Simulation of a PCS 7 stirred tank reactor with SIMIT Simulation Framework

Transcription

1 Application description 06/2014 Simulation of a PCS 7 stirred tank reactor with SIMIT Simulation Framework SIMIT Simulation Framework V8.0, PCS 7 V8.0 SP2

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3 Table of contents Table of contents Warranty and liability Task description and solution Task Solution Simulation of the stirred tank reactor unit with jacket cooling Overview of the complete solution Core functionality Description of the individual functions Hardware and software components Basics - Process Technology Stirred tank reactor Signals Simulation of devices Process simulation Mass balance Fill level Heat balance Pressure Design and principle of operation Project structure Structure of the models (standard library) Device level Process level Simulation of inflows Simulation of the fill level Pressure simulation Simulation of temperature Launching the application example Preparation Commissioning Operating the application Overview Scenario A: Change of temperature of the inflows Scenario B: Change the material properties of an inflow Scenario C: Change via the visualization interface History Entry ID: , V1.0, 06/2014 3

4 1 Task description and solution 1 Task description and solution 1.1 Task A PCS 7 project for a system grows in complexity due to the increasingly important requirement of availability and individuality of the system. For this reason, extensive tests are carried out to test the automation program. To make this possible one needs particular system states and feedback from actuators and sensors with which one can check whether the automation program behaves correctly. The provision of feedback or the system state is very laborious or not possible without a suitable tool. For this reason, nowadays one can find tools such as SIMIT Simulation Framework (further referred to as SIMIT), which simplify the simulation of signals, devices and process states in a significant way. 1.2 Solution Simulation of the stirred tank reactor unit with jacket cooling This application example describes how to use the SIMIT simulation software to easily and quickly create the required simulation for your PCS 7 project. A stirred tank reactor is used as a simulated unit. This is based on the "stirred tank reactor" PCS 7 Unit Template. The technical description of the "stirred tank reactor" unit can be found in the documentation for the "stirred tank reactor" PCS 7 Unit Template. These can be found in the Siemens Industry Online Support portal under the Entry ID The following adjustments have been made to the "stirred tank reactor" Unit Template: Migration to PCS 7 V8.0 SP2 Removal of the Continuous Function Charts, used for simulation without SIMIT Expansion of the hardware configuration by analog and digital input and output modules Creation of a symbol table Interconnection of the channel blocks of the measuring points with the corresponding symbols from the symbol table The application example provides a template which includes the simulation of important physical processes, devices, and signals of a stirred tank reactor. The installation is modular and is based on physical principles. Its utilization offers the following advantages: A reduction of the knowledge necessary to develop simulations A decrease in the configuration effort Flexible installation and adjustment Standardized structures Entry ID: , V1.0, 06/2014 4

5 1 Task description and solution Overview of the complete solution Scheme The following figure shows a possible style depth of a simulation solution of a stirred tank reactor with a graphical user interface. Figure 1-1: Visualization interface with parameter windows (1) and status display (2) 1 2 Description The "stirred tank reactor" simulation example includes several prefabricated, unified and ready-connected device and process simulations. Using this sample solution as a basis, numerous instances with different parameter assignments can be generated with adapted characteristics to be widely integrated in simulation solutions. The simulation of the stirred tank reactor is accomplished as a SIMIT project in three levels: Signal level Device level Process level In the signal level, system signals are defined and scaled with the help of the symbol table (export from PCS 7). In the device level, devices such as valves and motors are defined and connected to the respective signals of the signal level via connectors. In the process level, physical processes such as material flows are modeled on the basis of states (e.g. valve position) and other parameters (e.g. maximum flow). 1 Entry ID: , V1.0, 06/2014 5

6 1 Task description and solution Differentiation Required experience The present simulation solution is intended for reactors in continuous operation. Physically speaking, the technical process is illustrated in a simplified way by assuming ideal conditions. Fundamental knowledge of the following specialist fields is a prerequisite: Basic knowledge of process technology Basic knowledge of physical modeling Engineering with SIMATIC PCS 7 and Advanced Process Library (APL) Knowledge of control technology Core functionality The individual components of the stirred tank reactor simulation are described in the following. The entry point is the visualization interface of the "stirred tank reactor" simulation model. Figure 1-2 visualization interface Visualization interface The visualization interface of the stirred tank reactor simulation consists of the following components: Schematic representation of the stirred tank reactor with inflow components (arranged to the left of the reactor) and outflow components (arranged to the right of the reactor) Text boxes for entering simulation parameters (e.g. temperature coefficients, specific densities,...) The visualization interface provides the user with an overview of the entire simulation and allows him to change parameters in order to test the response of the automation program for state changes. Entry ID: , V1.0, 06/2014 6

7 1 Task description and solution Procedure The following representation describes the procedure of how to create a simulation model with SIMIT. Figure 1 3 Creating a simulation model Entry ID: , V1.0, 06/2014 7

8 1 Task description and solution Description of the individual functions Signals The following illustration shows the coupling editor for signal definition. Figure 1-4: Definition of signals Signals that are required as an interconnection between the simulation model and automation are defined in the coupling editor. They can be created manually or with the aid of an exported symbol table. The advantage of importing the symbol table is that it is faster and that the data types, symbolic names and addresses match with those in the automation system (lower risk of errors). Devices The diagram below shows the simulation of a pump as an example. Figure 1-5: Simulation model of a pump The devices are built with the aid of the provided SIMIT components. SIMIT offers pre-made components that are tailored to the drive function blocks of the APL. Devices can be created manually or with the aid of the SMD import function. During the SMD import, the data that was exported from the PCS 7 project using the Import/Export Assistant is combined with the valve and engine templates. The templates can be customized to specific users. Entry ID: , V1.0, 06/2014 8

9 1 Task description and solution Note You can find information regarding the SMD import together with the templates under chapter 4.3 "The IEA Import" of the manual "SIMIT (V8.0) Operating Manual". Physical processes The following diagram shows the simulation of a volume flow as an example. Figure 1-6: Simulation model of an inflow Additional functions The physical processes are created in the application example using components from the standard library. The values to be processed come from simulated devices, signals, simulated processes, or they are constants. The results of the calculations are passed on to devices, signals or other simulated processes with the aid of global connectors. The simulation example of the stirred tank reactor contains additional scripts. These scripts help defining the the initial state of the simulation or, for example, changing the temperature of the inflows to predetermined values. Scripts have the advantage that by using them one can set defined system states automatically. Note For information about creating scripts, please refer to chapter 6 "The Automatic Control Interface (ACI)" of the "SIMIT (V8.0) Operating Manual". Besides the simulation with standard components, the model of the stirred tank reactor is additionally realized with a customized component type. This was created with the Component Type Editor (CTE). In order to create customized component types with the Component Type Editor, you need an appropriate license. Note For information regarding the creation of customized component types, please refer to the "SIMIT Component Type Editor" manual. Entry ID: , V1.0, 06/2014 9

