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WP4: Process Control Testbed. Universidad Politécnica de Madrid. WP4 / M. Rodríguez / Lund 16 September 2003. Outline. Overview Non HRTP Implementation HRTP Implementation Conclusions. Overview. Overview & previous work. Objective.
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WP4: Process Control Testbed Universidad Politécnica de Madrid WP4 / M. Rodríguez / Lund 16 September 2003
Outline • Overview • Non HRTP Implementation • HRTP Implementation • Conclusions
Overview & previous work Objective The main objective of the distributed process control testbed is to identify requirements for distributed control systems and perform experiments in conditions of systems heterogeneity and legacy integration. Experiments will be done using conventional IIOP and the new real-time protocol.
Overview & previous work Previous Work • PCT Requirements specification • PCT Design • PCT Procurement
Main Activities • Non HRT Implementation • Non HRT Testing • PCT Documentation
Non HRTP Implementation Introduction For every experiment the following pattern is presented: • Purpose & experiment definition • Hardware implementation • Software implementation • Testing
Non HRTP Implementation Ethernet Control Loop To demonstrate the use of CORBA components for the implementation of control loops. A simple regulatory control loop with three components: 1. Sensor 2. Actuator 3. Controller built as independent nodes connected through the Ethernet. Also there are two additional nodes: 1. HMI 2. Historical Database
Non HRTP Implementation HW Implementation
Non HRTP Implementation SW Implementation
Non HRTP Implementation Testing The experiment has been conducted in two stages: First stage: Start the process only (without control). The pumps were manually controlled and the sensor values were monitored. Second stage: Run the process with the control loop closed (automatic mode). In order to test the capacity of CORBA the time cycle of the loop was reduced decrementing the time between controller calls to the pH sensor and actuator. All the PCs were synchronized using NTP.
Non HRTP Implementation Integration of legacy systems The purpose of this experiment is to demonstrate the integration of legacy systems in a CCS. A commercial Honeywell TPS distributed control system is wrapped to become another CORBA node in the system
Non HRTP Implementation HW Implementation
Non HRTP Implementation SW Implementation
Non HRTP Implementation Testing 1. Limitations of the connection 2. Use of the TPS controller with CCS sensor and actuator 3. Use of CCS controller with TPS sensor and actuator 4. Use of TPS sensor with CCS controller and actuator
Non HRTP Implementation Interaction of simulation & control The purpose of this experiment is to test and identify requirements for the use of simulation objects on a CCS. A simulation node shall be introduced on a Ethernet network with the CCS control loop configuration. This node should interact in several ways with the control agents
Non HRTP Implementation HW Implementation
Non HRTP Implementation SW Implementation
Non HRTP Implementation Testing Operators training (interaction between the simulation and the HMI nodes). In this case the process and the control system are simulated. The HMI sends and receives data from the simulator. The time of execution of the simulation is slowed down to resemble the actual time of the process. Hardware in the loop (interaction between the simulation and the actual controller). In this test the system simulated is the process plant with the sensors and actuators. The pH controller is left out of the model. The real pH controller implemented in a separate CORBA node is used to control the simulated plant.
Non HRTP Implementation Intensive data traffic The purpose of this experiment is to check capacity limits of the system when the number of control elements increases. During the test, the number of instances of simulated sensors and actuators on their respective nodes is increased progressively, as well as the corresponding number of controllers
Non HRTP Implementation HW Implementation
Non HRTP Implementation SW Implementation
Non HRTP Implementation Testing • Every node with single functionality (all the virtual sensors are in a PC, all the actuators in another PC...) • Every node has multiple functionality (In every node there are virtual sensors, actuators and controllers – not sending messages between them) • Heavy network loads (by transferring huge amount of data between the network PCs).
Non HRTP Implementation Concurrency access The purpose of this experiment is to identify concurrency issues in CCS. In this test multiple nodes try to access concurrently to a sensor node. As in the previous test, the number of client instances increases progressively.
Non HRTP Implementation HW Implementation
Non HRTP Implementation Testing Only some testing with multiple virtual objects(regulators) accesing a single node (sensor) has been conducted.
HRTP Implementation TTP/C Control Loop To demonstrate the use of CORBA components for the implementation of control loops. A simple regulatory control loop with three components: 1. Sensor 2. Actuator 3. Controller built as independent nodes connected through the TTP/C network. Also there are two additional nodes: 1. HMI 2. Historical Database
HRTP Implementation HW Implementation
HRTP Implementation Asynchronous event management To test the ability of CCS for implementing sequence of events register functionality. This is a measure of the accomplishment of the timing properties required by a distributed real-time control A sequence of asynchronous events occurring in different nodes is generated in a short period of time. This events are registered in a central database with their time-stamps.
HRTP Implementation HW Implementation
HRTP Implementation Network bridging To identify requirements and limits for the use of several (possibly heterogeneous) segments in a CCS network. Two CCS network segments shall be communicated through a bridge.
HRTP Implementation HW Implementation
Conclusions • There haven’t been major problems in integrating the control loop elements. CORBA is an alternative for process control systems not only where OPC operates but even at lower levels (field level) • Although existing DCS may be integrated under CORBA there are a lot of functionalities that cannot be accessed due to the lack of openness of the DCS. • Simulator integration have been easy as ABACUSSII is provided as a library and only an interface has been to be added. • Process control systems cannot sacrifice flexibility for predictability.
Work pending • More experiments in Non HRTP implementation (mainly concurrent access) • Complete Software development of HRTP implementation • Perform HRTP tests • Complete Documentation and evaluation of the PCT.