Eight Design Tips for Integration
October 01, 2008
Appeared in Consulting-Specifying Engineer
In the past five years, several facilities located in North America have come to realize many of the technological benefits of system integration and interoperability. System integration has proven to help facility managers meet the overarching demand to heighten efficiency as facilities watched their cost of energy rise steadily.
These “open” system networks using industry-standard network communication protocols allow control devices to be easily defined, installed, and reconfigured while sharing information in a multi-vendor environment. As facilities become more integrated, design professionals need to continue to leverage the power of system integration and interoperability. The continuous advancement of technology has fundamentally changed “how” we design and operate these facilities.
The following are eight recommended design tips to achieve interoperability through integration when designing open systems.1 Identify, and then identify again
For successful implementation of system integration, a series of steps must be followed. Many facilities require internal and external resources. Therefore, facility managers should first seek corporate support of the concept—a champion, such as the board of trustees—that will buy into the aims of sharing system technology and the methodology to achieve it, and back up the program with funding.
Facilities then need to identify operating personnel who will be specifically dedicated to BAS. The formation of a dedicated BAS project team comprising on-site facility personnel and BAS design professionals is ideal. On-site personnel will be responsible for the implementation and operation of the BAS.
A knowledgeable design engineer who understands the needs of integrated systems design should be engaged to consult on and develop the design. It is also essential to determine the performance requirements—that is, what the facility wants to obtain for each system—as well as the overall performance level desired from system integration.
Design engineers working with facility managers need to help identify the systems that may be candidates for integration. These might include numerous systems that operate within their unique facility environment, such as lighting, elevators, ventilation, heating and cooling systems, electrical and emergency power systems, critical monitoring systems, life safety, and security systems.
Once the systems to integrate have been determined, design engineers working with facility managers must identify which strategies to employ to optimize system interoperability. This process includes defining and itemizing specific point information for key groups, and identifying what information is to be shared—what is essential to each system facility operator and what is extraneous.
Monitoring of various systems is another key decision. Which systems will be monitored as part of the integration process? Utilities can be metered and submetered, for example, to determine performance levels. In addition, how facility managers use integration to distribute energy costs properly must also be established. The design should allow for the partitioning of systems to attribute the correct costs to the various users and distribute the overhead among different branches of the facility’s operations. To make the integrated system function at its best, always consider monitoring system components by gauging its operating efficiency.2 Communication protocols
Communication protocols are the heart of interoperability. The optimum communication protocol for the project must be identified. This exercise should be done by an experienced design engineer or system integrator.
Currently, three chief standards have been established and are in wide proliferation within the building automation industry: BACNet, LonWorks, and Modbus. BACnet—Building Automation Control Network, one of the earliest attempts to allow systems to communicate on a single network—was developed to meet open protocol standards set by ASHRAE and currently is used by many equipment manufacturers.
LonWorks, developed independently by the Echelon Corp., is a protocol based on a neuron chip. Equipment containing this chip carries its unique characteristics and is able to communicate with the corresponding software in the automation system.
The Modbus protocol was developed by Modicon in 1979. Modbus uses a messaging structure to establish a master-slave and/or client-server communication link between different manufacturers’ equipment. It is widely used as a network protocol in the industrial manufacturing environment and is typically used as the de facto communication interface to emergency generators, modular chillers, power management, and supervisory control and data acquisition systems. All of these protocols can be used in conjunction with Transmission Control Protocol/Internet Protocol (TCP/IP).3 When in doubt, specify TCP/IP
TCP/IP is a communications protocol that binds everything on the Internet. Along with an ethernet communication cabling plant, it ensures that any building designed today will be ready for Internet technologies of the future. Incorporating this protocol into the design of the building’s infrastructure permits communication between systems not only within the building, but also over the Internet. It is especially desirable when dealing with multiple facilities. TCP/IP allows facilities to take advantage of all new developments occurring in research and Web-based technology.
Once TCP/IP has been specified, facilities can share data from different software packages that reside on the TCP/IP network. Data sharing is possible through the use of personal computers. Many system integrators use graphical user interfaces (GUIs) to visually share information from different systems on a single graphic video display. TCP/IP allows additional communication standards such as Open Database Connectivity (ODBC) and Open Process Control (OPC), along with Internet standards such as Extensible Markup Language (XML), Hypertext Markup Language (HTML), and Simple Object Access Protocol (SOAP).4 Design with connectivity in mind
Current technology allows disparate systems to converge onto an IP network. Thus, rather than using dedicated wires, many of these systems are able to tap into a communication network already installed and operated by the facility’s information technology (IT) group. An engineered structured cable plant allows several building systems, such as security, lighting control, and building automation, to share a single IT infrastructure. At the same time, each system communicates in a secure, independent manner.