10 1 Task description and solution 1.3 Hardware and software components The application has been created with the following components: Hardware components Table 1 1 Component SIMATIC PCS 7 ES/OS IPC847C W7 Note For the PCS 7 V8.0 SP2 sample project and the SIMIT V8.0 sample project Note In case of different hardware, please take heed of the suggested hardware configuration for installing the software components. The suggested hardware configuration can be found in the Read Me file of the PCS 7. Standard software components Table 1 2 Component SIMATIC PCS 7 V8.0 SP2 S7-PLCSIM SIMIT Ultimate V8.0 Note SIMATIC PCS 7 V8.0 SP 2 is not a part of SIMATIC PCS 7 ES/OS IPC847C The license is not a part of SIMATIC PCS 7 ES/OS IPC847C The software and license are not a part of SIMATIC PCS 7 ES/OS IPC847C Note SIMIT V8.0 is offered in three versions: "STANDARD", "PROFESSIONAL" and "ULTIMATE". An overview of the contained modules is available in Chapter 1.2 "Product versions" of the manual "SIMIT (V8.0) Operating Manual". The modules "PLCSIM Coupling" and "Structured Model Diagrams (SMD)" are used in the application example. These do not form part of SIMIT V8.0 STANDARD but can be ordered separately. Entry ID: , V1.0, 06/

11 1 Task description and solution Samples files and projects The following list contains all files and projects that are used in this example: Table 1 3 Component Note _SIMITStirredTankReactor_PCS7V80SP2.zip PCS 7 V8.0 SP2 example project _SIMITStirredTankReaktor_V8.simarc _SIMITStirredTankReactor_de.pdf SIMIT V8.0 example project This document Entry ID: , V1.0, 06/

12 2 Basics - Process Technology 2 Basics - Process Technology 2.1 Stirred tank reactor 2.2 Signals The description of the process technology basics of the stirred tank reactor can be found in chapter 2.1 "stirred tank reactor" of the documentation for the PCS 7 Unit Template "stirred tank reactor". In order to pass the correct values to the simulation, the simulated signals must be scaled accordingly. Scaling is done via the "scaling", "lower scaling value" and "upper scaling value" columns of the coupling editor. Figure 2-1: Scaling the analog signals It is also possible to scale the signals from the signal properties window. Figure 2-2: Signal properties Even here, scaling is done via the "scaling", "lower scaling value" and "upper scaling value" fields. Entry ID: , V1.0, 06/

13 2 Basics - Process Technology The values for the scaling can be found in the hardware configuration of the PCS 7. You can find the values in the "measuring range" field ("output range" in output modules) of the "input" tab ("output" in output modules) in the object properties of the input or output modules. Figure 2-3 The values for the upper and lower scaling value can be read on the channel blocks in the PCS 7 project. To do this, open the CFC charts where the channel blocks of the measuring points to be simulated are placed. You can find the values for the upper and lower scaling values in the "Scale" input of the channel block. Figure 2-4 Note No scaling is necessary for boolean signals. Entry ID: , V1.0, 06/

14 2 Basics - Process Technology 2.3 Simulation of devices Motors/pumps The simulation of the used devices is described below. The default component "DriveP1" is used in the application example for the simulation of the pumps. For information regarding standard components, please refer to chapter "Pump and fan drives" of the "SIMIT (V8.0) Operating Manual". Valves The default component "DriveV4" is used in the application example for the simulation of the valves. For information regarding standard components, please refer to chapter "Valve drives" of the "SIMIT (V8.0) Operating Manual". Entry ID: , V1.0, 06/

15 2 Basics - Process Technology 2.4 Process simulation To simulate a process, an adequate process model must be set up before. Thereby, a compromise between accuracy and generality must be found. The more accurate a process model is built, the better the simulation results. However, an increase in the accuracy of the process model also entails an increase in its complexity. For this reason, a simplified process model is described in this application example. The individual components of the process model of the stirred tank reactor are described in the following. The entry point is the pipeline and instrument flow diagram (P&I flow diagram). The figure below shows the P&I flow diagram of the stirred tank reactor: Figure 2-5 FIC Quantity MV SP YC Quantity 1. Inlet FFIC Comp_1 YC Comp_1 2. Inlet 3. Inlet 4. Inlet Inertization TIC Reactor TIC Jacket FFIC Comp_2 FIC Catalyst YC Heat YC Comp_2 YC Catalyst YC In NS StirringMotor YC Out PIC Pressure LIC Level YC Depressurize Heating steam Product YC Cool Outlet Cooling water M NS PumpJacket Entry ID: , V1.0, 06/

16 2 Basics - Process Technology Assumptions and conditions The following assumptions/conditions are assumed for the stirred tank reactor shown in the figure: The stirred tank reactor possesses any geometry with ideal mixing and jacket cooling. Educts and additives are metered separately. In this process, the material flows can have an arbitrary time course. The temperature distribution inside of the reactor mixture is considered to be homogeneous. The spatial dependence of the coolant temperature (along the coolant flow in the tempering jacket) remains disregarded. The averaged jacket temperature from the input and output temperature is used instead of the temperature gradient in the cooling jacket. The heat capacity of the reactor wall (steel) is small when compared to the heat capacity of the reactor mixture and is therefore neglected. Heat dissipated from the cooling jacket into the environment is not modeled. The heat input from the stirrer or other secondary thermal effects are neglected. Entry ID: , V1.0, 06/

17 2 Basics - Process Technology Physical sizes The following table gives an overview of the physical sizes, which are technically detected or known. The units correspond to the measured values and must be still partially converted. Table 2 1 a physical quantity Formula symbols Unit Temperature of the reactor T R [ C] Temperature of the main component Temperature of the secondary component 1 Temperature of the secondary component 2 Temperature of the catalyst T cat [ C] Temperature of the jacket output Mean jacket temperature [ C] Volume flow of the main component Volume flow of the secondary component 1 Volume flow of the secondary component 2 Volume flow of the catalyst [l/h] Volume flow of the product [l/h] Volume flow input of inert gas Volume flow output of inert gas Mass flow of the main component Mass flow of the secondary component 1 Mass flow of the secondary component 2 Mass flow of the catalyst T q T c1 T c2 T J [ C] [ C] [ C] [ C] [l/h] [l/h] [l/h] Mass flow of the product Mass flow of the heating medium Mass flow of the coolant Mass flow input of inert gas Mass flow output of inert gas Entry ID: , V1.0, 06/

18 2 Basics - Process Technology a physical quantity Formula symbols Unit Weight of inert gas in the reactor Specific heat capacity of the main component Specific heat capacity of the secondary component 1 Specific heat capacity of the secondary component 2 Specific heat capacity of the catalyst Specific heat capacity of the product [] Fill level h [m] Heat flow of the main ² component ³ Heat flow of the secondary ² component 1 ³ Heat flow of the secondary ² component 2 ³ Heat flow of the catalyst ² ³ Heat flow of the heating ² medium ³ Heat flow of the coolant ² ³ Heat transfer between the ² cooling jacket and reactor ³ Reactor pressure p [ bar ] Reactor volume [m³] Gas volume [m³] Material volume in the reactor [m³] Reactor floor area [m²] Individual gas constant R s Heat transfer coefficient U [kg/s 3 K] Heat transfer area A RJ [m²] The balance equations can be set up under the above referenced assumptions, based on the known physical sizes and constants. Entry ID: , V1.0, 06/

