Patent Publication Number: US-7902759-B2

Title: Method of programming a lighting preset from a radio-frequency remote control

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending, commonly-assigned U.S. patent application Ser. No. 11/713,854, filed Mar. 5, 2007, entitled METHOD OF PROGRAMMING A LIGHTING PRESET FROM A RADIO-FREQUENCY REMOTE CONTROL, the entire disclosure of which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a wireless lighting control system for controlling the amount of power delivered to an electrical load from a source of alternating-current (AC) power, and more particularly, to a method of programming a lighting preset from a radio-frequency (RF) remote control. 
     2. Description of the Related Art 
     Control systems for controlling electrical loads, such as lights, motorized window treatments, and fans, are known. Such control systems often use radio-frequency (RF) transmission to provide wireless communication between the control devices of the system. One example of an RF lighting control system is disclosed in commonly-assigned U.S. Pat. No. 5,905,442, issued on May 18, 1999, entitled METHOD AND APPARATUS FOR CONTROLLING AND DETERMINING THE STATUS OF ELECTRICAL DEVICES FROM REMOTE LOCATIONS, the entire disclosure of which is hereby incorporated by reference. 
     The RF lighting control system of the &#39;442 patent includes wall-mounted load control devices, table-top and wall-mounted master controls, and signal repeaters. The control devices of the RF lighting control system include RF antennas adapted to transmit and receive the RF signals that provide for communication between the control devices of the lighting control system. All of the control devices transmit and receive the RF signals on the same frequency. Each of the load control devices includes a user interface and an integral dimmer circuit for controlling the intensity of an attached lighting load. The user interface has a pushbutton actuator for providing on/off control of the attached lighting load and a raise/lower actuator for adjusting the intensity of the attached lighting load. The load control devices may be programmed with a preset lighting intensity that may be recalled later in response to an actuation of a button of the user interface or a received RF signal. 
     The table-top and wall-mounted master controls each have a plurality of buttons and are operable to transmit RF signals to the load control devices to control the intensities of the lighting loads. The signal repeaters initiate configuration procedures for the RF lighting control system and help to ensure error-free communication by repeating the RF signals to ensure that every device of the system reliably receives the RF signals. To prevent interference with other nearby RF lighting control systems located in close proximity, the RF lighting control system of the &#39;442 patent preferably uses a house code (i.e., a house address), which each of the control devices stores in memory. Each of the control devices of the lighting control system is also assigned a unique device address (typically one byte in length) for use during normal system operation to avoid collisions between transmitted RF communication signals. 
     It is desirable to set the value of the preset lighting intensity of one of the load control devices from a remote control (e.g., from the table-top master control). Prior art wireless lighting control systems have included methods of programming the preset intensity of a load control device from an infrared (IR) remote control. To program a new lighting preset, a user adjusts the intensity of the lighting load to a desired level and then presses and holds a button on the IR remote control for a predetermined amount of time. The IR remote transmits a plurality of IR signals to the load control device while the button is held. The load control device determines that the button of the IR remote control is being held and stores the preset intensity of the lighting load as the new preset intensity. Preferably, the load control device receives a predetermined number of IR signals, e.g., ten IR signals, before determining that the button is being held. FCC limitations on average intentional power transmitted. 
     The Federal Communications Commission (FCC) regulates telecommunications and the use of the radio spectrum, including radio-frequency communications, in the United States. The rules of the FCC are provided in Title 47 of the Code of Federal Regulations. Specifically, Part 15 is directed towards radio-frequency devices. For control systems, such as RF lighting control systems, continuous transmissions are not allowed. However, periodic transmissions are acceptable as long as the FCC limitations on the average intentional power transmitted are observed. As a consequence of complying with the FCC regulations, RF lighting control systems can only transmit a limited number of RF signals in a given time period. 
     Because of the limitations on how often a control device of an RF lighting control system can transmit RF signals, an RF control device receiving an RF signal must respond rather quickly to the received RF signal, for example, after receiving only one or two RF signals. Therefore, when a button is held on an RF remote control, an RF load control device receiving an RF signal from the remote control cannot wait for ten RF signals (i.e., to determine that the button is being held) before responding to the RF signal. When a button is pressed and held on an RF remote control to program a new preset intensity, the load control device must control the lighting load immediately in response to the RF signal. Then the load control device can subsequently determine that the button is being held and store a new preset intensity. This sequence of events can be confusing to a user. 
