System Integration

MTP standard accelerates DCS and PLC integration

Many production plant designs require integration of a distributed control system with multiple PLC-based subsystems. NAMUR MTP is a standardized configuration and communication method to facilitate integration between the two, while cutting the cost, time and risk of doing so.

Courtesy: Emerson

 

Learning Objectives

  • Learn how to use module type package (MTP) to bridge the gap between DCS and PLC control systems to more fully integrate plant assets.
  • Understand how NAMUR NE 148 establishes the concepts and specifications of MTP.
  • Discover several possible applications for MTP.

MTP Insights

  • Even if many areas of a plant are well-automated, if they are not effectively integrated together, performance efficiency and safety gains may not be fully achieved.
  • Module type package (MTP)is a technology recommended by NAMUR to modularize process plant automation and enable communication between DCS, PLCs and HMIs from different vendors.
  • MTP is designed specifically as a vendor-neutral description language for performing data, visualization and functionality integration between a main process control system and associated automated equipment systems.

While modern process manufacturing operations are usually heavily automated, they are often not as thoroughly integrated. This persistent problem has been characterized as “operational silos” or “islands of automation.” Certainly, both large and small plant areas can be well-automated, but if they are not completely integrated, then significant performance, efficiency and even safety improvements remain left by the wayside.

This situation exists for many reasons. Most units in a typical production process are controlled and monitored by a large distributed control system (DCS). But there are many skids, utilities and other OEM equipment—including product finishing and packaging systems—more appropriately controlled and monitored on a localized basis using programmable logic controllers (PLCs) and human-machine interfaces (HMIs). Both operating units and associated equipment can vary dramatically depending on their role and may be supplied by many different vendors, each of which standardize on a variety of automation platforms, complicating any integration efforts beyond the most minimal functional interfaces.

Traditional integration methods have involved manual data mapping, custom code and “handshakes” and hardwiring. Even these efforts may still require operators to consult many different control interfaces throughout a plant, instead of having clear and transparent top-level visualization in the control room.

Fortunately, modern system convergence and connected manufacturing initiatives have resulted in a new solution to make it easier and quicker to integrate DCS, PLC, and HMI systems. The technology is called Module Type Package (MTP), and it is recommended by NAMUR to modularize process plant automation.

Traditional integration challenges

As an example of why integration is important, consider a typical pharmaceutical facility using a DCS to control and monitor the primary processes, with many specialized PLC-controlled centrifuges forming part of a subsequent production step. A bare-bones approach might simply have the DCS command each centrifuge to run when needed, and then monitor whether the equipment is actually running.

However, a centrifuge has significantly more running, performance, tuning and diagnostic data, and perhaps other modes such as cleaning. Live data is important, but so is historized information. Without a more sophisticated interface, control room DCS operators have no visibility into any of this detailed operation, unless they visit the individual HMI for each centrifuge. This is difficult if there are just a few centrifuges, and it becomes increasingly impractical as the quantity of PLC-controlled equipment grows.

Traditional solutions required systems integrators (SIs) and control systems engineers to develop bidirectional communications between the DCS and PLCs of interest, and to then create DCS graphics, alarming, historical logging and other associated functions as needed. This type of work can be complex and expensive, and it also requires additional testing and commissioning. Suppliers and OEMs of the PLC-based equipment may object to providing open access into their systems due to concerns that performance could be compromised, along with issues related to protecting their intellectual property. Any changes must be manually performed on both ends, and then retested.

Improved approach delivers benefits

A more workable alternative is to create an environment where native and standard mechanisms exist to support the necessary integration and subsequent communication. PLC-controlled equipment, even complex examples, can supply the required integration configuration information via an export, and a DCS can interpret it via in import, so that users need only connect the two elements.

NAMUR NE 148 establishes the concepts and specifications of Module Type Package (MTP), which is designed specifically as a vendor-neutral description language for performing data, visualization and functionality integration between a main process control system and associated automated equipment systems. MTP lets users easily configure their PLCs with the right “hooks” needed for interacting with a DCS, and it provides a mechanism for joining the two, reducing integration duration and risk by eliminating many of the prototyping and integration steps required by traditional integration methods (Figure 1).

Figure 1: Traditional manual PLC/DCS integration methods (upper diagram) are time-consuming and may involve multiple iterations for complete implementation. MTP integration automates and simplifies the task. Courtesy: Emerson
Figure 1: Traditional manual PLC/DCS integration methods (upper diagram) are time-consuming and may involve multiple iterations for complete implementation. MTP integration automates and simplifies the task. Courtesy: Emerson

MTP is not an industrial communication protocol such as OPC UA, Modbus TCP, or PROFINET. Instead, it provides a means for presenting PLC-based information in a consistent way, concentrating on:

  • Process control

  • Safety and security

  • Alarm management

  • HMI graphics

  • Maintenance diagnostics

NE 148 defines two layers. The first and “lower” layer is the Process Equipment Assembly (PEA), where PLC-based skids and other subsystems live. MTP is used to export PLC configurations from the PEA and import them into the second and “upper” layer, which is the Process Orchestration Layer (POL), consisting of the DCS or other higher-level process automation host system (Figure 2).

