industrial automation systems can meet ever increasing demands.
But the architecture and the basic principles remain the same, so it is important to understand the automation architecture well before starting the project. These architectures provide a methodology and standardization so that the thousands of elements that make up a plant or system can work together. In this article, I will walk you through what an automation architecture is by providing the areas of development that the industry will bring in the future.
Structure of automated systems
Level 0: The ground or “functional parts” is a set of sub-components which perform physical functions (displacement, light emission, etc.), measure physical quantities (temperature, humidity, luminosity, etc.) and explain to the part ordered. It is composed of electric, pneumatic, hydraulic and other actuators, such as jacks, electric motors, etc.
- Effector: terminal equipment (cutting tools, pumps, welding heads, etc.) which act directly on the material to increase its added value;
- Actuator: a component responsible for converting energy to adapt it to the needs of the parts in operation; then, this energy is consumed by the effectors (motors, cylinders, electromagnets, heating resistors, etc.);
- Pre-actuator: Responsible for the following elements: -adapting the low level of energy available at the P.C. output to the needs of the P.O. distribution or modulation of the energy delivered to the actuator (contactor, distributor, variable speed drive, etc.).
- The sensor is responsible for all the functions of the data acquisition chain (cylinder limit switch, position detector, temperature sensor, etc.)
Level 1: also called “control part”, it is made up of one or more controllers who coordinate a series of actions on the operational part in order to obtain this additional value. These controllers can be programmable logic controllers, microcontrollers or industrial PCs.
Level 2: Monitoring or Human-Machine Interface: To control or monitor industrial installations, a human-machine interface (HMI) is used. The scope of the HMI can range from the basic solution of installing buttons and indicators on the console to 3D or augmented reality control interfaces. Most HMIs are touch screens or industrial PCs.
In any automation system, these three elements always exist, but the limits between them are not always obvious.
These are three levels with different safety and complexity requirements: the closer the system is to the machine, the simpler and more robust they are. This architecture is very important to maintain the normal operation and the safety of the installation.
But in Factory 4.0 all of these mixes and the top and bottom layers are integrated together, for example with IOT sensors and / or control components and HMI components (via servers embedded in objects). Therefore, a single object can have multiple levels. However, if we break down its architecture, we will find these different levels.
This nested architecture creates complexity at the object level, and they will have to follow the strictest level of security and high level connectivity.
Control-Command Systems (DCS)
The control equipment of the SNCC (Digital Control System (DCS)) is an automated network solution, which is a repetition of what we just saw.
Different from the centralized control system based on an industrial programmable logic controller, the centralized control system comprises a central controller which manages all the control-command functions of the system, while the DCS is composed of several modular controllers, which control the sub -system or control unit.
SNCC adds to the two previously seen levels:
Level 3 – Production Control: Control the workflow and recipes to achieve the desired end product. Archiving and optimization of the production process. It is executed by a production control software (in American English Manufacturing Execution System or MES), which can collect in real time production data from factories or workshops and analyze this data for traceability, quality control, monitoring of production, planning and preventive and therapeutic maintenance.
Level 4 – Central Planning: Establish basic plant planning, production, material use, delivery and transportation. Determine the inventory level. This collection is generally implemented by an integrated management software package or ERP (English: Enterprise Resource Planning or ERP). The software package can manage all business processes by integrating all business functions, including human resource management, accounting and financial management, decision support, sales, distribution, purchasing and electronic commerce.
Level 2-HMI / SCADA: Yes, I introduced level 2, but the meaning here is slightly different, it is called SCADA, which means supervisory control and data acquisition (industrial supervision system, which manages a large number of measurements and operations) control device). Any application that receives operating data from the system to control and optimize the system is a SCADA application. SCADA is typically supplied as software combined with hardware components such as Industrial Programmable Logic Controllers (PLCs) and Remote Terminal Units (RTUs).
Data collection begins with programmable logic controllers and RTUs, which communicate with equipment in the production center, such as plant machines and sensors. Then the data collected from the equipment is sent to the next layer, for example to the control room, the operator can use the human machine interface (HMI) to monitor the PLC and RTU control. The HMI is an important part of the SCADA system. These are the screens used by the operator to communicate with the SCADA system.
As shown in the figure, the DCS architecture greatly increases the number of connections, control devices, buses, protocols, and software layers. It’s complicated, each manufacturer has its own internal agreements, which are not always interoperable. This complexity, in particular the proprietary elements, hinders the development of Industry 4.0. The specification, open source, and open hardware plans attempt to address this issue, but all issues must be resolved and resolved before the appropriate level of security is truly available.