     Therefore, there is a need for an improved method of programming a lighting preset of a load control device from an RF remote control. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method of programming a preset intensity of a load control device. The load control device is operable to control the amount of power delivered to a lighting load from an AC power source such that the lighting load is illuminated to the preset intensity. The method comprises the steps of: (1) controlling the intensity of the lighting load to an initial preset intensity in response to receiving a wireless transmission; (2) providing a visual indication representative of a new intensity in response to receiving a first predetermined number of the wireless transmissions with no more than a first predetermined time period between two consecutive wireless transmissions; and (3) storing the new intensity as the preset intensity in response to receiving a second predetermined number of the wireless transmissions with no more than a second predetermined time period between two consecutive wireless transmissions. 
     According to another embodiment of the present invention, a method of programming a preset intensity of a load control device comprises the steps of: (1) controlling the intensity of a lighting load to an initial preset intensity in response to receiving a wireless transmission; (2) providing a visual indication representative of a new intensity in response to receiving a first predetermined number of the wireless transmissions within a first amount of time; and (3) storing the first intensity as the preset intensity in response to receiving a second predetermined number of the wireless transmissions within a second amount of time. 
     The present invention further provides a dimmer switch for controlling the amount of power delivered to a lighting load from an AC power source such that the lighting load is illuminated to a preset intensity. The dimmer switch comprises a controllably conductive device, a controller, a wireless receiver, and a plurality of visual indicators. The controllably conductive device is adapted to be coupled in series electrical connection between the AC power source and the lighting load, the controllably conductive device having a control input. The controller is operatively coupled to the control input of the controllably conductive device for controlling the intensity of the lighting load. The wireless receiver is operable to receive a wireless transmission and is coupled to the controller such that the controller is responsive to the wireless transmission. The visual indicators are coupled to the controller and are operable to provide a representation of the intensity of the lighting load. The controller is operable to control the intensity of the lighting load to a new intensity. The controller is further operable to control the intensity of the lighting load to an initial preset intensity in response to receiving the wireless transmission, to blink one of the plurality of visual indicators representative of the new intensity in response to receiving a first predetermined number of the wireless transmissions with no more than a first predetermined time period between two consecutive wireless transmissions, and to store the new intensity as the preset intensity in response to receiving a second predetermined number of the wireless transmissions with no more than a second predetermined time period between two consecutive wireless transmissions. 
     In addition, the present invention provides a lighting control system for controlling the amount of power delivered to a lighting load from an AC power source such that the lighting load is illuminated to a preset intensity. The lighting control system comprises a remote control operable to transmit a wireless transmission in response to an actuation of a button. The lighting control system further comprises a dimmer switch operable to control intensity of the lighting load to a new intensity. The dimmer switch is further operable to control the lighting load to an initial preset intensity in response to receiving the wireless transmission, to provide a visual indication representative of the new intensity in response to receiving a first predetermined number of the wireless transmissions with no more than a first predetermined time period between two consecutive wireless transmissions, and to store the new intensity as the preset intensity in response to receiving a second predetermined number of the wireless transmissions with no more than a second predetermined time period between two consecutive wireless transmissions. 
     Other features and advantages of the present invention will become apparent from the following description of the invention that refers to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simple diagram of an RF lighting control system according to the present invention; 
         FIG. 2A  is a simplified block diagram of the dimmer switch of the RF lighting control system of  FIG. 1 ; 
         FIG. 2B  is a simplified block diagram of the remote control of the RF lighting control system of  FIG. 1 ; 
         FIG. 2C  is an example timeline showing the key events of the method of the present invention; 
         FIG. 3  is a flowchart of a button procedure executed by the controller of the remote control of  FIG. 2B ; 
         FIG. 4  is a flowchart of a packet receiving procedure executed by the controller of the dimmer switch of  FIG. 2A ; 
         FIG. 5  is a flowchart of a preset routine of the packet receiving procedure of  FIG. 4 ; and 
         FIG. 6  is flowchart of a preset packet timeout procedure executed by the controller of the dimmer switch of  FIG. 2A . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there is shown in the drawings an embodiment that is presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed. 
