Intelligent Agents as Communications between Worlds

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Logan Barrett
5 years ago
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1 White Paper Intelligent Agents as Communications between Worlds The idea of worldwide, intelligent networking is daily common practice; s and web services allow the rapid exchange of data in the worldwide web. The new generation of cyber-physical systems will change the world of production. Under the heading "Industry 4.0", communication will shift from the supraordinate software to dedicated, embedded intelligence of individual components. Flexible, intelligent interface communicators will be used here. With current technological developments, online monitoring and control of processes, machines and sensor systems is possible. In the field of production we encounter a multitude of control interfaces with different ways of working. Computers that perform their task as controllers, as programmable logic controllers (PLC) or as industrial PCs (IPC) act as control units. Backwards compatibility of the information works only in combination with the relevant software. This software must be capable of understanding the various languages of the controllers, translating it into usable data protocols and to take care of the handshake. What is an agent? An agent is an autonomous system that acts independently to achieve a pre-set goal. Generally viewed, agents are used as an interface between different data processing systems. Automated production is a specific area of application. Machines generate production data that has to be evaluated, monitored and archived and they request information and parameters on the basis of which the machine can be configured and controlled. For this, production data must be continuously transferred from the machine to the production database and, on the request of the machine, data must be transferred from the production database to the machine. The job of the agent is to create a machine production database interface, without which such a data exchange would not be possible. Page 1 of 10

2 Data Processing System e. g. machine Data Processing System e. g. production database Interface Interface Figure 1-1 Agent, abstract view Host System The agent is software that runs on a host system. The host system can be any computer, e.g. the control computer of a machine, a dedicated computer made available to the machine or an existing computer that is shared (e.g. a line server). Dedicated Machine Machine Machine Computer Network Database Diagnosis Software Application Server Figure 1-2 Agent host systems Page 2 of 10

3 Choosing the Host System Various aspects need to be considered when choosing a host system. Requirements, cost and risks are directly connected. No general recommendation for one of the variants can be made. Instead, you should examine in each individual case which variant is the most sensible for the given tasks. The overview below is designed to help. Machine control computer Dedicated computer + No additional costs for hardware + Direct access to the machine's output data (possibly the only way to access the data) without delays through a network or bus system. - System requirements of the transfer agent may require the installation of software, drivers and services on an external system + System environment of the machine computer does not have to be adapted to the agent system requirements + Known and tested environment, no problems with installation and operation (plug and play) - Additional costs for hardware, maintenance Remote host system + System environment of the machine computer does not have to be adapted to the agent system requirements + No additional costs for hardware + Agents can be centrally configured, no physical access to each individual machine necessary - System requirements of the agent may require the installation of software, drivers and services on an external system Page 3 of 10

4 Internal Data Processing The agent should process data in four modular stages, see Figure 0-1. select transform Data source Destination Figure 0-1 Data processing Data d Raw data arrive at the agent from a data source via a configured interface. Select data The agent extracts data from the raw data. For this, the data format and the data fields to be extracted have to be configured. Transform data The agent formats the data to be ted, e.g. it creates SQL statements to transfer data to the tables and fields of a database model. For this, the data format and the formatting to be carried out have to be configured. Transmit data Data is ted to a destination via a configured interface of the agent. Page 4 of 10

5 The modular structure of an agent enables the logical splitting of data processing into two separate, asynchronous processes, see Figure 0-2. The data is initially d by the data source. To reduce the data volume, the relevant data is selected from the raw data d. The remaining relevant data is transferred to an interim store (e.g. file, database). Asynchronously and separately from this, new data is continuously read out from the interim store, formatted for the target data model and then transferred to the destination. Both processes are performed by the partial modules of the agent software. select transform Data source Interim store Destination Figure 0-2 Logical splitting of the internal data processing stages The logical splitting of the agent modules gives the necessary flexibility to do justice to the different requirements of data transfer, as the following section will show. Data Transfer and Deployment Scenarios Depending on the task, the agent makes different demands of the data transfer, e.g. with respect to performance, data volumes, bidirectional data transmission and data synchronisation. This has direct consequences for the agent's possible deployment scenarios. The agent should be used so that the machines to be connected are influenced as little as possible. In particular, disadvantages such as loading new version or updates on the machine computers (never change a running system) administration and maintenance work on the machine computers increased pressure on the resources of machine computers should be reduced to a minimum. The aim is to distribute the tasks "Get data from the machine" "Select data" Transform data" "Import data to the production database" optimally on the existing computer structure. Page 5 of 10

