One “corporate guy,” who responded to our survey, connects through historians. “We have many mills, and each do different things,” he says. “Newer, large installations funded by corporate try to make the existing work with the new. All of our DCSs have their own historian that records everything, and they all have PI interfaces that run independently of the DCS historian. These also collect data via OPC in mills with multiple DCSs. Most mills have two layers of connectivity, but the new security model has three layers: process control, manufacturing, and business.”
According to our survey, 56% of our respondents did enterprise integration themselves, and 37% had a control system vendor do it.
WHAT THEY SAY
Cawley concurs. “You’ll probably need either an in-house or an external systems consultant to design and configure usable systems,” he cautions. “These systems typically require a level of system view and integration experience that isn’t usually resident in the control engineering staff. This also is true because many manufacturing companies have seriously reduced their ability to perform these integration tasks with existing staff. But, as long as the integration is standards-based and doesn’t require significant amounts of custom programming, it will be maintainable and can be adapted to changing conditions.”
One user responding to the survey reported setting up a special processor, which only gathers data from different PLCs and sends it upstairs. “The physical link is via the proprietary network of the PLC manufacturer,” he explains. “The processor, a PLC with Ethernet capability, connects via the factory LAN to a server that collects the data. Using SQL software, this data is formatted for display on PCs, replacing the manual log-sheet. This same software can generate reports with summaries of the data that was gathered.”
Kennedy also suggests setting up a dedicated server. “First, mirror the data into the IT environment because this integration doesn’t occur at the plant floor,” he advises. “You then have to build a server that can interpret the transactions, aggregate the information, and send it to the ES. We make a product called RLINK that does this. SAP makes a complete infrastructure, and just bought Lighthammer to add some applications to make this easier. No other software needs to be added because all process control systems already come with the interfaces to talk to the modules that mirror the information into the IT space.”
If you don’t have this capability in your system, other solutions are available, he says. “SAP has a program for certifying interfaces, and the vendors that provide this are on their web site. There are other ways of interfacing, such as sending data to the database that SAP uses, but now you’ll need mainframe consultants to get into SAP. I would advise users not to attempt this on their own.” Other software solutions we found include:
- Wonderware, which provides ISA S95-compatible XML standards to connect its ArchestrA architecture to SAP’s NetWeaver;
- Progilent, from Averna Technologies, which uses National Instrument’s LabView software to gather data and connect it with a variety of ES and plant floor systems;
- Informance’s, which uses a “hub and node” architecture to connect ES in a central location to local plants; and
- InduSoft’s Web Studio HMI/SCADA software, which provides direct access to standard SQL databases.
Martin of Invensys says standards also will help with integration. “Emerging standards such as ISA S95, MIMOSA, and OPC play an important role in creating a unified system by providing flexible, yet robust and secure interoperability between disparate systems and applications,” he explains. “S95 provides the appropriate schema for operations data. MIMOSA provides the schema for maintenance data. OPC provides the messaging services at the plant level. And open technologies such as Microsoft Corp.’s BizTalk provide communications services between plant and enterprise applications.”
Berge of SMAR likes OPC. “OPC-XML-DA and OPC-UA are creating a market in which plants and service providers all use the same technology, thus enabling advanced control, optimization and asset management to be done remotely by third-parties at market-based prices,” he says. “In the past the remote application was almost always a ‘dumb’ web browser that only displayed data. Seldom or never was there any application that did something clever with the data such as process optimization. With OPC-UA, it’s much easier to tie in "intelligent" applications that can receive data, process it, and send it back across the web.”
ES Work Goes Ever On
There is no end to enterprise integration. Next year, there may be a new ES package that needs to be integrated, or another Y2K/SOX “crisis” for you to deal with. As the “corporate guy” puts it, “While the process control side of the activity has long been prepared for this, we’ve been ‘installing’ SAP for several years. So far, very little useful information has been moved from our process control systems into SAP.”
Still, the potential benefits for enterprise integration can help make your plant more economical, efficient and profitable, so management will keep the plant open and you get to keep your job.