19 2 Basics - Process Technology Mass balance The mass balance of the reactor can be determined on the basis of inflowing and outflowing masses. The mass flows can be determined with the aid of the volume flows and specific densities of the substances. The mass flow can be determined using the following formula: Table 2 2 Formula = Unit Therefore, the mass balance is the sum of the inflowing and outflowing mass flows: Table 2 3 Formula Unit Fill level = + = = = The fill level of the reactor can be determined with the aid of the input and output volumes and the geometric properties of reactor (volume, surface area). The volume and the floor area of the reactor are constants which can be tailored by the user of the application. In order to calculate the current fill level from the volume flow, the volume change has to be replaced with the following expression: Table 2 4 Formula = () Unit Entry ID: , V1.0, 06/

20 2 Basics - Process Technology When inserted in the volume flow equation and solved according to the fill level it gives: Table 2 5 Formula () = + () = 1 + () = 1 + Unit [] Heat balance The stirred tank reactor with cooling jacket is based on two heat balances: Heat balance of the stirred tank reactor Heat balance of the cooling jacket The heat balances are conservation equations, which are based on a defined area, the so-called balance space. Heat balance reactor The balance space of the reactor's interior is used for the heat balance of the reactor. Figure 2-6 shows the balance space of inflowing and outflowing heat flows. Figure 2-6 Entry ID: , V1.0, 06/

21 2 Basics - Process Technology The heat balance gives the following as a result: Table 2 6 () () Formula = + = Unit ² ³ The change of the stored heat in the reactor is proportional to its temperature change. The proportionality factor is the overall heat capacity C R of the reactor mixture, which consists of the mass and the specific heat capacity of the mixture. Therefore, the following applies: Table 2 7 () Formula = () Unit ² ³ In each case, the heat supply from the incoming material flows is given from the corresponding mass flow, the specific heat capacity and the temperature difference between the inflow and the reactor contents: Table 2 8 Formula = = ( ) = ( ) = ( ) Unit ² ³ The heat transfer to the cooling jacket is determined from the heat transfer coefficient U, the heat transfer area A and the difference between the reactor temperature and the mean cooling jacket temperature: Table 2 9 Formula = Unit ² ³ Entry ID: , V1.0, 06/

22 2 Basics - Process Technology In short, one can write the following about the heat balance of the reactor: Table 2 10 () Formula = + ( ) + ( ) + ( ) + Heat balance of the cooling jacket The cooling jacket itself is taken as a balance space for the heat balance of the cooling jacket. Figure 2-7 Based on figure 2 7, this conservation equation is given for the cooling jacket: Table 2 11 Formula () = + () = + + Unit ² ³ Entry ID: , V1.0, 06/

23 2 Basics - Process Technology The change of the stored heat in the cooling jacket is proportional to its temperature change. The proportionality factor is the overall heat capacity of the medium in the cooling jacket, which consists of the mass and the specific heat capacity of the medium. Therefore, the following applies: Table 2 12 () Formula = () Unit ² ³ In each case, the heat flow from the incoming material flows is given from the corresponding mass flow, the specific heat capacity and the temperature difference between the inflow and the cooling jacket contents: Table 2 13 Formula = ( ) = ( ) Unit ² ³ The heat transfer between the cooling jacket and the reactor corresponds exactly to the dissipated or supplied heat from the reactor: Table 2 14 Formula = Unit ² ³ In short, one can write the following about the heat balance of the cooling jacket: Table 2 15 () Formula = + + Entry ID: , V1.0, 06/

24 2 Basics - Process Technology Pressure In order to calculate the pressure in the reactor, one requires that portion from the total volume of the reactor, which is occupied by the inert gas (e.g. nitrogen). The gas volume is determined from the total reactor volume (constant) and the volume of the reactor contents (variable): Table 2 16 Formula () = () () = ( + ) Unit [ ] Furthermore, the pressure is dependent on the mass of the inert gas and the temperature in the reactor. The determination of the reactor temperature takes place as described in step The mass of the inert gas is determined as follows by the incoming and outgoing mass flows: Table 2 17 Formula Unit = + () = ( + ) [] The pressure p can now be determined with the aid of the thermal equation of state for an ideal gas. Table 2 18 Formula Unit = Entry ID: , V1.0, 06/

25 3 Design and principle of operation 3 Design and principle of operation Below you can find descriptions regarding the design of the project and the transformation of the individual physical models in SIMIT. 3.1 Project structure The following SIMIT project is divided into 3 parts: Device level Miscellaneous Process In addition to the three levels, it also contains the gateway to PLCSIM. Gateway The gateway defines the interface between PLCSIM and SIMIT. The definition is created by means of the coupling editor. The signals can be created manually or by using the SIMIT Import Wizard and the exported symbol table from PCS 7. When the simulation is active, you can read and change the current signal values in the coupling editor. Figure 3-1 Coupling editor during active simulation Current signal values 2. Symbolic signal names Note You can find a description on how to set up signals using the SIMIT Import Wizard and the symbol table in chapter "The PLCSIM coupling" of the "SIMIT (V8.0) Operating Manual". Entry ID: , V1.0, 06/

26 3 Design and principle of operation Miscellaneous The level "Misc" (Miscellaneous) is where supporting calculations for the calculation of temperature and the reactor's fill level are carried out. Furthermore, there is a diagram which contains analog connectors to further extend parameters to the process model or to input calculated values in the control system. Figure 3-2: "Connections" diagram The diagrams "Area_Jacket", "Density" and "Heat Capacity" are included for the calculation of the temperature and fill level. The area for the heat transfer between the reactor and cooling jacket is calculated in the "Area_Jacket" diagram. This depends on the current fill level of the reactor. Figure 3-3: "Area_Jacket" diagram Entry ID: , V1.0, 06/

27 3 Design and principle of operation The radius of the reactor is calculated in step 1, based on the floor area set-up of the reactor. The jacket area is then calculated in step 2, based on the radius and the current fill level (corresponding to the height of the area to be calculated). The sum of jacket area that depends on the fill level and the floor area (constant) gives the current area for the heat transfer between the reactor and the cooling jacket (step 3) The mean density of the resulting mixture is calculated in the "Density" diagram, based on the inflowing material. Figure 3-4 "Density" diagram 1 1 The individual, incoming material flows are set in proportion to the sum of all material flows. The resulting ratio is multiplied by the density of the inflowing material. The sum of the individual partial densities is assumed to be the density of the material mixture inside the reactor and passed on. The specific heat capacity of the mixture inside the reactor is calculated in the "Heat Capacity" diagram. The calculation is done using the mass ratios of the incoming materials and their specific heat capacities. The specific heat capacities of the inflowing materials are calculated with the aid of a macro ("Heat_Capacity"), which is described in more detail below. The sum of the specific partial individual heat capacities is assumed to be the specific heat capacity of the mixture. The specific heat capacity of the mixture is dependent on the temperature in the reactor. Figure 3-5 "Heat Capacity" diagram 1 1 The "Density" and "Heat_Capacity" diagrams help examine before and after the calculation of the density or the specific heat capacity, whether a division is created with a zero value or very small values, so that the system runs stable (identified with 1 in the image). Entry ID: , V1.0, 06/