       FIG. 1  is a simple diagram of an RF lighting control system  100  according to the present invention. The lighting control system  100  comprises a remotely-controllable load control device, i.e., a dimmer switch  110 , and a remote control  120 . Preferably, the dimmer switch  110  is adapted to be wall-mounted in a standard electrical wallbox. The dimmer switch  110  is operable to be coupled in series electrical connection between an AC power source  102  and an electrical lighting load  104  for controlling the amount of power delivered to the lighting load. The dimmer switch  110  comprises a faceplate  112  and a bezel  113  received in an opening of the faceplate. 
     The dimmer switch  110  further comprises a toggle actuator  114 , i.e., a button, and an intensity adjustment actuator  116 . Actuations of the toggle actuator  114  toggle, i.e., alternately turn off and on, the lighting load  104 . Preferably, the dimmer switch  110  may be programmed with a lighting preset intensity (i.e., a “favorite” intensity level), such that the dimmer switch is operable to control the intensity of the lighting load  104  to the preset intensity when the lighting load is turned on by an actuation of the toggle actuator  114 . Actuations of an upper portion  116 A or a lower portion  116 B of the intensity adjustment actuator  116  respectively increase or decrease the amount of power delivered to the lighting load  104  and thus increase or decrease the intensity of the lighting load  104 . 
     A plurality of visual indicators  118 , e.g., light-emitting diodes (LEDs), are arranged in a linear array on the left side of the bezel  113 . The visual indicators  118  are illuminated to provide feedback of the present intensity of the lighting load  104 . Preferably, one of the plurality of visual indicators  118  that is representative of the present light intensity of the lighting load  104  is illuminated constantly. An example of a dimmer switch having a toggle actuator  114  and an intensity adjustment actuator  116  is described in greater detail in U.S. Pat. No. 5,248,919, issued Sep. 29, 1993, entitled LIGHTING CONTROL DEVICE, the entire disclosure of which is hereby incorporated by reference. 
     The remote control  120  comprises a plurality of actuators: an on button  122 , a preset button  124 , and an off button  126 . The remote control  120  may also include raise and lower buttons (not shown), which operate to respectively raise and lower the intensity of the lighting load  104 . The remote control  120  transmits packets (i.e., messages) via RF signals  106  (i.e., wireless transmissions) to the dimmer switch  110  in response to actuations of the on button  122 , the preset button  124 , and the off button  126 . Preferably, a packet transmitted by the remote control  120  includes a preamble, a serial number associated with the remote control, and a command (e.g., on, off, or preset), and comprises  72  bits. If the RF signals are transmitted at 390 MHz, a packet is approximately 23 msec in length. In order to meet the standards set by the FCC, packets are transmitted such that there is not less than a predetermined time period T MIN  (e.g., 100 msec) between two consecutive packets. 
     During a setup procedure of the RF lighting control system  100 , the dimmer switch  110  is associated with one or more remote controls  120 . The dimmer switch  110  is then responsive to packets containing the serial number of the remote control  120  to which the dimmer switch is associated. The dimmer switch  110  is operable to turn on and to turn off the lighting load  104  in response to an actuation of the on button  122  and the off button  126 , respectively. The dimmer switch  110  is operable to control the lighting load  104  to the preset intensity in response to an actuation of the preset button  124 . 
       FIG. 2A  is a simplified block diagram of the dimmer switch  110 . The dimmer switch  110  comprises a controllably conductive device  210  coupled in series electrical connection between the AC power source  102  and the lighting load  104  for control of the power delivered to the lighting load. The controllably conductive device  210  may comprise any suitable type of bidirectional switch, such as, for example, a triac, a field-effect transistor (FET) in a rectifier bridge, or two FETs in anti-series connection. The controllably conductive device  210  includes a control input coupled to a drive circuit  212 . The input to the control input will render the controllably conductive device  210  conductive or non-conductive, which in turn controls the power supplied to the lighting load  204 . 
     The drive circuit  212  provides control inputs to the controllably conductive device  210  in response to command signals from a controller  214 . The controller  214  is preferably implemented as a microcontroller, but may be any suitable processing device, such as a programmable logic device (PLD), a microprocessor, or an application specific integrated circuit (ASIC). The controller  214  receives inputs from the toggle actuator  114  and the intensity adjustment actuator  116  and controls the visual indicators  118 . The controller  214  is also coupled to a memory  216  for storage of the preset intensity of lighting load  104  and the serial number of the remote control  120  to which the dimmer switch  110  is associated. A power supply  218  generates a direct-current (DC) voltage V CC  for powering the controller  214 , the memory  216 , and other low-voltage circuitry of the dimmer switch  110 . 
