Abstract: A dimmer for use in lighting control in which a triac control circuit in included which allows for control of both incandescent and low voltage lighting systems at low and high intensities 142,144. The triac control circuit includes a microcontroller 130 which alters the duration of the gate triggering pulse for the triac 134 based upon the desired intensity level of the load. This dimmer is used in a lighting control system and the dimmer is responsive to a system controller 2 as well as to momentary switch inputs which are made directly to the dimmer. The triac control circuit can also be used with other inductive loads.

Abstract: A power receptacle 10 includes a housing 12 having a cover plate 46 therefore and securable thereto, an associated pair of receptacle contacts 70 mounted within the housing 12, the contacts 70 each having pair of arms 74 having openings 78 therethrough to define a beam receiving passage 80 completely through the receptacle contacts 70, means for directing a beam of light through the beam receiving passage and including at least a light emitting component 58, and means for detecting a beam of light passing through the beam receiving passage at least including a light receiving component 60, at least one of the components 58, 60 being electrically connected ultimately to a microprocessor. Upon entry of complementary blades 84 of a plug of an electrically powered device into the receptacle contacts, the beam receiving passage 80 is blocked, thereby breaking transmission of light between the emitter 58 and receiver 60, which is ultimately detected by the microprocessor.

Abstract: A system for defining and controlling data transmissions in a multiplexing system having a host controller in bi-directional communication with a plurality of remote stations or nodes. The system comprises a series of simple frame flags generally defined as varying periods of inactivity on the bi-directional transmission line. Only specified numbers of transmitted data digits constitute valid transmissions. An arrangement is provided which responds to the receipt of an incorrect number of received digits (an error condition) in a manner which is a function of the number of digits which are actually received.

Abstract: A system for defining and controlling data transmissions in a multiplexing system having a host controller in bi-directional communication with a plurality of remote stations or nodes. The system includes a series of simple frame flags generally defined as varying periods of inactivity on the bi-directional transmission line.

Abstract: A single coil magnetic latching relay drive circuit which utilizes AC power for energizing/deenergizing the relay. To energize the relay, a single full half cycle of the AC power at a first polarity is applied to the relay coil. To deenergize the relay, a portion of a half cycle of the AC power of the other polarity is applied to the relay coil, this portion being chosen so that the effective current at the other polarity is insufficient to reenergize the relay.

Abstract: An automotive vehicle having a control switch and at least two controlled elements includes a multiplex system having a central controller, at least one control bus coupled to the controller, and remote stations which apply a multiplexed data signal to the control bus indicative of the state of the switch and which demultiplex and store control signals from the controller for controlling activation of the first and second elements. The controller is programmed to set the control signals in accordance with the switch signal and in accordance with a status signal indicative of the state of the vehicle. The status signal can indicate whether any of the doors has been opened. By using a single control switch to perform multiple functions, depending upon the state of the vehicle, the total number of switches and therefore the cost of the system is reduced.

Abstract: A data transmission system includes an oscillator which generates an ongoing sequence of clock signals, each of which defines a respective time period. Several interface circuits including first and second interface circuits are connected to the oscillator by a clock channel adapted to carry the clock signals from the oscillator to the interface circuits and a data channel adapted to carry data signals between the interface circuits. The first interface circuit places the first data signal on the data channel during the time period corresponding to a preselected one of the clock signals in each set, and the second interface circuit reads the first data signal from the data channel during this preselected time period. In this way, the first data signal is transmitted directly from the first to the second interface circuit via the data channel.

Abstract: A vehicle multiplex system includes a multiplex controller mounted in a fuse block of the vehicle. Both power buses and control buses radiate from the fuse block, and the control buses interconnect the controller with respective input and output units distributed about the vehicle. Preferably, the controller selects one of the control buses as an active bus at any given time and isolates the remaining control buses both from the active control bus and from the controller. In this way, system reliability is improved, and electromagnetic interference is reduced. By positioning the multiplex controller in the fuse block, wiring requirements for the multiplex system are simplified and the multiplex system is more readily integrated into the electrical system of the vehicle.