This strategy takes advantage of the fact that data communications for many systems share the same communication protocol, such as the industry standard of Ethernet TCP/IP (IEEE standard 802.3). New direct digital control panels that reside on local area networks also can connect to the Internet using static IP addresses. As more building systems are designed to integrate with others, less cabling will be required, reducing initial installation costs and yearly maintenance. Buildings with extensive IT infrastructures reap the most savings when their existing IT network is used.5 Coordinate, coordinate, and then coordinate
Project coordination is a challenging, yet essential, task in any interoperability and integration project. Project coordination becomes immediately apparent when optimizing multiple systems to function in a holistic manner. Through coordination efforts, always seek to maximize existing resources while minimizing disturbances to facility occupants or visitors. Along with the traditional coordination of electrical power for control equipment, coordination efforts should also include:
Identifying project expectations: Make sure that all discussions and decisions are formally documented for all active parties to read and understand. Is system integration being considered to save energy or to standardize major building functions? Determine the driving factors through group discussion, and develop realistic goals. For instance, system integration does not have a direct correlation to energy reduction. Energy reduction control applications can be applied to an integration project.
Meeting with the IT department: When an existing IT infrastructure is anticipated, coordinate all data drops for each BAS panel or smart device. Provide floor plans to the IT department indicating all BAS panel locations. This will ensure that BAS connectivity to the existing faculty network will be allocated.
Identifying exact point mapping for all systems: Coordinate exact point information required from all equipment from each manufacturer that the BAS will monitor or control via a direct communicate interface. These direct communicate interfaces include protocols such as Modbus, OPC, and others. Make sure that essential information is obtained from each system manufacturer that will be integrated. Just because it is possible to obtain “100 points of information” from a chiller control panel through integration does not mean you should do it. Systems will not need every available point of information to be mapped from direct communication interfaces to operate efficiently.
Discussing GUI standards: Often, integration projects require that information from multiple manufacturers be visually displayed in a similar manner. This allows facility personnel to quickly familiarize themselves with different systems because “visually” information appears in a format they recognize. Always coordinate “how” different systems will be displayed. Design engineers should always request GUI screen samples in contract specifications.6 Capitalize on advance technologies
Wireless products based on IEEE-802.11b (WiFi radio frequency communications) are gaining acceptance as applications are being developed for its use. Current trends in the design of BAS are to incorporate the use of common communication software typically used in the IT world, such as XML or simple network management protocol. These software communication packages help manage BAS network alarms. The use of IT-related communication software allows for nontraditional systems to be interfaced and to share facility IT enterprise standard database applications such as Structured Query Language, widely used for querying and modifying data on a network enterprise level. Power over Ethernet (PoE) technology has created a host of new products for “smart devices” that have IP network connectivity, but require low-voltage power for operation. Applications include wireless closed-circuit TV cameras, security access control, lighting control, and control and monitoring of HVAC equipment. The number of products that use PoE connectivity at the device level is growing. This application reduces the need to install low-voltage wiring traditionally needed for many of these systems, reducing overall installation costs by approximately 80%. IEEE currently is defining a higher powered PoE standard, which would allow for about 30 to 50 W to be delivered to smart devices. The ability to provide more power to smart devices for PoE will invoke even greater interoperability and system integration applications in the near future.7 Roles and responsibilities
A roles and responsibilities chart helps identify all parties and individual roles on any integration project. This simple chart reduces misinterpretations by identifying all parties that will provide hardware and software, install network equipment and cabling, perform system integration design, perform system integrated testing and commissioning, and complete training and periodic maintenance for system adds or deletions. The chart should identify who will perform testing to ensure that all systems slated for integration are functioning as intended.8 Final tip
Opportunities for system integration and interoperability can be designed into new buildings or retrofit into older buildings, taking into account the age of existing equipment and calculating the cost-benefit ratio. In considering system integration, always think in terms of installing a system with a long life. The network communication infrastructure selected should have the capability to take advantage of cutting-edge technology, even if a facility’s current equipment is less advanced. Since many facilities must remain alert to productivity and operating costs, each BAS investment must have value for the future.
A design template that provides for the newest technology using open protocol communications will permit various systems to be integrated, while helping to lower overall operating costs. Such a design allows for interaction among the equipment of multiple manufacturers and permits dynamic monitoring of all critical functions at several different locations internally and externally from a facility, ensuring that systems will operate as efficiently as possible while alerting operations staff to problems as soon as they occur.