     A zero-crossing detector  220  determines the zero-crossings of the input AC waveform from the AC power supply  102 . A zero-crossing is defined as the time at which the AC supply voltage transitions from positive to negative polarity, or from negative to positive polarity, at the beginning of each half-cycle. The zero-crossing information is provided as an input to controller  214  in the form of a pulse approximately every 8.3 msec (if the AC power source  102  is operating at 60 Hz). The controller  214  provides the control inputs to the drive circuit  212  to operate the controllably conductive device  210  (i.e., to provide voltage from the AC power supply  102  to the lighting load  104 ) at predetermined times relative to the zero-crossing points of the AC waveform. 
     The dimmer switch  110  further comprises an RF receiver  222  and an antenna  224  for receiving the RF signals  106  from the remote control  120 . The controller  214  is operable to control the controllably conductive device  210  in response to the packets received via the RF signals  106 . Examples of the antenna  224  for wall-mounted dimmer switches, such as the dimmer switch  110 , are described in greater detail in U.S. Pat. No. 5,982,103, issued Nov. 9, 1999, and U.S. patent application Ser. No. 10/873,033, filed Jun. 21, 2006, both entitled COMPACT RADIO FREQUENCY TRANSMITTING AND RECEIVING ANTENNA AND CONTROL DEVICE EMPLOYING SAME. The entire disclosures of both are hereby incorporated by reference. 
       FIG. 2B  is a simplified block diagram of the remote control  120 . The remote control  120  comprises a controller  230 , which is operable to receive inputs from the on button  122 , the preset button  124 , and the off button  126 . The remote control  120  further comprises a memory  232  for storage of the serial number, i.e., a unique identifier, of the remote control. Preferably, the serial number comprises a seven-byte number that is programmed into the memory  232  during manufacture of the remote control  120 . A battery  234  provides a DC voltage V BATT  for powering the controller  230 , the memory  232 , and other low-voltage circuitry of the remote control  120 . 
     The remote control  120  further includes an RF transmitter  236  coupled to the controller  230  and an antenna  238 , which may comprise, for example, a loop antenna. In response to an actuation of one of the on button  122 , the preset button  124 , and the off button  126 , the controller  230  causes the RF transmitter  236  to transmit a packet to the dimmer switch  110  via the RF signals  106 . As previously mentioned, each transmitted packet comprises a preamble, the serial number of the remote control  120 , which is stored in the memory  232 , and a command indicative as to which of the three buttons was pressed (i.e., on, off, or preset). Accordingly, a packet containing a preset command is referred to as a “preset packet”. The remote control  120  ensures that there are 100 msec between each transmitted packet in order to meet the FCC standards. 
     The lighting control system  100  provides a simple one-step configuration procedure for associating the remote control  120  with the dimmer switch  110 . A user simultaneously presses and holds the on button  122  on the remote control  120  and the toggle button  114  on the dimmer switch  110  to link the remote control  120  and the dimmer switch  110 . The user may simultaneously press and hold the off button  126  on the remote control  120  and the toggle button  114  on the dimmer switch  110  to unassociate the remote control  120  with the dimmer switch  110 . The configuration procedure for associating the remote control  120  with the dimmer switch  110  is described in greater detail in co-pending commonly-assigned U.S. Ser. No. 11/559,166, filed Nov. 13, 2006, entitled RADIO-FREQUENCY LIGHTING CONTROL SYSTEM, the entire disclosure of which is hereby incorporated by reference. 
     The lighting control system may comprise a plurality of remote controls  120  that can all be associated with one dimmer switch  110 , such that the dimmer switch is responsive to presses of the buttons  122 ,  124 ,  126  of any of the plurality of remote controls. The user simply needs to repeat the association procedure of the present invention for each of the plurality of remote controls  120 . Preferably, up to eight remote controls  120  may be associated with one dimmer switch  110 . 