28 3 Design and principle of operation 3.2 Structure of the models (standard library) Device level The device level is hierarchical. The hierarchy is derived from the technological hierarchy of the PCS 7 project. The device level contains all the actuators (pumps and valves), which are also present in the PCS 7 project. Figure 3-6 Comparison between the SIMIT and PCS 7 hierarchy A diagram is created in the corresponding hierarchy folder for each device. The structure of the diagrams for a valve is the same for all valves (excluding the associated signals). The structure of the diagrams for a pump is the same for all pumps. For this reason, a valve and a pump are described as an example in the application example. Entry ID: , V1.0, 06/

29 3 Design and principle of operation Valve The figure below shows the structure of the YC_Product diagram. This diagram helps simulating the reactor's outlet control valve. Figure 3-7 YC_Product diagram The diagram consists of the following components: 1. "Output" I/O connector 2. "Selection" analog switch 3. "MUL" multiplication 4. "DriveV4"-type valve drive 5. Global connector 6. "Input" I/O connector 5 6 The Output I/O connector is connected to the "PLCSIM YC_Product_MV" signal. In the device simulation, the manipulated variable, which is predefined by the automation system for the valve, is read through it. The read value is connected to an analog switch. During simulation, this allows switching between the predefined automation system value and an arbitrary value. The multiplier allows the predefinition of time, which should be required for opening and closing operation. In the application example, half of the monitoring time is spent on the valve block in the automation system. The "DriveV4" valve drive tracks the analog input value continuously. The tracking is dependent on the set opening or closing time (T Open or T Close ). The outputs of the valve drive can be connected to the inputs of global connectors and I/O connectors. The I/O connectors forward the simulated values (valve position, end positions) to the automation system. The global connectors serve to provide the simulated valve values to other diagrams, e.g. to calculate the current flow through a valve. Entry ID: , V1.0, 06/

30 3 Design and principle of operation Motor The figure below shows the structure of the "NS_Motor" diagram. This diagram helps simulating the drive of the reactor's mixing motor. Figure 3-8 NS_Motor diagram The diagram consists of the following components 1. "Output" I/O connector 2. "MUL" multiplication 3. "DriveP1"-type pump drive 4. Global connectors 5. "Input" I/O connectors The "Output" I/O connector is connected to the "PLCSIM NS_Motor_Start" signal. In the device simulation, the starting command from the automation system is read through it and interconnected with the latter. The multiplier allows the predefinition of time, which should be required for the acceleration and deceleration from standstill to the rated speed and back. In the application example, half of the monitoring time is spent on the motor block in the automation system. The pump drive simulates the starting and stopping of the motor. The feedback signals are connected to the global connectors and the "Input" I/O connector. The "Input" I/O connector is connected to the "PLCSIM NS_Motor_FbRun" signal and gives the feedback, whether the motor continues to run to the automation system. The simulated values can be forwarded to other diagrams via the global connectors. Entry ID: , V1.0, 06/

31 3 Design and principle of operation Process level The process level is hierarchical. The hierarchy is derived from the technological hierarchy of the PCS 7 project. The process level contains the simulations of temperatures, pressures, volume flows and the fill level of the stirred tank reactor. Figure 3-9 Comparison between the SIMIT and PCS 7 hierarchy A diagram is created in the corresponding hierarchy folder for each value to be simulated. Macros have been created for repetitive calculations such as volume and heat flows. These can be used as often as needed, which leads to a significantly reduced configuration effort. Macros The following macros are provided and used in this application example: "Heat_Flow_1" "Heat_Flow_2" "Heat_Capacity" "PerHoutToPerSecond" "PerSecondToPerHour" "Rate_of_temperature_change" "Flow" "T_Mean" Entry ID: , V1.0, 06/

32 3 Design and principle of operation "Heat_Flow_1" The "Heat_Flow_1" macro calculates the heat flow generated from an inflowing medium. The figure below describes the structure of the macro: Figure 3-10 "Heat_Flow_1" macro structure The macro has the following input variables: "currentmassflow" [kg/s] (current mass flow) "specificheatcapacity" [m²/s²*k] (specific heat capacity of the inflowing medium) "Temp1" [K] (temperature of the inflowing medium) "Temp2" [K] (temperature of the reactor contents) The "Heat_Flow_1" output of the macro is the "currentheatflow" current heat flow [kg*m²/s 3 ], caused by the temperature difference between the reactor contents and inflowing medium. The heat flow is calculated from the product of the corresponding mass flow, the specific heat capacity and the temperature difference. Entry ID: , V1.0, 06/

33 3 Design and principle of operation "Heat_Flow_2" The "Heat_Flow_2" macro calculates the heat flow generated from the heat transfer between the reactor and the cooling jacket. The figure below shows the structure of the macro: Figure 3-11 "Heat_Flow_2" macro structure The macro has the following input variables: "HeatTransferCoefficient" [kg/s³*k] (heat transfer coefficient) "ContactArea" [m²] (heat transfer area) "Temp1" [K] (reactor temperature) "Temp2" [K] (mean cooling jacket temperature) The "Heat_Flow_2" output of the macro is the "currentheatflow" current heat flow [kg*m²/s 3 ], caused by the temperature difference between the reactor temperature and the mean cooling jacket temperature. The heat flow is calculated from the product of the heat transfer coefficient, heat transfer area and temperature difference. Entry ID: , V1.0, 06/

34 3 Design and principle of operation "Heat_Capacity" The "Heat_Capacity" macro calculates the specific heat capacity of a medium at a specific temperature. The figure below shows the structure of the macro: Figure 3-12 "Heat_Capacity" macro structure The macro has the following input variables: "specificheatcapacityreftemp" [m²/s²*k]) (specific heat capacity of the medium at a reference temperature) "TempCoefficient" [m²/s 2* K 2 ] (temperature coefficient of the medium) "CurrentTemp" [K] (process temperature) "RefTemp" [K] (reference temperature) The "specificheatcapacitycurrenttemp" output of the macro is the specific heat capacity of the medium at the current process temperature [m²/s 2 K 1 ]. The specific heat capacity at the current temperature is calculated from the sum of the specific heat capacity at a reference temperature and the product of the temperature coefficient and the difference between the process temperature and the reference temperature. "PerHourToSecond" The "PerHourToSecond" macro converts the flows from "per hour" into "per second" (e.g. volume flow m³/h to m³/s). The figure below shows the structure of the macro: Figure 3-13 "PerHourToPerSecond" macro structure The input of the macro uses the "PerHour" unit (current per hour). The macro converts current per hour into current per second or current per minute by dividing the value by 3600 or 60. Entry ID: , V1.0, 06/

35 3 Design and principle of operation "PerSecondToPerHour" The macro has the following two outputs for the converted values: "PerSecond" (current per second) "PerMinute" (current per minute) An unused output can be set to invisible. The "PerSecondToPerHour" macro converts the flows from per second into per hour (e.g. m³/h in m³/h). The figure below shows the structure of the macro: Figure 3-14 "PerSecondToPerHour" macro structure The input of the macro uses the "PerSecond" unit (current per second). The macro converts this value into per hour or per minute by multiplying it by 3600 or 60. The macro has the following two outputs for the converted values: "PerHour" (current per hour) "PerMinute" (current per minute) An unused output can be set to invisible. Entry ID: , V1.0, 06/

