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Green energy integrates renewable electricity from solar, wind, and hydro into smart grids using power electronics, advanced inverters, energy storage, and grid automation to enhance reliability, power quality, and low-carbon transmission.

What Is Green Energy?

Green energy is renewable electricity from solar, wind, and hydro, using power electronics, smart grids, and storage.

✅ Power electronics and inverters convert PV DC to grid-synchronous AC.

✅ Smart grids manage variable renewables with SCADA, EMS, and demand response.

✅ Energy storage and microgrids enhance reliability, power quality, and resilience

Green energy, often synonymous with renewable energy, has gained significant attention in recent years as the world seeks to reduce its reliance on fossil fuels, minimize environmental damage, and promote a more sustainable future. This shift towards clean energy resources helps reduce greenhouse gases and air pollutants and plays a vital role in conserving non-renewable resources and promoting efficiency.

There are several green energy sources, each with unique benefits and challenges. Solar energy, one of the most popular renewable sources, harnesses the sun's energy to generate electricity. Solar panels, commonly installed on rooftops or in solar farms, convert sunlight into electricity for homes and businesses. As solar technology advances, solar system installation costs have dropped significantly, making it more accessible to individuals and communities alike. For homeowners, adopting comprehensive strategies is easier when using resources like energy management frameworks that track consumption and optimize production.

Wind energy, another widely recognized green energy source, is generated by converting the kinetic energy of wind into electricity using wind turbines. Large wind farms can produce significant energy, often enough to power entire communities or cities. However, wind power's effectiveness depends on the location and weather conditions, as wind speeds must be sufficient to generate electricity consistently. To mitigate variability, utilities often integrate energy management systems to balance wind output with demand forecasts.

Hydropower, one of the oldest renewable green energy sources, utilizes the movement of water to generate electricity. Dams and hydroelectric power stations convert the potential energy of water stored at a height into electricity, providing a stable and reliable source of energy. However, the construction of dams can lead to environmental concerns, such as habitat disruption and changes to local ecosystems. In facilities adjacent to dams, building energy management systems can tune loads to align with scheduled releases for greater efficiency.

Biomass energy is derived from organic materials, such as plants and animal waste, which can be burned directly for heat or converted into biofuels, such as ethanol and biodiesel. This form of green energy can help reduce waste and greenhouse gas emissions. However, the large-scale production of biomass crops can compete with food production and lead to deforestation. Modern plants deploy energy management controls to maintain combustion efficiency and emissions performance across feedstock variations.

Geothermal green energy taps into the Earth's natural heat by capturing steam or hot water from underground reservoirs to generate electricity. This clean energy source has a minimal environmental impact, but its availability is limited to areas with specific geological conditions. In buildings served by district geothermal, integrating building automation enables coordinated HVAC setpoints and thermal storage strategies.

Green energy offers numerous environmental benefits, such as reducing greenhouse gas emissions, air pollution, and dependence on finite energy resources like coal, oil, and natural gas. By transitioning to renewable green energy sources, we can significantly reduce our carbon footprint and mitigate the effects of climate change. Additionally, green energy technologies can create new job opportunities and stimulate economic growth.

However, there are also some drawbacks to green energy sources. For example, intermittency issues can arise with solar and wind power, depending on weather conditions. Moreover, the initial investment for installing renewable energy systems can be high, although costs have decreased recently.

Individuals can contribute to the growth of green energy by installing solar panels in their homes, using energy-efficient appliances, and supporting policies that encourage the adoption of renewable energy sources. The cost of switching to green energy varies depending on the technology, location, and government incentives available.

Emerging trends in green energy technology include advancements in energy storage solutions, such as batteries and hydrogen storage, which can help address intermittency issues. Furthermore, innovations in smart grids and microgrids allow for better integration and management of renewable sources. These improvements are complemented by advanced energy management analytics that forecast loads and orchestrate distributed assets.

Government policies play a critical role in supporting the adoption of green energy. For example, incentive programs, tax credits, and subsidies can help lower the cost of renewable power installations, making them more accessible to consumers. Additionally, regulations and targets for reducing greenhouse gas emissions and increasing the use of renewable sources can drive further investment in green energy technologies. Organizations can accelerate adoption by instituting a formal energy management program that aligns incentives, metering, and continuous commissioning efforts.

Embracing green energy sources is crucial for building a sustainable and cleaner future. By understanding the different types of green energy and their environmental benefits, individuals and governments can make informed decisions to promote adopting green energy solutions.

