"Our customer's Facility Management System (FMS) was an island of automation with all its data locked inside," says Richard K. Warner, PE, president, O & M Engineering, Inc. "We wanted our customer's FMS to be more flexible and effectively utilize the data it could generate, but we couldn't figure out a way to do it without scrapping substantial sections of the old FMS infrastructure and spending a fortune in the process."
Early generations of the Metasys® system were capable of handling only a handful of field devices because of limited memory and CPU capacities. Due to these limitations, a typical large building required multiple Metasys® systems. While newer generations have been developed that are much more capable, it is cost prohibitive for customers to upgrade on a one-for-one basis or to completely reengineer a working installation.
"We looked into installing a whole new system, but the cost verses benefit analysis didn't support it," Warner said.
The traditional approach to installing Metasys® systems is to hard wire the N2 bus with serial cable throughout a facility. This works, but many times the cabling required is redundant to networks already in place, and it's an even bigger problem in retrofit applications or historic property installations. Utilizing the existing infrastructure is much more cost effective and less intrusive to the property, especially when long cable distances are involved. (Shown here, Metasys test lab at The S4 Group; Adam 4571 Serial Server is being used to extend the N2 bus over Ethernet.)
Another problem with traditional Metasys® N2 bus installations is that support for remote or small buildings require the installation of another complete Metasys® system -- a move much too expensive for many to consider. Using the existing Ethernet infrastructure and supporting the remote building from the main facility makes more sense.
The S4 Group, led by managing partner Steve Jones, offered a solution to this problem.
"The solution we came up with we call the 'N2 Router.' It's a turnkey appliance that extends RS-485 N2 field bus over existing Ethernet infrastructure," says Jones. It utilizes Advantech Corp, Industrial Automation Group's UNO-2059 Industrial Computing platform and Advantech's ADAM-4571 modules to extend the network.
Advantech Corp, Industrial Automation Group's UNO-2059 was chosen for the N2 Router product family platform because it provides the needed CPU and memory for the project and multiple ports with built-in support for RS-485 needed for most installations. (Pictured, the N2 Router hosted on an Advantech UNO 2059.)
Advantech's UNO-2059 is a 586-grade platform that offers USB and PC Card interfaces to fulfill I/O device expansion needs. In addition, its four RS-232/485 ports with auto flow control make it an ideal solution for large computing, communication, and I/O expansion requirements as in S4's application. And because HVAC products are 24 Vac, it is important that Advantech offers a 24 Vac power option for the UNO platform to maintain consistency with existing environments.
"With the N2 Router in place, users have the ability to introduce new third party technology for supervisory control, HMI, reporting, trending, archiving, et cetera," says Jones. "They can add the benefits of best of breed solutions while retaining their investment in their existing Metasys® field gear."
The N2 Router merges legacy N2 networks into one logical network, allowing the users to use one centralized current generation supervisory controller and keep up with current Metasys® technology without spending a fortune. In addition, the N2 Router can logically merge multiple physical N2 networks into one logical N2 network, taking care of address mapping to avoid duplicate addresses. This feature makes it cost effective to bring new technology into older generation Metasys® systems without having to recable or reprogram existing unitary and application-specific controllers.
"S4's setup automatically discovers all field devices on the N2 bus and maps point names to upstream OPC, BACnet, or SNMP interfaces in a way that reflects the HVAC application running in the unitary or application-specific controller," said Larry Odegaard, vice president of technology, Facility Technology Solutions. "At the same time it is completely transparent to the existing Metasys® supervisory controller so Metasys® services and user interfaces will continue to function as they always have." (The N2 Router user interface, shown here, is clear and easy to navigate; remote administration allows large, complex networks of N2 Routers to be easily managed.)
When more ports are needed or the N2 bus needs to be extended over their Ethernet network, S4 uses Advantech's ADAM-4570 and 4571 models as a gateway between RS-232/422/485 and Ethernet interfaces.
S4 designed a cost-effective and feature-rich solution for enhancing and extending existing Metasys® systems, upgrading legacy Metasys® systems to newer technology, or migrating Metasys® systems to third party or competitors' BAS environments while retaining and protecting as much investment as possible.
"Our customer's FMS isn't an island of automation with all the information locked inside anymore," says Warner. "We now have visibility to that data and can use it for energy management and other decision-making processes."