36 3 Design and principle of operation "Rate_of_temperature_change" The "Rate_of_temperature_change" macro calculates the temperature change for each time unit (e.g. K/s). The figure below describes the structure of the macro: Figure 3-15 "Rate_of_temperature_change" macro structure The macro has the following inputs: Heat_Flow [kg*m²/s³] (heat flow in the reference area) "Mass" [kg] (mass in the reference area) "specific_heat_capacity" [m²/s ² K] (specific heat capacity of the reference material) The "rate_of_temp_change" output of the macro is the temperature change of the medium [K/s]. The temperature change is calculated by dividing the heat flow by the product of the mass in the reference area and the specific heat capacity of the reference material. Entry ID: , V1.0, 06/

37 3 Design and principle of operation "Flow" The "Flow" macro calculates the current flow rate through a valve with equal percentage characteristic (e.g. m³/h). The figure below describes the structure of the macro: Figure 3-16 "Flow" macro structure The macro has the following inputs: "currentvalveposition" [%] (current valve position) "maxflow" (maximum flow with a fully opened valve) The "currentvolumeflow" output is the current flow rate (e.g. m³/h). The current flow rate is calculated from the product of the maximum flow rate and the square of the division of the current valve position by 100. Entry ID: , V1.0, 06/

38 3 Design and principle of operation "T_Mean" The "T_Mean" macro calculates the mean temperature in the cooling jacket. The figure below describes the structure: Figure 3-17 "T_Mean" macro structure The macro has the following inputs: "Heating" [K] (temperature of the heating medium) Cooling [K] (temperature of the coolant) TicJacket [K] (temperature of the cooling jacket output) The "TMean" output is the mean temperature of the cooling jacket. The macro contains three calculations for the temperature: Mean value from the temperature of the heating medium and the temperature of the cooling jacket output Mean value from the temperature of the coolant and the temperature of the cooling jacket output Mean value from the temperature of the heating medium, the temperature of the coolant and the temperature of the cooling jacket output Thanks to comparative and logical operators, the macro checks if heating or cooling is in progress or none of them. Based on the result of this test, the corresponding mean value is switched through to the output. The throughconnection is done via a multiplexer. Entry ID: , V1.0, 06/

39 3 Design and principle of operation Simulation of inflows The simulation project of the stirred tank reactor contains the following inflows: "Catalyst" (inflow of the input material catalyst) "Comp1" (inflow of the secondary component 1) "Comp2" (inflow of the secondary component 2) "Quantity" (inflow of the main component) The structure of the simulation of the individual inflows differs only in the interconnected signals. The following figure describes an example of the structure of the diagrams at the inflow of the main component: Figure 3-18 "Quantity" diagram structure The global connector "YC_Quantity/Y1" passes the current valve position from the diagram "YC_Quantity" to the diagram "Quantity". The connector is connected to the "Flow" macro. The current flow is calculated based on the valve position and the maximum flow rate of 1000 l/h of the main component's inflow. The current flow rate is passed on to the automation system by means of the "PLCSIM Quantity_PV" I/O connector input. Furthermore, the flow rate is converted from l/h into m³/h (multiplied by 10-3 ) to make the current flow rate available through the global connector "YC_Quantity/Flow" for further calculations in other diagrams. Entry ID: , V1.0, 06/

40 3 Design and principle of operation Simulation of the fill level In the present application example, the fill level simulation is accomplished in the "Level" and "Product" diagrams. "Product" The "Product" diagram simulates a discharge. In principle, the diagram structure corresponds to an inflow. The figure below describes the structure of the "Product" diagram: Figure 3-19 "Product" diagram structure When compared to the structure of the discharge diagram, only the "Input" I/O connector is missing. Entry ID: , V1.0, 06/

41 3 Design and principle of operation "Level" The current fill level is calculated in the "Level" diagram, based on the incoming and outgoing flows. Different values, such as mass in the reactor [kg] or volume in the reactor [l] are also calculated. The figure below describes the structure of the "Level" diagram: Figure 3-20 "Level" diagram structure The diagram is divided into the following 7 areas: 1. Inflow 2. Discharge 3. Calculation of the current mass in the reactor 4. Total amount of the product for key performance 5. Calculation of the upper limit of integration 6. Conversion of mass to fill level in liters and percent 7. Sum of the current fill level and uniformly distributed noise to ± 1% Entry ID: , V1.0, 06/

42 3 Design and principle of operation The following table contains the descriptions for each area. Table 3 1 Area Description Inflow The inflow into the reactor is formed from the sum of the individual discharges. These are passed on via global connectors from the respective flow diagrams to the "Level" diagram. The current inflows are passed on as volume flow [m³/h] and then converted to mass flow [kg/h] by multiplication by the respective density and added to the total mass flow. Discharge The discharge from the reactor is passed on to the "Level" diagram via the global connector "YC_Product/Flow" as current volume flow [m³/h]. The volume flow is converted to mass flow [kg/h] by multiplying it by the density of the product. Calculation of the current mass in the reactor The outgoing mass flow is first multiplied by "-1" and then added to the sum of the incoming mass flows. The result is the current mass change in the reactor in kg/h. This is converted into kg/s with the aid of the "PerHourToPerSecond" macro. By integrating this mass flow with the time constant T = 1 second, the current mass inside the reactor is given in kg. Total product mass The outgoing mass flow is also interconnected to a further integrator to determine the total amount of product removed from the reactor. The mass flow is previously converted from kg/h to kg/s with the "PerHourToPerSecond" macro. The result is forwarded to the "Connections" diagram through the global connector "SL/SUMPRODUCT". Calculation of the upper limit of integration The upper integration limit of the integrator for the current mass corresponds to the maximum mass that can be accommodated by the reactor. It is calculated from the product of the reactor volume and the density of the product. Conversions Based on the current mass inside the reactor, the fill level can be derived in meters, and the product and fill level volume in percent. The fill level in percent is calculated from the product of the quotient of current mass inside the reactor divided by the maximum mass inside the reactor and 100. The volume is determined by multiplying the density of the product by the mass. This is then also multiplied by This gives the value in m³ and liters for the volume. Fill level with measurement noise In addition to the calculated fill level in percent, a uniformly distributed measurement noise of ± 1 percent is also added. The measurement noise can be switched via an analog value switch and is therefore optional. Entry ID: , V1.0, 06/