As the United States and other countries worldwide continue to invest in renewable technologies, the production landscape is rapidly changing. This transition to green energy sources is essential to reducing our reliance on fossil fuels, minimizing the environmental impacts of energy production, and ensuring a sustainable future for generations to come.

Increasing public awareness and education is one way to promote green energy further. By informing citizens of the benefits and potential drawbacks of different renewable sources, we can foster a more informed and engaged public, encouraging individuals to make greener choices in their daily lives.

Community-based green energy renewable projects can also help facilitate the widespread adoption of green energy. These projects, such as community solar gardens or small-scale wind farms, allow individuals who may need more resources or space to install their renewable systems to benefit from clean energy production. In addition, by pooling resources and sharing the benefits, communities can work together to create a more sustainable future.

Advancements in green energy technologies will also play a significant role in increasing the adoption of renewable sources. As researchers and engineers continue to develop more efficient and affordable technologies, the barriers to entry for green energy will continue to decrease. In addition, innovations in materials science, such as the development of more efficient solar cells or improvements in wind turbine design, can lead to significant gains in the performance of renewable systems.

Finally, international cooperation and collaboration will be essential in advancing green energy on a global scale. Climate change and environmental degradation do not respect national borders; thus, a united effort is necessary to combat these challenges. By sharing knowledge, resources, and technology, countries can work together to promote the adoption of green energy and build a more sustainable future for all.

Green energy is an essential component of a sustainable, environmentally responsible future. Investing in renewable technologies, supporting government policies, and engaging in individual and community-based efforts can help drive the adoption of green energy sources and ensure a cleaner, healthier world for future generations. With continued innovation, increased public awareness, and international collaboration, the promise of a green energy revolution becomes more attainable each day.

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Advanced energy management integrates smart grid analytics, demand response, and SCADA/IoT sensors to optimize loads, enable peak shaving, enhance power quality, and coordinate renewables, storage, and microgrids for efficient, resilient electrical systems.

What Is Advanced Energy Management?

A control-and-analytics approach to optimize electrical loads, integrate renewables and storage, and improve reliability.

✅ Load forecasting and demand response reduce peaks and costs.

✅ SCADA, IoT, and EMS enable real-time monitoring and control.

✅ Optimizes power quality, peak shaving, and asset utilization.

Advanced energy management systems involve control systems and processes. Control systems can be as simple as a residential thermostat, to very complex computer controlled systems for multiple buildings, to industrial process control. Their diligence and repeatability can also serve to maintain the savings of project improvements for years, further justifying their existence by providing economic return to the customer. Advanced energy management systems include control technology and control mode categories, basic input and output instrumentation, and the practical need to temper “things possible” with the skill level of the operators who will inherit it. The importance of advanced energy management system controllability and user-friendliness as primary design parameters will be stressed. Industry overviews of energy management systems highlight common architectures and integration paths useful during early design.

The following is a very important first statement before any discussion about control hardware: “The type of advanced energy management systems hardware used in optimization is less important than the understanding of the process and of the control concepts that are to be implemented.” The main goal should be to become clear about the process fundamentals and what should happen—then the parts and pieces are just details. This discussion of different available hardware types is a familiar but sometimes laborious and dull part of any controls text. Remember that automatic controls are really nothing more than machines that do for us what we would do ourselves if we had nothing better to do; they do work for us like any other tool, and they are only as clever as the people who craft them. As a complement, primers on energy management controls summarize control modes and device families that support these concepts.

The field of automatic control in advanced energy management systems is similar in that we continually adjust some device to cause a particular measured variable to remain at a desired state. In facilities practice, deploying a building automation system provides the supervisory layer that implements such setpoint maintenance and scheduling.

Examples:

• The need to throttle heating and cooling equipment sized for maximum load that is effectively over-sized at part load conditions. Within building energy management systems these strategies are automated through reset logic and variable speed control for stable part-load operation.

• Varying occupancy, and systems attendant to the occupants (lighting, ventilation). Guides on energy management emphasize occupancy-based control sequences that tie lighting and ventilation to real-time demand.

• Varying product throughput rate through manufacturing facilities. Establishing an enterprise energy management program helps align throughput-driven process controls with measurable performance targets.

• Varying demands, and the need to maintain level or full state for water or fuel reservoirs, feed or coal bins, etc.

