2.5 Factory Automation equipment Description Language

Recent progress of the personal computer (PC) loads a way to use PCs not only as the man-machine interface part of the equipment, but also as the embedded controller of the equipment. But, we can hardly say that we can use a PC with conventional Operating Systems designed for OA as the controller which totally control the equipment, because the normal OS does not have the hard-realtime capability (please note that the it can be used in the soft-realtime area, which allows the lack of data stream, ex. multimedia). Therefore, it is reasonable to use a combination of a PC and Adapter Cards: a PC acts as generating the control sequence stream, and Adapter Cards act as the actual control of the equipment. From this points of view, the architecture that include the current system (PC + intelligent adapter) and the future system (high performance PC + motion control level adapter) is important. In this architecture, the data which can describe total equipment behavior from the element level (motor, PLC, ...) to the work level (make a groove, ...) becomes one of the most important issues.

The progress of software technology makes it possible to use the potential power of PCs. Especially, 2 aspects of the software technology progress; (a) Object Oriented Programming, (b) Interpreter, can change the embedded systems design. But the current data representation of CNC, which became ISO standard on 60's, is too old to become the basis of the current or future CNC architecture. Requirements for the new data representation are:

• Object Oriented Design (Common Process Objects): Object oriented data representation of the process (groove, hole, etc.) is one of the key for the future CAM (Computer Aided Manufacturing) system. When the common process object models are defined and used in CAM, CAM system can produce the CNC data directly.
• Abstraction of the hardware:
  Data itself must be portable for every machine which has the interpreter. For example, the location of tools must not be hard coded into the data like the ISO NC data.
• Curve:
  Recent progress of the 3 dimensional CAD (Computer Aided Design) makes the mechanical designers possible to design the curved shapes, but the current NC data has no standard to represent the curve and this lack makes the NC data large.
• Wide Coverage:
  Data covers wide enough to represent the equipment control from the element (motor, sequencer, ...) level to the work level (make a groove, ...).
• Representation Standard:
  Current NC data has ``custom macro'', developed differently by each vendor, but this representation is different from one to another. New data representation must be based on the common script language developed in the information systems.

We design Factory Automation equipment Description Language (hereafter, FADL) to make an answer for the data representation requirement of FA equipment, (CNC, manipulator, ...).

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