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An adaptive control method is proposed for applying “peak shaving” to the grid electrical demand of a single building, using a battery energy storage system to reduce the maximum demand. The objective is to save cost by reducing the monthly “demand charges” commonly levied on commercial power customers. Multiple demand forecasts are evaluated at every time step during each day, and combined to calculate...
Clock synchronization is becoming an increasingly important characteristic of modern wide area monitoring and control systems such as the power grid. It provides an opportunity to coordinate control actions and measurement instants across hundreds of miles and numerous network topologies. Devices and networks have advanced to a point where synchronization across a wide area can be achieved within...
Practical implementations in distributed model based control face a fundamental trade-off between model complexity and the number of modeled nodes. For linear systems, higher order models better capture the behavior of the system at higher frequencies, but the effective operating frequency range is limited during implementation due to sensor/actuator bandwidth limits, control algorithm limits and,...
Wide-area monitoring (WAM) applications for power distribution rely on accurate global time synchronization. Furthermore, there is interest in replacing current time synchronization methods such as Inter Range Instrumentation Group (IRIG), with distributed time synchronization protocols that utilize the data communication lines eliminating the need for dedicated timing signals within the substation...
With the increasing use of Ethernet for real-time control of distributed dynamic systems, and inexpensive processing power at the sensor and actuator nodes, there is a growing interest in the process control community to move towards “model based” distributed control. Prior work shows that the lack of precise time synchronization is a critical hindrance to reliable model generation or estimation in...
Shrinking process tolerances due to decreasing device sizes and increasing chip complexity in semiconductor manufacturing are motivating efforts to improve methods of equipment data acquisition (EDA). Prior work shows that the lack of precise time-stamping and clock synchronization is a critical hindrance to reliable data acquisition and real-time process control systems. The ultimate goal in the...
The ability to acquire quality equipment and process data is important for future real-time process control systems to maximize opportunities for semiconductor manufacturing yield enhancement and equipment efficiency. Clock synchronization for accurate time-stamping and maintaining a consistent frequency in trace data collection are essential for accurate merging of data from heterogeneous sources...
An important quality of manufacturing process implementation is ensuring that all controllers operate exactly as they are intended when applied to a system. Unfortunately, because the many subsystems in a factory are often developed independently, this is not always the case and logical errors and incorrect software-hardware interactions can exist and develop which can cause non-optimal or incorrect...
In this paper, we discuss an ECA rule based management and control system and explain what the correctness of the system means and how to verify it. We also review the previous work on the verification of inference rule bases and active rule bases which are closely related, but are not generally applicable to our case.
During its lifetime, a manufacturing system often has added functionalities or significant changes to its control system that can result in a broken control hierarchy, causing problems with debugging and reconfiguration. For the up- and-coming field of reconfigurable manufacturing systems, poor reconfigurability is especially problematic. A procedure for restructuring a standard control hierarchy...
In today's semiconductor fabrication facilities ("fabs"), coordination of time-based information throughout the factory and enterprise has become necessary to support fab-wide diagnostics, control, and information management. This has driven the need to have time synchronization at all levels of the enterprise. Time synchronization protocols such as network time protocol (NTP) and precision...
Next generation of manufacturing systems will need to be reconfigurable-capable of producing exactly the volume and type of products desired, exactly when demanded by the market- in order to accommodate the rapid changes in product design necessitated by ever-changing customer demands. The corresponding factory control systems will consist of a conglomeration of hardware and software resources that...
The improvement in Ethernet based technologies has resulted in its use in real-time applications on the factory floor. Manufacturers, vendors and end users of automation devices are aiming at the economical and technical benefits of Ethernet based communication. Many Ethernet based protocols have been developed due to the promotion by several companies and organizations. There has been a considerable...
PROFINET is the industrial Ethernet standard devised by PROFIBUS International for "Ethernet on the plant floor". PROFINET allows to implement a comprehensive communications solution on Ethernet which includes peer-to-peer communication between controllers, distributed I/O, machine safety, motion control and data acquisition. In this paper an analysis is conducted on the peer-to-peer interlocking...
The choice of implementing a safety system on a dedicated network or on a shared network (with a control system) rests solely on the system cost involved. To determine which option leads to a lower overall system cost, a two-tiered normalized weighted cost calculator approach that evaluates the trade-offs is presented. Applying the calculator to the decision process shows that either solution could...
The next generation of factory control systems will consist of a conglomeration of hardware and software resources that must work together to achieve factory-wide targets of throughput, quality and reconfigurablity. The University of Michigan's Engineering Research Center has developed a control system that extends reconfigurable software event-based control by considering a manufacturing system as...
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