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Simulation based engineering—from process engineering to automation engineering
16th European Symposium on Computer Aided Process Engineering and 9th International Symposium on Process Systems Engineering W. Marquardt, C. PanteUdes (Editors) © 2006 Pubhshed by Elsevier B.V.
Simulation based engineering - from process engineering to automation engineering Horst Fischer,^ J.-Christian Toebermann,'' "Siemens AG, Industrial Solutions and Services, 91502 Erlangen, Germany ^Siemens AG, Region Deutschland, 52066 Aachen, Germany Abstract Automation systems and their engineering are essential for an economic and safe operation of a plant and make up a significant portion of the total cost for a new plant. Nevertheless it is common practice to work on process design, plant design, automation design and operational concept in separated ways. In general, information is passed on to the next work package in paper form only. Simulation based (automation) engineering means an approach to support a more continuous engineering workflow and a more integrated process view. In this paper we will outline corresponding developments and trends to reduce time and cost in automation engineering. Keywords: Simulation, Automation, Integration, Workflow. 1. Introduction Automation systems and their engineering make a portion of up to 25% of the total cost for a new plant in the process industries [1]. Additionally, both the automation and the operational concept play a very significant role besides the process design to achieve an economic and safe operation of a plant. Nevertheless it is common practice to work on process design, plant design, automation design and operational concept in separated ways. In general, information is passed on to the next work package in paper form only. Accordingly, the automation concept is developed and tested on this basis, even if modeling and simulation was already done in process design. How well process design and automation design matches is then not determined until the commissioning phase with the risk of significant delays and extra cost. This situation is unsatisfactory, in particular because use of simulation in process design is common practice - at least steady-state simulation is standard and also dynamic simulation is more and more applied. However, a more common view on process and automation and their integration within one simulation is not a new task. Several typical approaches exist: • Operator Training System (OTS) [2, 3] as simulation system for a specific plant with a dedicated modeling of process and automation behavior. Unfortunately, the dedicated modeling approach leads to high cost and is obviously unsuitable to support the usual engineering workflow • Extended use of dynamic process simulation: it is common usage to model at least control structures in a dynamic process simulation (e.g. Hysys OTS, Aspen Dynamics). However, the automation system part must then be manually reimplemented in the "real" automation system • Extended use of automation test system: it is possible to model basic process behavior in the automation system, e.g. PLC programs. This becomes difficult for
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H. Fischer and J.-C. Toebermann
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complex process behavior and leads always to "re-inventing" part of the process simulation • Combined use of process simulation and automation simulation system coupled to each other via an interface, e.g. OPC-variables The last approach is most promising. The interface is simple, defined, and easily adaptable and the approach offers: • use of the common tools for process design and automation engineering • efficient coupling for an integrated simulation, e.g. to evaluate conceptual designs, to discuss HMI faceplate information during a running process, etc. • extension to an OTS is also readily possible - without changes to the original automation engineering and process simulation Following this approach, we use our simulation platform SIMIT [4] as base tool for simulation based engineering. Besides its own simulation engine STMT has interfaces to different engineering environments, supports standard interfaces, is scalable, and integrated within the SIMATIC automation engineering (Fig. 1).
Automation engineering
Automation engineering oriented process simulation
||*^««iiiite1
Process design oriented process simulation
Figure 1: Simulation architecture with SIMIT 2. Developments and trends In practice the advantages of using such a simulation system are clearly proven. However there is still reluctance observed to actually make use of simulation in medium and small projects. This is due to some obstacles: the necessary effort to set up a simulation, process simulation sometimes does not exist, and bridging the gap between process and automation engineering needs interdisciplinary work of different engineering departments or even different suppliers. In the following, we will outline developments and trends to reduce or overcome some of these obstacles.
Simulation Based Engineering
1475
2.1. Thermodynamics and physical properties within automation simulation Often an appropriate process simulation is not available. For example Fig. 2 shows parts of a multistage discharge system. In the reactor a gas-/solid reaction occurs. The solid product is then transported via the network to the product chamber. Because no reaction, no recycle and no other change of material properties occurred, a process simulation was not done. However, discharging the hot and pressurized material properly was a significant issue. For this purpose the thermodynamic state equations of the gas/solid-system had to be integrated in the automation simulation system, either via an extensible modeling language or by properly linking a thermodynamic package. In the actual project the powerfiil modeling language of SIMIT was used. However, to reduce effort in ftiture projects, alternatives to integrate thermodynamic packages are investigated. Consequently, thermodynamic aspects become relevant and solvable also for automation simulation systems, i.e. the clear boundary between process and automation simulation is going to dwindle.
