Abstract: A Line Card Manager (LCM) and Node Manager architecture for use at an optical switch in an optical communications network. LCMs are provided for managing different line cards at the switch, and a Node Manager at the switch manages the LCMs. The Node Manager and LCMs exchange messages using a message-passing interface. The messages may include, e.g., read messages that enable the node manager to retrieve monitored parameter values that the LCM receives from its line card, write messages that enable the node manager to write provisioning data to the LCM, alarm messages that allow the LCMs to report alarm conditions to the node manager, an audit message that enables the node manager to verify a presence of the line card at the optical switch, and discovery messages that allow a LCM to announce its presence to the node manager, e.g., after rebooting.

Abstract: A Line Card Manager (LCM) architecture for use at an optical switch in an optical communications network. A LCM with a dedicated processor is provided for different line cards at the switch. The LCM includes a first interface, such as a connector to the line card, for receiving monitored parameters from the line card, and a processor that executes software for determining when an event such as a fault should be set, e.g., when a monitored parameter is out of range. The LCM has a second interface to a local area network at the switch for reporting the event to a Node Manager, which manages the LCM. The LCM is preferably a removable plug-in module of the line card to allow easy upgrades and maintenance. The LCM includes generic software for managing different types of line cards.

Abstract: In a steam turbine control system three overspeed protection circuits (OPC) are provided, each one being identical to the others and each having a programmable digital computer in two-way data communication with a master controller, as well as with the other OPCs. Speed transducers adjacent the turbine shaft provide speed indicative signals to the respective OPCs which calculate extremely precise RPM values utilizing an adaptive filter in the derivation process.

Abstract: A sine wave generator which utilizes a PROM for storing a predetermined bit pattern which is converted to a corresponding pulse waveform generated in response to a very accurate and stable clock pulse. The pulse waveform is shifted to a very exacting voltage level and is filtered by a band-pass filter to derive the desired fundamental frequency sine wave. The amplitude and frequency stable sine wave may be utilized in linear variable differential transformer (LVDT) apparatus for measuring the position of a controlled object such as a turbine valve. The arrangement may also be utilized for generating additional sine waves bearing some predetermined phase relationship with respect to one another for other control or signal processing applications.

Abstract: A steam turbine control system which includes a manual panel with pushbuttons for operator control of the steam admission valves. Each valve has its own control means and is responsive to pushbutton activation to govern its valve movement. If a pushbutton indicating valve opening or closing gets stuck, the operator pushes a pushbutton indicating opposite movement and the control means switches to a special control mode after a predetermined period of time. In the special mode valve movement stops after removal of the operator's finger pressure and valve movement is accomplished by activation of predetermined pairs of pushbuttons.

Abstract: Hydraulically operated turbine steam admission valves wherein each valve has its own microcomputer control. In the event the valve gets stuck due to possible contamination in the hydraulic system, the microcomputer control provides an oscillatory control signal to dither the valve. If the valve remains stuck after dithering action it is provided with a control signal of an initial magnitude greater than that normally required to close the valve.