     According to the present invention, the preset intensity of the dimmer switch  110  may be programmed from the remote control  120 . To program a new preset intensity of the dimmer switch  110 , a user first adjusts the intensity of the lighting load  104  to a new (i.e., desired) intensity. The user then presses and holds the preset button  124  of the remote control  120  to cause the dimmer switch to reassign the lighting preset to the new intensity.  FIG. 2C  is an example timeline showing the key events of the method of the present invention (if there is only 100 msec between each packet received by the dimmer switch  110 ). After the user first presses the preset button  124  of the remote control  120 , the dimmer switch  100  must respond immediately in order to provide an acceptable response time (since the remote control only transmits packets every 100 msec). Accordingly, the dimmer switch  124  controls the intensity of the lighting load to the initial preset intensity (i.e., the initial preset intensity) and constantly illuminates the corresponding visual indicator  118  after receiving a minimal number of packets, which preferably comprises three packets, but may be as few as one packet. 
     The dimmer switch  110  then determines if the preset button  124  of the remote control  120  is being held by counting the number of preset packets that are being received. After receiving a first predetermined number N 1  of packets (e.g., 12 packets) with no more than a first predetermined time period (e.g., 415 msec) between two consecutive packets, the dimmer switch  110  starts to blink the visual indicator  118  representative of the new intensity. After receiving a second predetermined number N 2  of packets (e.g., 80 packets) with no more than a second predetermined time period (e.g., 415 msec) between two consecutive packets, the dimmer switch  110  constantly illuminates the visual indicator  118  representative of the new intensity (rather than blinking the visual indicator), controls the lighting load  104  to the new intensity, and stores the new intensity as the preset intensity. Accordingly, the dimmer switch  110  begins the blink the visual indicator  118  representative of the new intensity after a first amount of time T 1  (e.g., approximately 1.2 seconds) while the preset button  124  is still being held, and then stores the new intensity as the preset intensity after a second amount of time T 2  (e.g., approximately 8 seconds). 
     The dimmer switch  110  is operable to revert to the initial preset intensity if the dimmer switch  110  determines that the preset button  124  is “stuck”, i.e., has been held down for a third amount of time T 3  (e.g., approximately 19 seconds). For example, an object may have fallen on the remote control  120  and is constantly actuating the preset button  124 . Specifically, if the dimmer switch  110  receives a third predetermined number N 3  of packets (e.g., 190 packets) with no more than a third predetermined time period (e.g., 415 msec) between two consecutive packets, the dimmer switch once again stores the initial preset intensity as the preset intensity. 
       FIG. 3  is a flowchart of a button procedure  300  executed by the controller  230  of the remote control  120 . The button procedure  300  is preferably executed when one of the buttons  122 ,  124 ,  126  is pressed (i.e., first depressed) at step  310 . At step  312 , the serial number of the remote control  120  is retrieved from the memory  232 , such that the serial number can be transmitted in the packet to the dimmer switch  110 . Next, a counter TX_COUNT is cleared at step  314 . The counter TX_COUNT is used by the controller  230  in order to make sure that at least a predetermined number TX MIN  of packets (e.g., four packets) are transmitted each time one of the buttoner  122 ,  124 ,  126  is pressed and released. 
     At step  316 , a timer is reset and starts increasing with respect to time. The controller  230  uses the timer to ensure that there is not less than the predetermined time period T MIN  (i.e., 100 msec) between two consecutive packets. If the on button  122  is pressed at step  318 , an on packet is transmitted, i.e., the packet is transmitted with an on command, at step  320 . Similarly, if the preset button is pressed at step  322  or the off button is pressed at step  326 , a preset packet is transmitted at step  324  or an off packet is transmitted at step  328 , respectively. 
     If the counter TX_COUNT is less than the predetermined number TX MIN  of packets at step  330 , the counter  230  increments the counter TX_COUNT and retransmits the packet at step  316 ,  320 , or  324 . When the counter TX_COUNT exceeds the predetermined number TX MIN  of packets at step  330 , the button procedure  300  then loops until the button is released at step  334  or the timer has exceeded the predetermined time period T MIN  at step  336 . When the timer exceeds the predetermined time period T MIN  at step  336  while the button is still held, the button procedure  300  loops to retransmit the packet once again at step  316 ,  320 , or  324 . If the button has been released at step  334 , the button procedure  300  exits at step  338 . 
       FIG. 4  is a flowchart of a packet receiving procedure  400 , which is also executed by the controller  214  of the dimmer switch  110 . The packet receiving procedure  400  is interrupt-driven, i.e., the procedure  400  is executed when a packet is received at step  410 . At step  412 , the controller  214  determines the serial number and command of the received packet and stores these values in respective buffers RX_SN and RX_CMD. If the serial number RX_SN contained in the received packet is not stored in the memory  232  at step  414 , the procedure  400  simply exits at step  438 . 