• Coordination: Organizing or sequencing multiple processes in a logical and efficient manner is an important aspect of automatic control applications.

• Automation: Human beings can make very good manual controllers because we can think on our feet and consider many variables together, but most control tasks are repetitive and suitable for mechanization. Introductory references explaining what building automation is clarify how routine tasks are delegated to algorithms while operators focus on exceptions.

Automatic operation allows people to provide oversight of advanced energy management system operations and more effectively utilize their time.

• Consistency: Manual control by people can be effective, although we are not all that repeatable and are sometimes forgetful. Using machinery for automatic control adds the improvement of consistent, repeatable operations. The repeatability and consistency feature of automatic control is very important in manufacturing.

• Conservation: Supplemental enhancement control routines can be incorporated to reduce energy use while still maintaining good control. It is important to note that control systems do not necessarily reduce energy consumption unless specifically applied and designed for that purpose.

Advanced energy management automatic controls are useful for basic regulation and quality control of processes and environments. They can also be leveraged for energy savings through optimization. Properly applied, these energy management systems are reliable and cost effective.

From: Energy Management Handbook, 7th Edition, The Fairmont Press

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Energy Management Systems (EMS) enhance energy efficiency, reduce costs, and promote sustainability by monitoring, controlling, and analyzing energy use in buildings, enabling smarter resource allocation and a reduction in carbon footprint.

What are Energy Management Systems?

Energy Management Systems (EMS) are integrated platforms that monitor, control, and optimize energy consumption in facilities to enhance efficiency, promote sustainability, and achieve cost savings.

✅ Monitor and control energy use in real time

✅ Enhance efficiency, sustainability, and cost reduction

✅ Support compliance, reporting, and renewable integration

Energy management systems transform how we manage and consume electricity in industrial, commercial, and institutional power systems. By incorporating energy efficiency, building automation, smart grid technology, demand response, power monitoring, conservation, HVAC control, power optimization, renewable energy integration, and analytics, EMS offer a comprehensive EM for a more sustainable future.

By adopting Energy Management Systems, organizations can effectively manage consumption across their facilities, tracking energy usage in real-time to uncover opportunities for energy savings. This not only lowers operational costs but also reduces carbon emissions, supporting both financial performance and environmental responsibility.

Key Components of EMS

At the core of EMS systems are key components that work together to improve efficiency. These components include sensors, controllers, actuators, and communication networks that gather real-time data from various energy-consuming devices. This data is then analyzed to optimize the system's performance, ensuring cost-effective electricity use and minimal waste.

Energy Management Systems Overview

Building Automation and Efficiency

One of the primary ways energy management systems improve efficiency is through building automation. Building managers can monitor and control various aspects of their facility's electricity usage by integrating different systems such as lighting, heating, ventilation, and air conditioning (HVAC) control. This level of control enables them to make informed decisions, reducing power consumption while maintaining a comfortable and productive environment.

Smart Grids and Renewable Integration

Energy management systems also play a significant role in developing and implementing smart grids. These grids use advanced communication technologies and IoT devices to connect renewable energy sources, such as solar panels and wind turbines, with the electric utility. As a result, power supply and demand can be better balanced, leading to more efficient and reliable electricity distribution.

Demand Response and Conservation

Demand response is another crucial aspect of Energy Management Systems, allowing consumers to adjust their consumption based on real-time information from the electric grid. By participating in demand response programs, consumers can reduce their energy consumption during peak hours and benefit from lower costs.

Power conservation is a primary goal of energy management systems, which achieve this through various strategies, including efficient HVAC control, lighting optimization, and equipment scheduling. In addition, businesses and homeowners can significantly reduce their overall power usage by ensuring that power-consuming devices are used only when necessary.

Power optimization is a crucial aspect of EMS, achieved through the ongoing analysis of consumption patterns and equipment performance. Advanced power analytics tools can identify inefficiencies and recommend actions to maximize savings. These insights can help building managers create power-saving strategies, such as adjusting temperature set points, optimizing lighting controls, and scheduling equipment use.

One of the most exciting aspects of energy management systems is their seamless integration of renewable energy sources. By incorporating solar panels, wind turbines, and other clean power technologies, EMS can help businesses and homeowners reduce their reliance on fossil fuels and lower their carbon footprint.

