relay switch control of claim 5 , wherein the lockout selection device comprises one or more of the following: a dipswitch, a rotary switch, and a jumper.
7. The relay switch control of claim 5 , wherein the lockout selection device is selectively operable to prevent an operational lockout of the compressor.
8. A relay switch control comprising:
a processor configured to receive control signals from a thermostat; and
a relay operable by the processor, in response to thermostat control signals, to electrically connect or disconnect a load to or from a voltage input provided to the relay switch control from a line voltage source, the relay substantially enclosed in a seal;
the relay switch control configured for connection as a unit between the line voltage source and the load, wherein,
the processor comprises an analog-based clock upon which an operating frequency of the processor is based; and
the processor is further configured to:
detect a line voltage signal indicating startup of line power to the load;
detect a zero crossing of a signal of the line voltage source;
upon detection of the zero crossing of the signal of the line voltage source, store at least a portion of a current value of a counter of the processor, wherein the counter is configured to update based on the cycles of the internal analog-based clock; and
combine the portion of the stored value of the counter with a value of a cycle period length of the line voltage signal to obtain a randomized number for use as a time delay before startup of the load; and
start power to the load from the line voltage source through the relay after the time delay having a length randomized by the processor using a value of a counter of the processor.
9. The relay switch control of claim 8 , wherein:
the load includes a compressor motor; and
the control further comprises a lockout selection device connected with the processor and selectively operable by a user to enable or disable an operational lockout of the compressor after a predetermined number of failed attempts to start the compressor.
10. The relay switch control of claim 9 , wherein the lockout selection device comprises one or more of the following: a dipswitch, a rotary switch, and a jumper.
11. The relay switch control of claim 9 , wherein the lockout selection device is selectively operable to prevent an operational lockout of the compressor.
12. The relay switch control of claim 8 , further comprising an indicator light and at least one pushbutton operable to provide input to the processor, the processor configured to selectively activate the indicator light based on the input.
13. The relay switch control of claim 12 , wherein the indicator light comprises a multicolor light emitting diode (LED) operable by the processor to indicate one or more of the following: a number of cycles through which the relay has cycled, and a fault or status condition detected by the processor.
14. The relay switch control of claim 8 , wherein:
the load includes a motor; and
the processor is configured to start the motor through the relay after the time delay.
15. A method of providing a random start capability for a line powered apparatus, the method comprising:
detecting a line voltage signal indicating startup of line power to the apparatus, the detecting performed by a processor of a relay switch control that receives voltage input from a line voltage source for providing the line voltage signal to the apparatus in accordance with control signals from a thermostat to the relay switch control;
upon detecting a zero cross of the line voltage signal, the processor storing at least a portion of a current value of a counter of the processor where the counter is updated based on cycles of an internal clock of the processor; and
the processor combining the portion of the stored value with a value of a cycle period length of the line voltage signal to obtain a randomized number for use as a time delay before startup of the apparatus, where the randomized number provides a time delay of between zero to about five seconds,
wherein the combining comprises multiplying the portion of the stored value with the value of the cycle period length of the signal,
the relay switch control configured to start power to the load from the line voltage source through the relay after the time delay.
16. The method of claim 15 , wherein:
the stored value is stored as a number of bits; and
the at least a portion of the stored value comprises at least some of the bits.
17. The method of claim 15 , performed by a plurality of processors for a plurality of apparatus.
18. The method of claim 15 , performed once as to the apparatus, the method further comprising using the same time delay for a plurality of subsequent startups of the apparatus.
19. The method of claim 15 , performed at more than one startup of the apparatus.
20. The method of claim 15 , wherein the apparatus includes a motor of a compressor.
21. The method of claim 20 , wherein the relay switch control is connected with the compressor.
22. The method of claim 15 , wherein the time delay provided by the randomized number is between zero and 5.1 seconds.
23. The method of claim 15 , wherein the time delay provided by the randomized number is between zero and 4.25 seconds.