for the life of the instrument or project. Data contained within the data sheet can provide useful information for a maintenance database.
5.0 CONSTRUCTION SPECIFICATIONS INSTITUTE
5.1 Performance-Based Specifications
Performance specifications can be used when the specifier allows the bidder to use greater flexibility in proposing equipment or methods to meet project requirements. Performance specifications are advantageous when technology changes.
5.2 Descriptive Specifications
Descriptive specifications can be used by the specifier when bidder requirements are restricted with respect to equipment or methods for technical content or project requirements.
6.0 OWNER-DEVELOPED SPECIFICATIONS
Project specifications must be reviewed and understood by the specifier before being issued for a project. To improve standardization on a site or through an organization, specifications can be developed by the organization that identifies equipment standards. Both technical and administrative specifications prepared independent of the project and offered for the project should be reviewed and edited to confirm that they are coordinated within the project manual. Another method for an organization to establish equipment standards without the constraints of a specification is to issue expected standards of automation, sometimes referred to as automation standards. Automation standards do not need to follow an established format and the content most likely will affect multiple specification sections. When an automation standard is issued, it is reasonable to expect that those standards will be incorporated to project specifications in the appropriate section. Incorporation of automation standards by reference is not prudent because conflicting requirements may be issued. Regardless, the specifier must verify that conflicting specifications are not issued.
7.0 COORDINATION WITH OTHER DISCIPLINES
Coordination of specifications for process control systems with project specifications for other disciplines, including process equipment, is essential. For example, implementation of system-wide uniformity in requirements for packaged systems (pumps, screens, centrifuges, and drives) requires either specific reference to instrumentation requirements or repeating them in equipment specifications. To reduce the risk of errors when specifying devices in more than one location, it is strongly recommended that requirements be written in one place only. As such, the reader is encouraged to include text within the other discipline section to meet the requirements of instrumentation specification. While simplifying paperwork for the contractor, listing requirements for devices and control panel details in the equipment specification requires careful replication to ensure device matching.
8.0 REFERENCES
Construction Specifications Institute (2005) The Project Resource Manual; CSI Manual of Practice, 5th ed.; Construction Specifications Institute: Alexandria, Virginia.
Instrumentation, Systems, and Automation Society (1991) Instrument Loop Diagrams; Standard ANSI/ISA-S5.4; International Society of Automation: Research Triangle Park, North Carolina.
Instrumentation, Systems, and Automation Society (1981) Specification Forms for Process Measurement and Control Instruments, Primary Elements, and Control Valves; Standard ISA-S20; International Society of Automation: Research Triangle Park, North Carolina.
9.0 SUGGESTED READINGS
American Water Works Association; American Society of Civil Engineers (1990) Water Treatment Plant Design, 3rd ed.; McGraw-Hill: New York.
American Water Works Association (2001) Instrumentation and Control; Manual of Water Supply Practices—M2; American Water Works Association: Denver, Colorado.
Construction Specifications Institute (2012) MasterFormat™; Construction Specifications Institute: Alexandria, Virginia.
Liptak, B.; Venczel, K. (1985) Instrument Engineers’ Handbook, Revised ed.; Chilton Book Co.: Radnor, Pennsylvania.
National Institute of Building Sciences (2012) The Whole Building Design Guide; http://www.wbdg.org./ (accessed May 2012).
Water Environment Federation (1993) Design of Wastewater and Stormwater Pumping Stations, 2nd ed.; Manual of Practice No. FD-4; Water Environment Federation: Alexandria, Virginia.
Whitt, M. D. (2004) Successful Instrumentation and Control Systems Design; International Society of Automation: Research Triangle Park, North Carolina.
Chapter 7
Process Control Strategies
Jack Geisenhoff, P.E., PMP
Mike Abbott, P.E.
Jeff Coulson, P. Eng, PMP
Richard S. Haugh, P.E.
Robert D. Hill, Ph.D, P.E.
1.0 OBJECTIVE OF AUTOMATIC PROCESS CONTROL
4.1 On–Off Control Versus Modulating Control
4.2 Open-Loop Versus Closed-Loop Control
4.3 Feed-Forward Versus Feedback Control
4.5 Proportional–Integral–Derivative Control
4.9 Artificial Neural Networks
4.9.1 Artificial Neural Network Models