Figure 2: Discharge System 2.2. Generation of simulation model In practice the effort to setting up a simulation system should be as small as possible. In particular much necessary information exists already in other systems. The generation of lO-information for the gateway to the automation system is standard. Also the generation, parameterization and linking of simulation typicals based on typicals and additional information of the automation system is nowadays standard. Beyond that, XML is also a generally available information exchange format. Further parsing makes it possible to use the standard XML-Import to generate also the skeleton of the process-oriented part of the automation simulation system and where applicable, the interface to an additional process simulator. The effort to set up a simulation system therefore strongly decreases - making such simulation system profitable also for medium to small projects. 2.3. Integrated system for design, engineering and simulation The workflow between design, engineering and simulation can be further simplified by extended integration. For example as an add-on to our simulation environment we
H. Fischer and J.-C. Toebermann
1476
developed a tool for a process engineer to design technology documents (similar to P&I flowsheet) [5], Fig. 3. The results are being used to generate an automation system, i.e. hardware planning and a skeleton pic program, and in a second step to generate a simulation project for the plant behavior. Changes within a subsystem are propagated to the other subsystems. The automation system and the simulation system can be used together to simulate and evaluate the interaction of the automation and the plant. This way the technology expert can already easily check the feasibility of plant concepts and the automation engineer gains a dependable test object. A first prototype was successfiilly used in some pilot projects.
Automation system (HW, SW) generation
Simulation system change propagation
Figure 3: Workflow within the design, engineering and simulation systems
3. Conclusions Simulation based (automation) engineering means an approach to support a more continuous engineering workflow and a more integrated process view. A simulation environment allows the (re-)use of models and data from the design phase, through automation engineering and the start-up phase up to the production phase. Tasks like controller tuning, production planning and validation of quality management or manufacturing execution system can also be tackled within the simulation environment. All this leads to shorter commissioning phases and improved quality and plant efficiency. The interest, especially of plant owners, in such integrated systems is increasing. However, in practice an easier and more automated integration of subsystems is still desirable. We discussed actual developments and trends to reach this goal. Major improvements are already achieved.
References 1. 2. 3. 4. 5.
H. Schuler, CIT plus, 12-2003,4 A. Kroll, atp, 45, 02-2003, 50 A. Kroll, atp, 45, 03-2003, 55 http://www.siemens.com/simit European Patent Application No. 05007417.8
Simulation based engineering - from process engineering to automation engineering Horst Fischer,^ J.-Christian Toebermann,'' "Siemens AG, Industrial Solutions and Services, 91502 Erlangen, Germany ^Siemens AG, Region Deutschland, 52066 Aachen, Germany Abstract Automation systems and their engineering are essential for an economic and safe operation of a plant and make up a significant portion of the total cost for a new plant. Nevertheless it is common practice to work on process design, plant design, automation design and operational concept in separated ways. In general, information is passed on to the next work package in paper form only. Simulation based (automation) engineering means an approach to support a more continuous engineering workflow and a more integrated process view. In this paper we will outline corresponding developments and trends to reduce time and cost in automation engineering. Keywords: Simulation, Automation, Integration, Workflow. 1. Introduction Automation systems and their engineering make a portion of up to 25% of the total cost for a new plant in the process industries [1]. Additionally, both the automation and the operational concept play a very significant role besides the process design to achieve an economic and safe operation of a plant. Nevertheless it is common practice to work on process design, plant design, automation design and operational concept in separated ways. In general, information is passed on to the next work package in paper form only. Accordingly, the automation concept is developed and tested on this basis, even if modeling and simulation was already done in process design. How well process design and automation design matches is then not determined until the commissioning phase with the risk of significant delays and extra cost. This situation is unsatisfactory, in particular because use of simulation in process design is common practice - at least steady-state simulation is standard and also dynamic simulation is more and more applied. However, a more common view on process and automation and their integration within one simulation is not a new task. Several typical approaches exist: • Operator Training System (OTS) [2, 3] as simulation system for a specific plant with a dedicated modeling of process and automation behavior. Unfortunately, the dedicated modeling approach leads to high cost and is obviously unsuitable to support the usual engineering workflow • Extended use of dynamic process simulation: it is common usage to model at least control structures in a dynamic process simulation (e.g. Hysys OTS, Aspen Dynamics). However, the automation system part must then be manually reimplemented in the "real" automation system • Extended use of automation test system: it is possible to model basic process behavior in the automation system, e.g. PLC programs. This becomes difficult for
1473
H. Fischer and J.-C. Toebermann
1474
complex process behavior and leads always to "re-inventing" part of the process simulation • Combined use of process simulation and automation simulation system coupled to each other via an interface, e.g. OPC-variables The last approach is most promising. The interface is simple, defined, and easily adaptable and the approach offers: • use of the common tools for process design and automation engineering • efficient coupling for an integrated simulation, e.g. to evaluate conceptual designs, to discuss HMI faceplate information during a running process, etc. • extension to an OTS is also readily possible - without changes to the original automation engineering and process simulation Following this approach, we use our simulation platform SIMIT [4] as base tool for simulation based engineering. Besides its own simulation engine STMT has interfaces to different engineering environments, supports standard interfaces, is scalable, and integrated within the SIMATIC automation engineering (Fig. 1).
