Thursday 2 June 2011

Systems documentation

An important facet, sometimes perhaps underestimated, in process and plant design is the documentation associated with the instrumentation and control side of the planning process. A study in this area is always welcome.

The second edition of of ISA's Instrumentation and Control Systems Documentation, by Fred A. Meier and Clifford A. Meier, incorporates improvements suggested by readers and those that reflect subsequent changes in industry practice. According to the authors, control system groups are unique in that they must coordinate with all the other work groups in a plant, mill, or factory during design, construction, commissioning, and operation. This edition explains their varied, all-encompassing language.

This easy-to-read book also provides the knowledge needed to understand and develop the documents and symbols that define a modern industrial measurement and control system. It uses industry standards, especially ANSI/ISA-5.1-2009 - Instrumentation Symbols and Identification, to define and describe the symbol-based “language” that identifies measurement and control devices.

The control systems documentation addressed within the book includes process flow diagrams, piping and instrumentation diagrams, instrument indexes and data bases, specification forms, logic diagrams, loop diagrams, installation details and location plans. The purpose and content of these documents, as well as options with regard to the information presented, are discussed in detail. Information is presented in the timeline of a typical design and engineering project. The sequence serves to show how the documents evolve and how they are interrelated. The real-world obligation of control systems documentation to support interdisciplinary coordination during design, to provide sufficient detail to bid and purchase components and services and to support all construction work is addressed. The critical requirement that these drawings and data present critical information for on-going maintenance work is integral to this presentation.

1 comment:

  1. It certainly is true that instrumentation and controls systems touch many areas of plant operation. So documentation is indeed vital, and needs to go well beyond just the "as finally working" drawings. The documentation must also include a description of how the system functions, and how it is calibrated. Besides that, the BOM and component sourcing information needs to be provided, as well as programming, program changing, and standard maintenance procedures all need to be included.