Integration of Plant Floor Information for Scheduling and Control 961648
This paper describes the development and implementation of a real-time plant floor scheduling information support system.
Successful production scheduling and control depends largely on the availability of complete and accurate plant floor status information. In general, data must be integrated from many different and disjointed information sources. Data may come from programmable logic controllers (PLC), automatic guided vehicles (AGV), automatic storage and retrieval systems (ASRS), bar-code systems, etc. In some cases the data may be incomplete, unavailable or may lack accuracy. In order to get a clear integrated view of the entire operation, all data must be consolidated, gaps filled, and inaccuracies nullified through intelligent compensation.
The system being considered is based on the principles of dynamic modeling of asynchronously acquired shop floor events. It is based on a modified Petri Net which allows for the accurate and precise representation of plant floor logic. The system is implemented in G2 utilizing object oriented and visual programming methods and is completely interconnected in a multi-tier, socket based, client/server environment.
This system empowers the scheduler by providing on time delivery of optimally accurate, fully integrated, real-time shop floor status information, all based on asynchronous messages received from a variety of shop floor information systems. In addition, this system incorporates innovative techniques which allow for the automatic compensation of incomplete and/or inaccurate data.