Automation engineering
Automation engineering oriented process simulation
||*^««iiiite1
Process design oriented process simulation
Figure 1: Simulation architecture with SIMIT 2. Developments and trends In practice the advantages of using such a simulation system are clearly proven. However there is still reluctance observed to actually make use of simulation in medium and small projects. This is due to some obstacles: the necessary effort to set up a simulation, process simulation sometimes does not exist, and bridging the gap between process and automation engineering needs interdisciplinary work of different engineering departments or even different suppliers. In the following, we will outline developments and trends to reduce or overcome some of these obstacles.
Simulation Based Engineering
1475
2.1. Thermodynamics and physical properties within automation simulation Often an appropriate process simulation is not available. For example Fig. 2 shows parts of a multistage discharge system. In the reactor a gas-/solid reaction occurs. The solid product is then transported via the network to the product chamber. Because no reaction, no recycle and no other change of material properties occurred, a process simulation was not done. However, discharging the hot and pressurized material properly was a significant issue. For this purpose the thermodynamic state equations of the gas/solid-system had to be integrated in the automation simulation system, either via an extensible modeling language or by properly linking a thermodynamic package. In the actual project the powerfiil modeling language of SIMIT was used. However, to reduce effort in ftiture projects, alternatives to integrate thermodynamic packages are investigated. Consequently, thermodynamic aspects become relevant and solvable also for automation simulation systems, i.e. the clear boundary between process and automation simulation is going to dwindle.
Figure 2: Discharge System 2.2. Generation of simulation model In practice the effort to setting up a simulation system should be as small as possible. In particular much necessary information exists already in other systems. The generation of lO-information for the gateway to the automation system is standard. Also the generation, parameterization and linking of simulation typicals based on typicals and additional information of the automation system is nowadays standard. Beyond that, XML is also a generally available information exchange format. Further parsing makes it possible to use the standard XML-Import to generate also the skeleton of the process-oriented part of the automation simulation system and where applicable, the interface to an additional process simulator. The effort to set up a simulation system therefore strongly decreases - making such simulation system profitable also for medium to small projects. 2.3. Integrated system for design, engineering and simulation The workflow between design, engineering and simulation can be further simplified by extended integration. For example as an add-on to our simulation environment we
H. Fischer and J.-C. Toebermann
1476
developed a tool for a process engineer to design technology documents (similar to P&I flowsheet) [5], Fig. 3. The results are being used to generate an automation system, i.e. hardware planning and a skeleton pic program, and in a second step to generate a simulation project for the plant behavior. Changes within a subsystem are propagated to the other subsystems. The automation system and the simulation system can be used together to simulate and evaluate the interaction of the automation and the plant. This way the technology expert can already easily check the feasibility of plant concepts and the automation engineer gains a dependable test object. A first prototype was successfiilly used in some pilot projects.
Automation system (HW, SW) generation
Simulation system change propagation
Figure 3: Workflow within the design, engineering and simulation systems
3. Conclusions Simulation based (automation) engineering means an approach to support a more continuous engineering workflow and a more integrated process view. A simulation environment allows the (re-)use of models and data from the design phase, through automation engineering and the start-up phase up to the production phase. Tasks like controller tuning, production planning and validation of quality management or manufacturing execution system can also be tackled within the simulation environment. All this leads to shorter commissioning phases and improved quality and plant efficiency. The interest, especially of plant owners, in such integrated systems is increasing. However, in practice an easier and more automated integration of subsystems is still desirable. We discussed actual developments and trends to reach this goal. Major improvements are already achieved.
References 1. 2. 3. 4. 5.
H. Schuler, CIT plus, 12-2003,4 A. Kroll, atp, 45, 02-2003, 50 A. Kroll, atp, 45, 03-2003, 55 http://www.siemens.com/simit European Patent Application No. 05007417.8