PERA is a reference architecture that can model the enterprise in multiple layers and in multiple stages of the architectural life cycle. Initially PERA was part of the PERA methodology, which consisted of three main building blocks:
PERA has been further developed, and according to Gary Rathwell PERA, nowadays consists of the following components: Later in the 1990s combined insights from PERA, and other reference architectures such as GRAI Integrated Methodology, CIM-OSA, and TOVIE has led to the development of the Generic Enterprise Reference Architecture and Methodology
Purdue Reference Model, “95” provides a model for enterprise control, which end users, integrators and vendors can share in integrating applications at key layers in the enterprise:
Level 0 — The physical process — Defines the actual physical processes.
Level 1 — Intelligent devices — Sensing and manipulating the physical processes. Process *sensors, analyzers, actuators and related instrumentation.
Level 2 — Control systems — Supervising, monitoring and controlling the physical processes. Real-time controls and software; DCS, human-machine interface ; supervisory and data acquisition software.
Level 3 — Manufacturing operations systems — Managing production work flow to produce the desired products. Batch management; manufacturing execution/operations management systems ; laboratory, maintenance and plant performance management systems; data historians and related middleware. Time frame: shifts, hours, minutes, seconds.
Level 4 — Business logistics systems — Managing the business-related activities of the manufacturing operation. ERP is the primary system; establishes the basic plant production schedule, material use, shipping and inventory levels. Time frame: months, weeks, days, shifts.
David Chen, Bruno Vallespir, and Guy Doumeingts. "GRAI integrated methodology and its mapping onto generic enterprise reference architecture and methodology." Computers in industry Vol 33. p. 387-394.
Theodore J. Williams "The Purdue enterprise reference architecture." Proceedings of the JSPE/IFIP TC5/WG5. 3 Workshop on the Design of Information Infrastructure Systems for Manufacturing. North-Holland Publishing Co.
Theodore J. Williams "The Purdue enterprise reference architecture." Computers in industry Vol 24. p. 141-158.
