delineated.
2.2.7 Detailed Process Control Narratives
The system integrator should be required to submit detailed PCNs that will ensure that his or her interpretation of the PCNs prepared by the design engineer is correct. In addition, PCNs prepared by the system integrator should include more details on how the control functions are implemented.
2.2.8 Logic Diagrams and Detailed Process Control Sequence Flow Charts
The system integrator should be required to provide logic diagrams and detailed process control sequence flow charts as part of the implementation package. When submitted early, flow charts help flush out the details of PCNs in a simple graphic format using flow chart symbols.
2.3 Sources of Technical Design Information
2.3.1 Technical Societies
Several technical societies offer a wealth of information (e.g., compact discs, conferences, online forums, periodicals, standards, textbooks, videos, workshops, etc.) on instrumentation and control system design. Of these organizations, Water Environment Federation (WEF) and the Instrumentation Testing Association (ITA) tailor their information to WRRFs, and ITA even provides test reports on instrumentation used at WRRFs. For more information on technical societies, see the “Suggested Readings” section at the end of this chapter.
2.3.2 Vendors
Because control systems must be built using commercially available products and services, vendors represent an important source of information. Design engineers should keep up to date on vendor information to ensure that their control systems make use of the best technologies available. Sources of vendor information include brochures, catalogs, compact discs, Web sites, and so on. After a preliminary review using these sources, design engineers still need to contact vendors directly for more project-specific information. Design engineers can also request a meeting with the vendor (or vendor’s representative) for a more in-depth presentation.
Water Environment Federation’s Annual Technical Exhibition and Conference, the largest water and wastewater treatment conference in North America, offers an excellent opportunity for design engineers to meet vendors and to compare products. Other important conferences include the ISA Expo and American Water Works Association’s Annual Conference and Exposition and State Water Environment Association.
2.3.2.1 Selecting Vendors and Technologies
Design engineers should thoroughly review product literature, specifications, references, and detailed manuals before selecting equipment and vendors for a wastewater treatment project. However, previous experience with particular products and their manufacturers should also influence the final decisions. As stated previously, it is also important to solicit owner input during the selection process to match existing equipment, if appropriate, or to exclude other equipment and vendors based on the owner’s experience. Phone surveys and site visits are a good way to obtain first-hand experience with unfamiliar products. Previous experience by other owners is also valuable information to solicit during the selection process.
2.3.2.2 Incorporating Selected Technologies to Design
When designing a control system for a WRRF, engineers must accommodate multiple vendor and equipment variations. Public works projects typically are awarded to the lowest bidder, who often chooses the least-expensive instruments that meet project specifications. As such, engineers must allow for such eventualities and adjust the design accordingly. For example, space must be allocated to accommodate differences in dimensions among various vendors’ equipment. Fortunately, wiring for most WRRF instrumentation has been standardized (e.g., 4- to 20-mA outputs, standard protocols [i.e., HART and Fieldbus]). Smart instruments incorporating wireless technologies and Ethernet communications should also be considered; these technologies are becoming more mainstream at industrial sites and may provide the solution to specific facility needs.
2.3.3 Books and Periodicals
“Low-tech” media such as books, journals, and magazines are great sources of technical information. Many instrumentation, control, and automation trade magazines also publish annual vendor guides. For more information, see the “Suggested Readings” section at the end of this chapter.
2.3.4 The Internet
2.3.4.1 Web Sites
The Internet is a vast pool of information that can sometimes be overwhelming. A good place to begin research is by using a general search engine (some popular search engines are listed in the “Suggested Readings” section at the end of this chapter). Useful information is also available on Web sites of industry organizations such as WEF (http://www.wef.org), ISA (http://www.isa.org), and ITA (http://www.instrument.org).
2.3.4.2 Social Media
There are numerous blogs, training videos (on YouTube and other Web sites), and tutorials dealing with automation and instrumentation specifically geared to the wastewater industry, including specialty groups in LinkedIn, Twitter, Facebook, and other social media outlets.
2.3.5 Training
Appropriate training in instrumentation and control systems can be obtained from many sources, including universities, technical societies, vendors, and experienced colleagues. For example, some technical societies now offer Internet-based training, which allows individuals to earn professional development or continuing education credits without having to travel. In addition to online presentations, this training approach allows students and the instructor(s) to interact via a phone link. In addition, vendors often offer introductions to their product line via free seminars that can be held at either the engineer’s or the vendor’s facility. Most vendors also offer some form of training on their products and services that typically is tailored to users (see Chapter 16 for more details).
2.3.6 Previous Design Experience
Many engineering firms offer a wealth of experience and can be a tremendous asset to users who may lack the time or resources to undertake the work themselves.
3.0 POSTDESIGN PHASE
3.1 Design Services During Construction
During project implementation, the design team should be involved in shop-drawing reviews, change-order preparation, and contractor and vendor meetings. In addition, the team should also respond to requests for information (RFI) and witness control system factory testing and other construction-assistance related activities during this time to ensure that the final control system will function as intended.
3.1.1 Submittals
Contractors and system integrators typically prepare detailed drawings of instrumentation systems before installing them. These drawings include loop diagrams, panel drawings, manufacturers’ data, PLC programs, DCS configuration, interconnecting wiring diagrams, and so on. The design team should thoroughly review these documents to ensure that they comply with the design’s
