Know your control project IT scope
Understanding the scope of IT in a control system project is an important first step in identifying the expertise needed. I have been working on a project that illustrates the multitude of information technologies used in modern control systems. The project involves purpose-built equipment and control systems, packaged equipment, and control systems, HMI, MES (manufacturing execution system), d...
Understanding the scope of IT in a control system project is an important first step in identifying the expertise needed. I have been working on a project that illustrates the multitude of information technologies used in modern control systems. The project involves purpose-built equipment and control systems, packaged equipment, and control systems, HMI, MES (manufacturing execution system), data historians, and connectivity to corporate business systems. It included integration with a LIMS (laboratory information management system), a CMMS (computerized maintenance management system) and a CAPA (corrective action preventative action) management system. What made the project challenging is that the information technologies needed to make this system work are interdependent. IT elements must work together to meet control-system-project reliability, robustness, and security requirements.
One of the first parts of a system design is system partitioning, which involves mapping applications to computers and assigning computers to networks. This requires some knowledge of LANs (local area networks), VLANS (virtual LANs), network switch topologies, and network partitioning options. If wireless access devices, such as handheld HMIs, remote bar-code scanners, or wireless I/O are used, then you also need knowledge of WLAN (wireless LAN) options, including the range, throughput, interference, security, and power considerations for 802.11a, 802.11b, 802.11g, Bluetooth and other standards-based wireless options.
Network partitioning requires knowledge of security standards and best practices as well as domain management. Managing a computer domain includes managing users and privileges, user groups and privileges, computer registration and privileges, password rules, file and print sharing rules, and network services. Network services include patch and update control for the operating systems and applications, DNS (domain name services) to identify and locate computers, virus ID distribution, network monitoring (for failed applications, server health, and intrusion detection), file and printer services, and Web servers. Because the majority of control vendors use the Microsoft Windows platform, some knowledge of Microsoft Active Directory is necessary.
Application integration is next and uses a different set of IT elements. Application integration can use message queuing systems, such as IBM's WebSphere MQ and Microsoft Message Queuing Services for asynchronous message exchange, file transfer protocols (FTP) for simple file exchange, or Web services for interactive message exchange. Most new message formats are based on XML (extensible markup language) documents and use XSL (extensible stylesheet language) to map XML elements. There are also different application-specific XML specifications, such as Chemical Industry Data Exchange and B2MML (Business to Manufacturing Markup Language).
Another common way to exchange data is through databases. Databases are usually part of every project. You should be knowledgeable about database technology, such as relation database normalization rules, ERDs (entity relationship diagrams), and SQL (structured query language). Depending on the application, you may need to know something about commercial databases from Oracle, IBM, or Microsoft, or free databases.
If your system requires custom code then, in addition to knowing the implementation language, you should also be familiar with UML (universal modeling language) and development methodologies, such as RUP (rational unified process) or XP (extreme programming). Custom code development also requires the use of a configuration management system and familiarity with document management systems and backup and restore systems.
With so many different IT elements, it is impossible to be an expert in all. Fortunately, control engineers and control system developers do not have to be experts, but they do need to understand the scope of IT in their projects and be conversant with the technology.
Dennis Brandl, firstname.lastname@example.org , is the president of BR&L Consulting, a consulting firm focusing on manufacturing IT solutions, based in Cary, N.C.