43 3 Design and principle of operation Global connectors The following table summarizes the global connectors of the "Level" diagram, which forwards the values to other diagrams: Table 3-2 Global connectors of the Level diagram Connector Value Diagrams "Catalyst_Flow_kg/h" "Comp1_Flow_kg/h" "Comp2_Flow_kg/h" "Quantity_Flow_kg/h" "SL/SumFlowFeed" Mass flow of the catalyst [kg/h] Mass flow of the secondary component 1 [kg/h] Mass flow of the secondary component 2 [kg/h] Mass flow of the main component [kg/h] Total mass flow of the inflows [kg/h] "Density", "Heat Capacity", "Temp_Reactor" "Density", "Heat Capacity", "Temp_Reactor" "Density", "Heat Capacity", "Temp_Reactor" "Density", "Heat Capacity", "Temp_Reactor" "Density", "Heat Capacity", "Connections" "SL/SumProduct" Total product mass [kg] "Connections" "Mass_Reactor" "Volume_Reactor" "SL/MReactorLiter" "SL/MReactorPercent" Mass of the reactor contents [kg] Volume of the reactor contents [m³] Volume of the reactor contents [l] Volume of the reactor contents [%] "Temp_Reactor" "Pressure" "Connections" "Connections" Entry ID: , V1.0, 06/

44 3 Design and principle of operation Pressure simulation In the present application example, the pressure simulation is accomplished in the "Pressure" diagram. The figure below describes the structure of the "Pressure" diagram: Figure 3-21 Pressure diagram structure The diagram is divided into the following 7 areas: 1. Inflow and discharge of inert gas 2. Current gas volume in the reactor 3. Sum of the supplied inert gas 4. Current mass of inert gas in the reactor 5. Maximum mass of inert gas in the reactor 6. Calculation of pressure 7. Reactor pressure with uniformly distributed noise of ± bar Entry ID: , V1.0, 06/

45 3 Design and principle of operation The following table contains the descriptions for each area: Table 3 3 Area Description Inflow and outflow Inflow and discharge of the inert gas are calculated as mass flow [kg/h] with the aid of the "Flow" macro. It is assumed that a maximum mass flow rate of 100 kg/h for the inert gas feed and venting is possible. Together with the current valve position of the inflow or vent valve, the current mass flow is calculated and then converted into kg/s using the "PerHourToPerSecond" macro. The mass flow resulting from the venting is additionally multiplied by "- 1", since the mass is removed from the balance space. Current gas volume It is first checked whether the reactor is completely filled with the product. If this is not the case, the current volume of the product in the reactor is used for further calculation. If the reactor is completely filled, a substitute value (reactor volume minus "0.1") is specified. This is necessary to avoid a division by "0". The current volume of gas in the reactor is obtained from the difference between the reactor volume and the current volume of the product (or the replacement value) in m³. Sum of the supplied inert gas The mass flow of the inert gas is interconnected to an integrator to determine the total amount in kg of inert gas. The time constant of the integrator is 1 second. Current mass of inert gas To determine the actual mass of the inert gas, the mass flows of the inflow and venting are added. The sum is then interconnected with an integrator. The time constant of the integrator is 1 second. The result of the integration corresponds to the current mass of inert gas in the reactor in kg. Current mass of inert gas The maximum mass of inert gas in the reactor is calculated using the ideal gas law, which is converted according to the mass. The mass of inert gas is the quotient from the product of the maximum pressure in the reactor [Pa] and the reactor volume [m³] and the product of the ideal gas constant for nitrogen and a temperature of Kelvin. The calculated value is used in the "pressure" diagram as an integration limit for the integrator. Calculation of pressure The pressure in the reactor is calculated using the ideal gas law. The pressure in the reactor corresponds to the quotient from the product of the current mass of gas in the reactor, the gas constant (nitrogen), the current temperature in the reactor and the current volume of gas in the reactor. The air pressure is then added. This gives the pressure in the reactor in Pa. This is converted into bar by multiplying it by 1*10 5. Reactor pressure with measurement noise In addition to the calculated reactor pressure in bar, a uniformly distributed measurement noise of ± 0.01 bar is also added. The measurement noise can be switched via an analog value switch and is therefore optional. Entry ID: , V1.0, 06/

46 3 Design and principle of operation Global connectors The following table summarizes the global connectors of the "Pressure" diagram, which forwards the values to other diagrams: Table 3 4 Global connectors of the "Pressure" diagram Connector Value Diagrams "SL/SumInertgas" Total amount of inert gas [kg] "Connections" "SL/PressureReactor" Reactor pressure [bar] "Connections" Simulation of temperature "Temp_Jacket" In the present application example, the temperature simulation is accomplished in the "Temp_Jacket" and "Temp_Reactor" diagrams. In the "Temp_Jacket" diagram, the temperature is calculated at the the cooling jacket output. The figure below describes the structure of the "Temp_Jacket" diagram: Figure 3-22 "Temp_Jacket" diagram structure The diagram is divided into the following 9 areas: 8. Mass flow of the heating medium 9. Temperature of the heating medium 10. Mass flow of the coolant 11. Temperature of the coolant 12. Total heat flow 13. Specific heat capacity of the medium in the cooling jacket 14. Rate of temperature change 15. Temperature of the cooling jacket output 16. Temperature of the cooling jacket output with uniformly distributed noise of ±1 C Entry ID: , V1.0, 06/

47 3 Design and principle of operation The following table contains the descriptions for each area: Table 3 5 Area Description Mass flow of the heating medium The mass flow [kg/h] of the heating medium is calculated using the "Flow" macro. It is assumed that a maximum mass flow of 100 kg/h is possible. Together with the current valve position of the control valve for the heating medium, the current mass flow is calculated and then converted into kg/s using the "PerHourToPerSecond" macro. Temperature of the heating medium In the temperature simulation of the heating medium, it is assumed that this corresponds to the position of the valve in percent. This means that if the valve is open to 50%, the temperature of the heating medium is 50 C. The temperature is then converted into Kelvin by adding to the value. Mass flow of the coolant The mass flow [kg/h] of the coolant is calculated using the Flow macro. It is assumed that a maximum mass flow of 100 kg/h is possible. In addition to the current valve position of the coolant control valve, the current mass flow is calculated and then converted to kg/s with the PerHourToPerSecond macro. Temperature of the coolant In the temperature simulation of the heating medium, it is assumed that this corresponds to the negative position of the valve in percent. This means that if the valve is open to 50%, the temperature of the coolant is -50 C. The temperature is then converted into Kelvin by adding to the value. Total heat flow The total heat flow is derived from the sum of the heat flows through the heating medium, the coolant and the heat flow produced by the heat transfer from the reactor to the cooling jacket. The heat flow of the heating medium is calculated using the "Heat_Flow1" macro. The inputs of the macro are interconnected with: current mass flow of the heating medium [kg/s] specific heat capacity of the heating medium [m²/s²*k] Temperature of the heating medium [K] Temperature of the cooling jacket output [K] The output of the macro is the heat flow of the heating medium in kg*m²/s³. The heat flow of the coolant is calculated using the "Heat_Flow1" macro. The inputs of the macro are interconnected with: current mass flow of the coolant [kg/s] specific heat capacity of the coolant [m²/s²*k] Temperature of the coolant [K] Temperature of the cooling jacket output [K] The output of the macro is the heat flow of the coolant in kg*m²/s³. The heat flow resulting from the heat transfer between the reactor and cooling jacket is calculated using the "Heat_Flow2" macro. The inputs of the macro are interconnected with: Heat transfer coefficient [kg/s³*k] Heat transfer area [m²] Reactor temperature [K] Mean cooling jacket temperature [K] The output of the macro is the heat flow in kg*m²/s³, resulting from the heat transfer between the reactor and cooling jacket. Entry ID: , V1.0, 06/