     In order to prevent conflict between two remote controls  120  transmitting packets to the dimmer switch  110  at the same time, the controller  214  compares the serial number of the received packet (stored in the buffer RX_SN) with the serial number of the previous received packet, which is stored in a buffer PREV_SN. If the serial number RX_SN of the received packet is stored in the memory  232  at step  414 , but the serial number RX_SN of the received packet is not equal to the serial number PREV_SN from the previous received packet at step  416 , the serial number RX_SN of the received packet is stored in the buffer PREV_SN at step  418 . Therefore, if the next packet received by the dimmer switch  100  includes the same serial number, the procedure  400  will continue on to step  420 . 
     If the serial number RX_SN of the received packet is equal to the serial number PREV_SN from the previous received packet at step  416 , a determination is made at step  420  as to whether the command RX_CMD of the received packet is equal to the command PREV_CMD form the previous received packet. If not, the command RX_CMD of the received packet is stored in the buffer PREV_CMD at step  422 . 
     If the serial number RX_SN of the received packet is stored in the memory  232  at step  416 , the serial number RX_SN of the received packet is equal to the serial number PREV_SN of the previous received packet at step  416 , and the command RX_CMD of the received packet is equal to the command PREV_CMD of the previous received packet at step  420 , a determination is made at steps  424 ,  428 , and  432  as to what type of command has been received. Therefore, the controller  214  only operates on a packet (i.e., controls the lighting load  104  in response to a received packet) after receiving the same packet three times. In summary, the controller  214  stores the serial number RX_SN of the first received packet in the buffer PREV_SN at step  418 , stores the command RX_CMD of the second received packet in the buffer PREV_CMD at step  422 , and determines what the command RX_CMD of the third received packet is at steps  418 ,  422 ,  426 . 
     If an on packet is received at step  424 , the controller  214  turns the lighting load  104  on to full intensity at step  426  and the procedure  400  exits at step  438 . If an off packet is received at step  428 , the controller  214  turns off the lighting load  104  at step  430  and the procedure  400  exits at step  438 . If a preset packet is received at step  432 , the controller  214  executes a preset routine  500  before the packet receiving procedure  400  exits at step  438 . 
       FIG. 5  is a flowchart of the preset routine  500 , which is called from the packet receiving procedure  400  and starts at step  510 . The controller  214  uses a preset packet timeout to ensure that the dimmer switch  110  does not respond to packets that are more than a maximum preset packet timeout period T TIMEOUT  (i.e., approximately 415 msec) apart. The preset packet timeout is decremented by one during a preset packet timeout procedure  600 , which is executed each half-cycle of the AC power source  102 , i.e., in response to each zero-crossing of the AC power source. The preset packet timeout procedure  600  will be described in greater detail below with reference to  FIG. 6 . Since the zero-crossings occur approximately each 8.33 msec, the preset packet timeout period is preferably reset to 50 half-cycles at step  510 , i.e., 50*8.33 msec=415 msec. 
     In order to program a new preset intensity, the user first adjusts the intensity of the lighting load  104  controlled by the dimmer switch  110  to the new intensity (i.e., the desired intensity). The user may then press and hold the preset button  124  of the remote control  120  to cause the dimmer switch  110  to save the new intensity as the preset intensity. The controller  214  of the dimmer switch  110  uses a variable PKT_COUNT to keep track of how many packets have been received, and thus, how long the preset button  124  of the remote control  120  has been held. The variable PKT_COUNT is reset to zero by the preset packet timeout procedure  600  when the preset timeout period reaches zero, i.e., when there is more than approximately 415 msec between two consecutively received packets. The variable PKT_COUNT is incremented by one at step  513  each time a consecutive preset packet is received. 
     Before pressing and holding the preset button  124  of the remote control  120 , the user adjusts the intensity of the lighting load  104  to the desired intensity. To provide an acceptable response time to an actuation of the preset button  124 , the dimmer switch  110  must control the lighting load  104  immediately after receiving the third preset packet. Accordingly, the first time a preset packet is processed by the preset procedure  500 , i.e., when the variable PKT_COUNT is equal to one at step  514 , the controller  214  saves the new intensity in the memory  232  at step  516 , controls the lighting load  104  to the initial preset intensity at step  518 , and constantly illuminates the visual indicator  118  (i.e., LED) representative of the initial preset intensity at step  520 , before the procedure  500  exits at step  550 . 