6 Possible deployment scenarios and the resultant advantages and disadvantages are explained below. Direct Data Transfer from the Machine to the Production Database In direct data transfer from the machine to the production database, the agent directly accesses the production database. The data transfer is done in a transaction, see Figure 0-3. select transform Machine Production database Figure 0-3 Direct data transfer, machine > production database Data transfer from the production database to the machine is also in a transaction, in which the agent directly accesses the production database, see Figure 0-4. transform select Machine Production database Figure 0-4 Direct data transfer, production database > machine Page 6 of 10

7 Advantages + Data synchronisation, i.e. database queries from the machine can rely on the fact that all of the relevant production data is present. + Highest possible performance of the data transfer (the direct way is the shortest) Disadvantages - Rigid coupling of machine and production database - The agent's host system bears the full load of the data transfer. (If the host system is also the machine computer, its performance can hardly be changed subsequently, or maybe not at all. Thus as a loss of performance scalability) - All agents need knowledge about the data model of the production database. This synonymous with increased configuration effort, both for initial installation and for subsequent modifications and expansions of the data model. Indirect Data Transfer from the Machine to the Production Database In the indirect data transfer from the machine to the production database the data transfer takes place in two stages. In the first stage, data is d from the machine, selected and written into a transfer database. In the second stage, data is transferred from the transfer database to the production database. The two stages are separate from each other, see Figure 0-5. select transform Machine Transfer database Production database Figure 0-5 Indirect data transfer, machine > production database Page 7 of 10

8 Data transfer from the production database to the machine takes place by avoiding the transfer database, in a transaction, in which the agent directly accesses the production database, see Figure 0-6. transfer select Machine Production database Figure 0-6 Direct data transfer, production database > machine Advantages + Clear, logical decoupling of machine access and access to the production data model when transferring data to the production database. + Transformation and import to the production database can be moved to the most suitable computer (performance, disk capacity). In the simplest case, only text files are passed on by the machine computer. The more complex process of transforming and loading to the production database takes place on a host system with scalable performance. Disadvantages - Data synchronisation cannot be guaranteed, i.e. database queries from the machines cannot rely on all of the relevant production data already being present. - The host system that takes care of the data import from the transfer database to the production database is severely loaded since the data from all machines has to be recorded centrally and passed on. + Modifications to the production database or the data model do not automatically lead to software being loaded onto the machine computer. Page 8 of 10

9 Requirements and Preconditions There are the following requirements and preconditions for the agent: Functionality Extensive repertoire of interfaces, formats and protocols Support for industrial standards on system effectiveness, e.g. SEMI, E10, VDI 3423, IPC. The aim is the simple and fast configurability of the agent with the help of prefabricated machine and database templates Configuration should be possible without programming knowledge Data buffering in a buffer memory in the event of a failure of the connections to destinations to prevent data loss Performance profiling to be able to determine the performance of the system and recognise bottlenecks Configurable alarms, that are triggered when the connections to the destinations are interrupted, for example. Logging of data transfers, faults, warnings, notes, etc. Structure Flexible configuration of the interfaces New interface types and data formats must be modularly expandable and flexibly parameterisable Event-controlled data processing for minimum loading of the host system and the fastest possible processing of new data Multi-threading to avoid data loss if data temporarily cannot be processed quickly enough and for better utilisation of the multi CPU systems Modular structure to be able to expand the application flexibly Page 9 of 10

10 Embedded Agents An embedded agent is an agent that can run on embedded systems. Just like the "normal" agent, the embedded agent is capable of translating the data of an automation system with various machine and control languages into a uniform format and transfer it to a destination system. The advantages of the embedded agents in comparison to the normal agents are mainly savings through fewer hardware procurements. Normally, a Windows PC is needed to execute the agents. However, if it runs directly on the embedded systems of the automation systems, this is no longer necessary and the data can be transferred via communication channels at a few points to the diagnosis software. Central Aspects Platform-independent programming Possible operation systems o Controls o Field bus master o Field bus modules o Intelligent sensors Future productions and products to be manufactured can be identified with their own unique production parameters and process controlling elements. The integration of agents and embedded agents opens up new perspectives for the manufacturing process, such as components with pre-installed agents do not have to be configured, but only parameterised. Networking is thus a partial process of installation and offers new areas of deployment. Consistent transparency and communication of all of the units involved in the process. Contact to ifm datalink: ifm datalink gmbh Benno-Strauß-Str Fürth / info@ifm-datalink.com Page 10 of 10

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