48 3 Design and principle of operation Area Global connectors Description Specific heat capacity of the medium in the cooling jacket The medium in the cooling jacket is a mixture of the heating medium and the coolant. It is simply assumed that the specific heat capacity of the medium in the cooling jacket is composed of equal parts of the specific heat capacities of both the heating medium and the coolant. Rate of temperature change The rate of temperature change in the cooling jacket is calculated with the "Rate_of_temperature_change" macro. The inputs of the macro are interconnected with: Current heat flow [kg*m²/s³] Mass of the medium in the cooling jacket [kg] (assumed to be constant) Specific heat capacity of the medium in the cooling jacket [m²/s²*k] The output of the macro is the rate of temperature change in the cooling jacket in K/s. Temperature of the cooling jacket output The current temperature in Kelvin at the cooling jacket outlet is obtained by integrating the rate of temperature change. The time constant of the integrator is 1 second. The upper integration limit is , the lower integration limit is The temperature value in Kelvin is converted to degrees Celsius by subtracting Temperature of the cooling jacket output with measurement noise In addition to the calculated temperature of the cooling jacket output in degrees Celsius, a uniformly distributed measurement noise of ± C is also added. The measurement noise can be switched via an analog value switch and is therefore optional. The following table summarizes the global connectors of the "Temp_Jacket" diagram, which forwards the values to other diagrams: Table 3 6 Global connectors of the "Temp_Jacket" diagram Connector Value Diagrams "Temp_Heat_Kelvin" "Temp_Cool_Kelvin" "SL/TempJacket" Temperature of the heating medium [K] Temperature of the coolant [K] Temperature of the cooling jacket output [ C] "Temp_Reactor" "Temp_Reactor" "Connections" Entry ID: , V1.0, 06/

49 3 Design and principle of operation "Temp_Reactor" In the "Temp_Reactor" diagram, the temperature of the reactor is calculated. The figure below describes the structure of the "Temp_Reactor" diagram: Figure 3-23 "Temp_Reactor" diagram structure The diagram is divided into the following 6 areas: 1. Properties of the inflows 2. Total heat flow 3. Rate of temperature change 4. Mean temperature in the cooling jacket 5. Temperature in the reactor 6. Temperature of the reactor with uniformly distributed noise of ±1 C The following table contains the descriptions for each area. Table 3 7 Area 1 2 Description Properties of the inflows The mass flows of the inflows from the main component, secondary components and catalyst are converted from kg/h to kg/s using the "PerHourToPerSecond" macro. Temperatures are also converted from degrees Celsius to Kelvin. Total heat flow The total heat flow is derived from the sum of the heat flows through the main component, the secondary component and the heat flow produced by the heat transfer from the reactor to the cooling jacket. The heat flow of the main component is calculated using the "Heat_Flow1" macro. The inputs of the macro are interconnected with: Current mass flow of the main component [kg/s] Specific heat capacity of the main component [m²/s²*k] Temperature of the main component [K] Temperature of the reactor [K] Entry ID: , V1.0, 06/

50 3 Design and principle of operation Area 3 Description The output of the macro is the heat flow of the main component in kg*m²/s³. The heat flow of the secondary component 1 is calculated using the "Heat_Flow1" macro. The inputs of the macro are interconnected with: Current mass flow of the secondary component 1 [kg/s] Specific heat capacity of the secondary component 1 [m²/s²*k] Temperature of the secondary component 1 [K] Temperature of the reactor [K] The output of the macro is the heat flow of the secondary component 1 in kg*m²/s³. The heat flow of the secondary component 2 is calculated using the "Heat_Flow1" macro. The inputs of the macro are interconnected with: Current mass flow of the secondary component 2 [kg/s] Specific heat capacity of the secondary component 2 [m²/s²*k] Temperature of the secondary component 2 [K] Temperature of the reactor [K] The output of the macro is the heat flow of the secondary component 2 in kg*m²/s³. The heat flow of the catalyst is calculated using the "Heat_Flow1" macro. The inputs of the macro are interconnected with: Current mass flow of the catalyst [kg/s] Specific heat capacity of the catalyst [kg*m²/s³] Temperature of the catalyst [K] Temperature of the reactor [K] The output of the macro is the heat flow of the catalyst in kg*m²/s³. The heat flow resulting from the heat transfer between the reactor and cooling jacket is calculated using the "Heat_Flow2" macro. The inputs of the macro are interconnected with: Heat transfer coefficient [kg/s³*k] Heat transfer area [m²] Mean temperature of the cooling jacket [K] Temperature of the reactor [K] The output of the macro is the heat flow in kg*m²/s³, resulting from the heat transfer between the reactor and cooling jacket. The heat flows caused by the inflows can be set with analog value switches to a fixed value. Rate of temperature change The rate of temperature change in the cooling jacket is calculated with the "Rate_of_temperature_change" macro. The inputs of the macro are interconnected with: Current heat flow [kg*m²/s³] Product weight in the reactor [kg] Specific heat capacity of the product [m²/s²*k] The output of the macro is the rate of temperature change in the reactor in K/s. 4 Mean temperature in the cooling jacket The mean temperature in the cooling jacket is calculated with the "T_Mean" macro. The inputs of the macro are interconnected with: Temperature of the heating medium [K] Temperature of the coolant [K] Temperature of the cooling jacket output [K] The macro output is the mean temperature of the cooling jacket. Entry ID: , V1.0, 06/

51 3 Design and principle of operation Area 5 6 Description Temperature in the reactor The current temperature in Kelvin in the reactor is obtained by integrating the rate of temperature change. The time constant of the integrator is 1 second. The upper integration limit is , the lower integration limit is The temperature value in Kelvin is converted to degrees Celsius by subtracting Temperature of the reactor with measurement noise In addition to the calculated temperature in the reactor in degrees Celsius, a uniformly distributed measurement noise of ± C is also added. The measurement noise can be switched via an analog value switch and is therefore optional. Global connectors The following table summarizes the global connectors of the "Temp_Reactor" diagram, which forwards the values to other diagrams: Table 3 8 Global connectors of the "Temp_Reactor" diagram "Temp_Mean" "Temp_Reactor" Connector Value Diagrams "SL/TempReactor" Mean temperature of the cooling jacket [K] Temperature of the cooling jacket output [K] Temperature of the cooling jacket output [K] "Temp_Jacket" "Heat Capacity" "Pressure" "Temp_Jacket" "Connections" Entry ID: , V1.0, 06/