Figure 2: Each piece of equipment within the PEA layer is described using a library of standard MTP objects. These are exported and then imported to the POL using an MTP utility embedded in the DCS. Courtesy: Emerson
Figure 2: Each piece of equipment within the PEA layer is described using a library of standard MTP objects. These are exported and then imported to the POL using an MTP utility embedded in the DCS. Courtesy: Emerson

Each PLC is called a Module, or a Package Unit. Once the export/import has taken place, each Module communicates with the DCS over a standard Ethernet architecture network using secure OPC UA to present their process data, HMI information, and more (Figure 3).

Figure 3: Skids and other PLC-controlled subsystems are part of the PEA, the lower section. Using MTP, they can communicate via a common architecture network with their respective DCS, and also with other parts of the network if desired. Courtesy: Emerson
Figure 3: Skids and other PLC-controlled subsystems are part of the PEA, the lower section. Using MTP, they can communicate via a common architecture network with their respective DCS, and also with other parts of the network if desired. Courtesy: Emerson

The standardized MTP library of data objects provides an easy and extensible way for developers to establish sophisticated integration, without the need for writing specialized code, or performing extensive research and testing. Besides reducing integration risk, an important result is that the effort to perform the integration can be reduced by half or more, and any required changes after commissioning are greatly simplified.

Integration advantages

MTP provides clear advantages for end users seeking to break down barriers among operational silos. These users now have an economical and reliable approach to designing new installations or upgrading existing operations. This approach provides completely integrated control and visibility, helping operators to be more effective. MTP also opens doors by supporting other data-driven efforts, such as analytics and connected manufacturing.

Skid and machine builder OEMs can leverage MTP to deliver future-proofed solutions, making them a preferred supplier for their end-user customers. OEMs generally prefer standardized automation designs, but they often must invest effort to produce customizable or fully bespoke systems tailored to individual customer specifications. Solutions based on MTP provide a way for OEMs to focus on the performance of their equipment, while enabling easy integration with any customer automation system.

Controls engineers and SIs tasked with integrating PLC-based equipment with a DCS will appreciate how MTP streamlines this work, while promoting quality and consistency, and reducing the likelihood of human error. A technology cutting the time of integration by half in many cases, and minimizing the overall cost, is a major win for all parties involved.

Although MTP is a vendor-agnostic and cross-platform technology, some PLC and DCS suppliers have taken an additional step to support their customers by incorporating platform-specific extensions (Figure 4). Standard MTP functionality is preserved, but when a single supplier can provide all the DCS and PLC platform elements, additional efficiencies can be built-in to provide additional advantages for end users.

Figure 4: Emerson’s MTP-capable DeltaV DCS and PACSystems RX3i PLCs are examples of products which meet basic vendor-agnostic NAMUR NE 148. Courtesy: Emerson
Figure 4: Emerson’s MTP-capable DeltaV DCS and PACSystems RX3i PLCs are examples of products which meet basic vendor-agnostic NAMUR NE 148. Courtesy: Emerson

One example is that when PLC data structures are imported into the DCS, they can be handled in a way that optimizes the signal assignments within the DCS. This is because these automation platforms are already tested to work together right out of the box, over and above the basic NAMUR NE 148 requirements, and can therefore deliver additional consistency and capabilities.

One chemical manufacturer launched a program to build a new manufacturing unit. To expedite construction, the design called for many packaged subsystems, such as filtration skids, chemical injectors, natural gas-fired heaters with NOx suppression and a spray dryer. Instead of pursuing a costly and lengthy traditional integration approach, the team specified MTP-enabled automation systems across the board, predominantly from a single supplier (Figure 5).

Figure 5: When a chemical manufacturer built a new production unit by specifying Emerson’s MTP-capable DeltaV DCS and PACSystems RX3i PLCs, they benefited from advanced integration, while expending only half of the effort typically involved with traditional methods. Courtesy: Emerson
Figure 5: When a chemical manufacturer built a new production unit by specifying Emerson’s MTP-capable DeltaV DCS and PACSystems RX3i PLCs, they benefited from advanced integration, while expending only half of the effort typically involved with traditional methods. Courtesy: Emerson

MTP minimizes DCS/PLC integration time, costs and risks

Integration within modern production plants is imperative to provide operational efficiencies, while enabling other advanced capabilities like analytics and proactive maintenance. MTP is an innovative breakthrough to reduce the time, cost and risks associated with integrating PLC equipment with a plant DCS (Figure 6).

Figure 6: DCS and PLC integration based on MTP delivers many execution benefits, including speeding the time-to-market for new and retrofit projects. Courtesy: Emerson
Figure 6: DCS and PLC integration based on MTP delivers many execution benefits, including speeding the time-to-market for new and retrofit projects. Courtesy: Emerson

Greater modularization leads to increased flexibility, and standardized interfaces simplify development and operation. MTP-capable systems help users eliminate complex prototyping, while shortening the highly critical integration, testing, startup and commissioning steps. End-users, OEMs, and SIs will find additional benefits when they can select PLC and DCS platforms that are not only MTP-enabled, but are also provided with optimized extensions to streamline the effort.

Keith McNab, director, control and automation software, Emerson. Edited by David Miller, Content Manager, Control Engineering, CFE Media and Technology, [email protected].

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Keywords: MTP, Interoperability

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