Abstract: The present invention provides a motor drive system that is substantially more robust than those of the prior art. Generally, the motor drive system provides a redundant communication topology with the drives, thereby greatly reducing the chance of failure by a fault in the drive-to-drive communication link. Specifically, the motor drive system includes a plurality of motor drives joined by a communication media. Each motor drive has a motor control circuit configured to control the speed of an electric motor and a media access control unit having two communication modules. Each communications module includes a transmitter and a receiver joined to the communications media. A set of routing switches in the media access control unit joins the communication modules to connect the motor drives in an independent primary and a secondary ring communicating data for controlling the motor drives.

Abstract: An industrial control system includes a machine, a machine controller, and a safety controller. The machine controller is operable to identify a need for a human interaction, place the machine into a ready state for the human interaction, and generate a ready message responsive to placing the machine into the ready state. The safety controller is operable to receive the ready message, place the machine into a safe state responsive to receiving the ready message, and provide a human interaction indication responsive to placing the machine into the safe state.

Abstract: A safety switch that includes a body, a number of contacts, a movable plunger, a signal emitter, and a signal detector. The signal emitter and signal detector are positioned proximate the plunger and configured to assess the operability of the safety switch. The plunger is configured to selectively allow or prevent passage of a signal emitted from the signal emitter toward the signal detector depending on a position of the plunger. Control circuitry in connection with the signal detector is arranged to generate a control signal based on the detection of the emitted signal and configured to control operation of the safety switch independent of the relative position of the number of contacts.

Abstract: A power processing module for supplying power to a motion control device from a power source such as a utility power line, and related method of operation, are disclosed. The power processing module includes a first power input terminal, a first power output terminal, branch circuit protection circuitry coupled at least indirectly between the first power input terminal and the first power output terminal, and at least one bus bar coupling at least two of the first power input terminal, the first power output terminal, and the branch circuit protection circuitry.

Abstract: A method for fabricating an electrically isolated MEMS device having an outer stationary MEMS element and an inner movable MEMS element is provided that does not use a sacrificial layer. Rather, a pair of spacers are defined on the outer portions of the upper surface of a conductive wafer, and an insulating material is deposited thereon. The spacers are attached to a substrate to define an internal void therein. The wafer is then patterned to form the outer MEMS element as well as a conductive member for the inner MEMS element, separated from the outer MEMS element by a gap. A portion of the insulating layer that is disposed in the gap is then removed, thereby releasing the inner MEMS element from the stationary MEMS element.

Abstract: A method of precisely synchronizing clocks held in separate nodes on a communication network is provided that adjusts clock frequency based on a measure of relative clock rates and absolute clock offsets. In one embodiment, clock convergence is obtained with one synchronization session.