52 4 Launching the application example 4 Launching the application example 4.1 Preparation The following instructions describe putting the SIMIT application example into service: Note The preparations that are to be performed on the corresponding PCS 7 project can be found in chapter 5.1 "Preparation" of the documentation for the "Stirred tank reactor" PCS 7 Unit Template. Table 4 1 No. Action 1. Copy the file "xyz_stirredtankreactor.simarc" into any folder on the configuration PC and and then open SIMIT. 2. Select the menu item "Dearchive project". 3. Select the archived project in the "Archive name" field and click "Open" to confirm the dialog. 4. In the field "destination folder", select the path where you want to dearchive the SIMIT project and click "Open" to confirm the dialog. 5. Now click on the "Dearchive" button. 6. Change from the "Portal view" to the "Project view" 4.2 Commissioning The following instructions describe how the Application example is initialized: Note The steps that have to be taken on the PCS 7 project before commissioning can be found in chapter 5.1 "Preparation" of the documentation for the "Stirred tank reactor" PCS 7 Unit Template. The following is required for commissioning: The simulation of the PCS 7 program (S7-PLCSIM) and the WinCC Runtime are in the "Run" state SIMIT is running SIMIT project is dearchived VIew is in project view Entry ID: , V1.0, 06/

53 4 Launching the application example Starting the simulation model To start the simulation, proceed according to the following instructions: Table 4 2 No. Action 7. Start the simulation "Simulation > Start". 8. In the "Scripting" folder of the project window, right-click on the "Initialize" script and select the "Open" menu point. 9. Right-click once again on the "Initialize" script and select the "Start" menu point. 10. Wait until flashing symbol for the script execution no longer appears in the status bar. 11. Change to the WinCC runtime: Acknowledge the alert messages Check if the system has settled (controller setpoints correspond to the actual values) Entry ID: , V1.0, 06/

54 5 Operating the application 5 Operating the application 5.1 Overview The parameters that have an influence on the process model can be changed from the SIMIT process picture (diagram "Standard_Chart") or by using scripts. The impacts of the change can be monitored at the PID controllers of the WinCC runtime. The following scenarios are possible: Scenario A: Change the temperature of the inflows Scenario B: Change the material properties of an inflow Scenario C: Change via the visualization interface The size changes made in the scenarios act as disturbance variables in one or more controllers. 5.2 Scenario A: Change of temperature of the inflows Description During a continuous manufacturing process, it may happen that the temperatures of the inflows change. However, the necessary temperature in the reactor must be kept. In this scenario, the temperatures of the inflows are changed using the "Temp_Change_Feed" script. The temperatures for all inflows are changed from 50 C to 95 C. The desired value for the temperature in the reactor remains at 50 C. As a result of which, the manipulated variable output from the controller is changed and the controller receives new setpoints for the cooling jacket temperature. Entry ID: , V1.0, 06/

55 5 Operating the application Table 5 1 No. Action 1. In the "Scripting" folder of the project window, right-click on the "Temp_Change_Feed" script and select the "Open" menu point. 2. Switch to the runtime window of WinCC. 3. Click on the block icon of "TIC_Jacket" and click on the trend icon in the menu bar of the faceplate. 4. Click on the block icon of "TIC_Reactor" and click on the trend icon in the menu bar of the faceplate, in order to also open its trend window. Arrange the trend windows clearly. 5. Switch back to SIMIT. 6. In the "Scripting" folder of the project window, right-click on the "Temp_Change_Feed" script and select the "Start" menu point. 7. Change to the WinCC runtime. 8. Wait until the system has settled again after changing the inflow temperature and click on "Start/Stop" to evaluate the controller result. Entry ID: , V1.0, 06/

56 5 Operating the application Evaluation The following figure shows the trend curves of the PID controllers: Figure Temperature change by around 0.25 C 2 Setpoint change by around 3% 3 Temperature change by around 0.25 C 4 Setpoint change by around 3 % Entry ID: , V1.0, 06/

57 5 Operating the application The small temperature change in the reactor (1) is attributed to the following factors: The temperature of the inflow rises by 45 C. The change in temperature is detected by the controller as a disturbance variable and corrected. A setpoint value change of about 3% is required (2) to maintain the setpoint temperature. The setpoint value of the temperature regulator for the reactor is the setpoint value for the temperature in the cooling jacket. The temperature in the cooling jacket is decreased by about 2.5 C (3) to maintain the setpoint temperature in the reactor. The manipulated variable is changed by about 3% to decrease the temperature in the cooling jacket. Entry ID: , V1.0, 06/

58 5 Operating the application 5.3 Scenario B: Change the material properties of an inflow During a continuous manufacturing process, it may happen that the material properties of an inflow change (other material). The controllers need to respond in such a way that the setpoints are met. In this scenario, the properties of density, temperature, specific heat capacity and temperature coefficient of the inflow of the main component are changed using the "Change_Properties_Quantity" script. Table 5 2 No. Action 1. In the "Scripting" folder of the project window, right-click on the "Initialize" script and select the "Start" menu point to recreate the starting point. Wait until the system is stable again. 2. In the "Scripting" folder of the project window, right-click on the "Change_Properties_Quantity" script and select the "Open" menu point. 3. Switch to the runtime window of WinCC. 4. Click on the block icon of "LIC_Level" and click on the trend icon in the menu bar of the faceplate, in order to also open its trend window. 5. Switch back to SIMIT. 6. In the "Scripting" folder of the project window, right-click on the "Change_Properties_Quantity" script and select the menu point "Start". 7. Switch to the WinCC runtime. 8. Wait until the system has settled again after changing the material properties and click on "Start/Stop" to evaluate the controller result. Entry ID: , V1.0, 06/

59 5 Operating the application Evaluation The following figure shows the trend curve of the PID controller: Figure Change of fill level by around Change of setpoint value by 2 3 After starting the script, the fill level jumps by 8% (1). This is because the model calculates how much material in kg fits into the reactor. This is calculated using the reactor volume and the density of the material in the reactor. The density of the material is calculated depending on the densities of the inflows in the "Density" diagram (see chapter 3.1 "Project structure"). By changing the density of the inflow of the main component, the material in the reactor is changed at the same time which also changes the maximum mass that can be contained in the reactor. The percentage of fill level is calculated from the current mass in the reactor and the maximum mass. As only the maximum mass in the reactor is changed at the time of the change in the main component's density, while the actual mass in the reactor remains the same, the fill level jumps up in percent. The controller responds to this jump by changing the setpoint value from 61% to 100% (2). Then the manipulated variable is set in such a way that the setpoint value of the fill level is kept. Following the change, the setpoint value is 52% (3). Other changes in the properties have little influence on the behavior of the model. Entry ID: , V1.0, 06/

60 5 Operating the application 5.4 Scenario C: Change via the visualization interface Description In this scenario, you change the parameters of the model via the visualization interface. The changes that arise from it, can be monitored in the visualization interface and in WinCC. An example of a measurement noise is simulated in this scenario. Table 5 3 No. 1. Open the "Standard" diagram. Action 2. Activate the measurement noise for pressure, fill level, reactor temperature and cooling jacket temperature Monitor the values of the temperatures. They now only vary by ± 1 C. 1 Entry ID: , V1.0, 06/

61 5 Operating the application No. Action 4. Switch to the WinCC Runtime and monitor even here the process values The trend curve for the temperature regulator of the reactor without (1) and (2) measurement noise, is shown on the screen as an example. One can easily recognize that with the set controller parameters the measurement noise has direct influence on the manipulated variable. 5. The visualization interface makes it possible to change the model between standard component and user-defined component type. Entry ID: , V1.0, 06/