Abstract: An optical encoder assembly reduces the space required to mount multiple thumbwheels on a control panel by utilizing wheels with integral encoder patterns. An encoder pattern comprising two tracks of reflective dots is attached to the side of each wheel. Two optical transceivers are mounted on a printed circuit board next to each wheel so that the pattern elements in each of the tracks move past one of the transceivers as the wheels rotate. The transceivers send electrical pulses to a microprocessor each time a dot passes a transceiver. The dots in the two tracks are offset circumferentially to provide a 90 degree phase shift between the tracks as the wheels rotate on a common shaft. The use of dots reduces blurring of the pulse signals. A chassis is mounted to the panel and supports the shaft, the printed circuit board, and a rubber dust shield which rubs against the wheels to provide braking action. The chassis, printed circuit board and dust shield all include slots through which the wheels rotate.

Abstract: A theatrical lighting control network which incorporates a local area network for communication among a number of node controllers and control consoles or devices employed in establising lighting or other effects levels in a theater, film production stage or other performance environment. Use of the network eliminates the requirements for the majority of hardwiring for interconnection of consoles and other controller or monitoring devices to effects controller racks and provides great flexibility in location and relocation of various components of the system.

Abstract: A dimmer rack utilizes removable connector modules for interfacing the rack to various types of standard electrical connectors in pre-existing lighting systems. The dinner rack includes a front bay for receiving dimmer modules, a rear bay for receiving the connector modules, and a patch panel for routing electrical power from the dimmer modules to the connector modules. Each connector module includes a rear panel having a connector for connecting the module to the patch panel and a front panel having a standard electrical connector for connecting the module to a lighting system. The connector modules can be fabricated with various types of standard electrical connectors.

Abstract: A dimming control system includes dimmer modules which receive dimming level information from a control module. Each dimmer modules includes a microprocessor which provides internal intelligence for controlling power to a load in response to the dimming level information. The control module receives industry standard protocol dimming information from various sources, converts it to dimming level information, and communicates the dimming level information to the dimmer modules through serial communication lines. The dimmer modules and control module are mounted in a rack which includes a backplane having nonvolatile memory device that retains configuration data even if the control module is removed from the rack. The dimmer modules implement a zero cross prediction method which includes detecting an actual zero cross, calculating an error, and adding the error to the period of a line power signal.

Abstract: A high density dimmer module controls four separate lighting circuits and provides adequate cooling while maintaining a form factor identical to conventional dimmer modules. The module includes circuit breakers arranged in stacks located adjacent to the front of the module. The circuit breaker stacks are spaced apart to allow cooling air to flow between, and to each side of, the circuit breakers. The air then flows past a power device and four toroidal inductors which are arranged behind and between the stacks. In a preferred embodiment, the module includes an input power connector positioned adjacent the rear periphery of the module chassis, first and second stacks of circuit breakers positioned adjacent the front periphery, four inductors arranged in an arcuate pattern behind the circuit breaker stacks, a power device located adjacent a sidewall of the chassis, and four output load connectors positioned adjacent the rear periphery.