Abstract: A multiplex system for a vehicle includes a controller and at least two remote stations. The remote stations receive input signals indicative of commanded motor operation, and they generate output signals which command power seat motor operation. In order to store a desired seat position, the controller first commands the motors to the home position and then automatically times periods of motor operation for each of the motors as the motors are manually controlled to move the power seat to a selected position. These timed periods of motor activation are then stored as motor activation times. When it is desired to return the seat to the stored position, the controller operates automatically to move the motors to the respective home positions and then automatically to generate motor control signals to drive each of the motors for a time corresponding to the respective motor activation times.

Abstract: A vehicle multiplex system includes a controller and a number of remote stations connected to the controller by a control bus. The controller receives multiplexed signals indicative of the desired operation of loads such as headlamps and motors. In order to obtain reduced intensity headlamp operation or reduced speed of a continuous DC motor, the controller automatically connects and disconnects the headlamp or motor and a DC power source with a selected duty cycle. The period of repetition is sufficiently small to prevent perceptible flicker or fluctuation in motor speed. In this way, headlamp intensity and motor speed can be varied as desired, without increasing the hardware requirements of the system.

Abstract: A multiplex system includes a bus, a central controller coupled to the bus, and a number of remote stations coupled to the bus. The central controller applies clock signals to the bus, receives data signals from the bus, and applies data signals to the bus. The remote stations each maintain a respective count of clock signals and exchange data signals with the bus during respective time periods corresponding to respective counts. The controller operates to detect a failure of the bus and then to prevent clock signals from being carried to the remote stations associated with the failed bus. In this way, erratic operation of the remote stations is minimized.

Abstract: A motor control system includes a motor, a switch which generates a motor activation signal, a motor power source, and a multiplex system. The multiplex system includes a central controller and remote stations coupled to the switch, and to control activation of the motor. The control means controls the second remote station to activate the motor in response to the appearance of the first signal and to deactivate the motor in response to the disappearance of the first signal. The control means also automatically controls the second remote station to deactivate the motor in the event the first signal persists for a time period longer than a motor activation threshold time, thereby automatically preventing excessively long periods of motor activation.

Abstract: A multiplex system includes a master controller and a plurality of remote stations which are connected together by a cable. The cable is a twin co-ax cable which includes data and clock conductors which are surrounded by power and ground conductors. The power and ground conductors are capacitively coupled such that the power conductor simultaneously transmits power and provides an effective shield. The master controller includes a microcomputer which in turn includes an UART. The UART is used to transmit command bits to the remote stations while the CPU reads response bits from the remote stations in order to allow response bits to be interleaved in time with command bits. In one embodiment, the command bits are used to strobe row conductors of a keyboard and the response bits are used to monitor column conductors of the keyboard to allow a keyboard to be controlled by the master controller 20 in a simple and efficient manner.

Abstract: A load control system (10) generates a periodic failsafe signal (CO) and two control signals. The failsafe signal (CO) is used to drive a charge (20) pump which acts as a voltage multiplier to generate an enable signal. A DC bridge circuit (30) includes four n-channel MOSFETs (Q1-Q4), and the load control signals are used to close respective diagonally opposed pairs of the MOSFETs to apply voltage to a load. The load control signals also isolate selected switch drivers (K1-K4) from a power supply in order to prevent shorting of the bridge (30). The enable signal generated by the charge pump (20) is applied to two of the MOSFETs, and voltages are selected such that the MOSFETs will not close unless the enable signal is at a sufficiently high level to indicate proper oscillation of the failsafe signal (CO).

Abstract: This invention is an improvement of the intraplant communication system in U.S. Pat. No. 3,527,890. It comprises one base unit composed of a handset amplifier and speaker amplifier, each with its own integral power supply and each located on a common printed circuit board. This unit also features a disconnect device, formerly called a hook switch, which includes a radio frequency proximity detector which has no moving parts.