     If the preset button  124  of the remote control  120  is held for approximately the first amount of time T 1  (i.e., approximately 1.2 seconds), the dimmer switch  100  blinks the visual indicator  118  representative of the new intensity to signal that the dimmer switch is in the process of programming a new preset intensity. Specifically, after receiving the first predetermined number N 1  of packets (i.e., 12 packets) with no more than the first predetermined time period (i.e., 415 msec) between two consecutive packets (i.e., when the variable PKT_COUNT is equal to 12 at step  522 ), the controller  214  begins to blink the appropriate visual indicator  118  (i.e., LED) at step  524 . Then, the controller  214  maintains the lighting load  104  at the initial preset intensity at step  526 , continues to constantly illuminate the visual indicator  118  representative of the initial preset intensity at step  528 , and exits the procedure  500  at step  550 . 
     After the preset button  124  of the remote control  120  is held for approximately the second amount of time T 2  (i.e., approximately 8 seconds), the dimmer switch  110  saves the new intensity as the preset intensity. If the variable PKT_COUNT is equal to 80 at step  530 , i.e., the controller  214  has received the second predetermined number N 2  of packets (i.e., 80 packets) with no more than the second predetermined time period (i.e., 415 msec) between two consecutive packets, the controller  214  stops blinking the visual indicator  118  representative of the new preset intensity at step  532 . At step  534 , the controller  214  saves the initial preset intensity in memory  232 . Accordingly, the controller  214  can recall the initial preset intensity if the controller  214  determines that the preset button  124  has been held for too long (i.e., is “stuck”) as will be described below. Next, the controller  214  controls the lighting load  104  to the new intensity at step  536  and constantly illuminates the visual indicator  118  representative of the new intensity at step  538 . Then, the new intensity is stored as the preset intensity at step  540  and the procedure  500  exits at step  550 . 
     If the preset button  124  is held for more than the third amount of time T 3  (i.e., approximately 19 seconds), the controller  214  assumes that the preset button is “stuck”. If the variable PKT_COUNT is equal to 190 at step  542 , i.e., the controller  214  has received the third predetermined number N 3  of packets (i.e., 190 packets) with no more than the third predetermined time period (i.e., 415 msec) between two consecutive packets, the controller  214  controls the lighting load  104  at step  544  to the initial preset intensity, which is stored in the memory  232 . The controller  214  then stores the initial preset intensity as the preset intensity at step  546 , constantly illuminates the visual indicator  118  representative of the initial preset intensity at step  548 , and exits the procedure  500  at step  550 . 
       FIG. 6  is flowchart of the preset packet timeout procedure  600  executed by the controller  214  of the dimmer switch  110  at step  610  at each zero-crossing of the AC power source  102 , i.e., in response to the zero-crossing information provided by the zero-crossing detector  220 . The preset packet timeout is decremented by one at step  612  each half-cycle of the AC power source  102 . If the preset packet timeout not equal to zero at step  614 , the procedure  400  simply exits at step  618 . However, if the preset packet timeout has reached zero at step  614 , i.e., if more than 415 msec has passed since the last preset packet was received, the controller  124  clears the variable PKT_COUNT at step  616 . 
     Since remote control  120  transmits the preset packets approximately every 100 msec and the dimmer switch  100  does not respond to packets that are more than the maximum preset packet period T TIMEOUT  (i.e., approximately 415 msec) apart, the dimmer switch is operable to miss three consecutive preset packets without clearing the variable PKT_COUNT. However, if the dimmer switch  110  does not receive four consecutive packets (i.e., there is more than 415 msec between two consecutive packets), the variable PKT_COUNT is reset and the user must re-press the preset button  124  in order to begin the preset programming process again. 
     Since the worst case time between two consecutive packets without the variable PKT_COUNT being reset to zero is approximately 400 msec, the maximum values of the first, second, and third amounts of time T 1 , T 2 , T 3  are 4.8 seconds, 32 seconds, and 76 seconds. 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. 
     The numbers of packets, the amounts of time, and the other numerical values are provided as examples in regards to the preferred embodiment of the present invention and should not be construed to limit the scope of the present invention. For example, it would be well within the capabilities of one having ordinary skill in the art to modify the number of packets to be received for the dimmer switch to respond as described herein and still obtain the method of the present invention.