The Role of IoT and AI

The role of IoT and AI in energy management systems is crucial, as they enable remote monitoring, real-time data analysis, and predictive maintenance. By utilizing IoT devices to collect data and AI algorithms to analyze it, EMS can identify inefficiencies and predict equipment failures, thereby ensuring optimal system performance.

By adopting EMS, businesses and homeowners can save money on their power bills and reduce their environmental impact. In addition, by optimizing power use, reducing waste, and integrating renewable energy sources, EMS leads to cost savings and contributes to the global effort to combat climate change.

Future Trends in EMS

The field of energy management systems is constantly evolving, with new trends and innovations emerging regularly. These innovations include integrating energy storage solutions, microgrids, and machine learning algorithms for even more precise power optimization.

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Energy management controls optimize electrical systems via building automation, IoT sensors, BMS/SCADA integration, demand response, and load-shedding to improve power quality, reduce peak demand, and enhance HVAC, lighting, and motor efficiency in industrial facilities.

What Are Energy Management Controls?

Automated systems that monitor, control, and optimize electrical loads to boost efficiency, uptime, and power quality.

✅ Integrates PLCs, BMS, and SCADA for centralized load control

✅ Implements demand response, peak shaving, and load shedding

✅ Meters energy, analyzes power quality, and optimizes setpoints

Energy management controls are conservation tools implemented to control heating, energy consumption, lighting systems, heathing ventilation and air conditioning (HVAC) systems. Modern Direct Digital Control (DDC) systems, which can accurately control building systems, have become very cost-effective in recent years. As a result, they are replacing traditional manual and electromechanical building control systems in retrofitted buildings and being installed in almost all new commercial and institutional facilities. However, maximizing energy efficiency requires strategic facility management control methods for controlling the HVAC, power and communications systems. For a deeper look at modern strategies, the overview at advanced energy management explains integration trends across HVAC and lighting.

Regardless of the technology used, deciding which energy management control mode to apply is important. It is important to understand that these modes can be implemented using many available technology types. In many cases, simple on-off control is adequate and very appropriate. In other cases, the desired effect can be on with modulating controllers. The following are basic control modes. The accompanying diagrams will illustrate typical system performance. Practical frameworks for selecting modes are discussed in energy management systems resources available to facility teams.

The term system capacitance refers to the rate of response of a system to a stimulus. Systems with a large capacitance tend to resist change, and the effects of control are felt more slowly than with systems of smaller capacitance. Comparing the effect to a flywheel or relative mass is a good way to describe this concept. Another useful example to illustrate system capacitance is an instantaneous electric water heater (small volume of water) compared to a standard residential tank-type water heater. Upon energizing the heater elements, the water temperature in the tank unit changes much more slowly because it has more mass, and we say it has greater system capacitance. Understanding capacitance helps in tuning building energy management systems for stability under variable loads.

The term gain is a control term synonymous with sensitivity and is usually an adjustable amplification value used to tune the devices. For example, if a quicker response is desired for a small input change, the gain is increased in a stronger output reaction from the controller. These parameters are typically adjusted within a centralized building automation system interface to synchronize responses across equipment.

On-off Energy Management Controls

Also called two-position control, this rudimentary mode is used with either on or off equipment. A nominal setpoint exists but is only achieved in passing. A range of control values must be tolerated to avoid short-cycling the equipment, and temperature ranges are often fairly wide. In the case of equipment that cannot be modulated, this is often the only choice. The smoothness of control depends strongly upon the system capacitance; systems with very low capacitance can experience short cycling problems using two-position control. In practice, on-off strategies often reflect principles introduced in what is building automation guidance that relates simple control to overall system behavior.

Floating Energy Management Controls

This hybrid combination of on-off and modulating control is also called incremental control. As with on-off control, there is a control range (cut-in/cut out). However, unlike on-off control, floating control systems can maintain a mid-position of the controlled device instead of being limited to full-on or full-off. The controlled device holds its last position between the cut-in and cut-out thresholds. The process variable is not under control within this range, and it floats with the load until it crosses a threshold to get another incremental nudge in the correcting direction. This control is tighter than simple on-off control, and although tight than true modulating control, it is inexpensive and reliable. Equipment items from small HVAC terminal units to 1000 HP water chiller inlet vanes are controlled in this manner with good success. Note that floating control is limited to processes that change slowly, and floating control actuators are usually selected as slow-moving. Selecting floating control as part of a broader energy management approach can reduce wear while maintaining comfort within acceptable bands.

Proportional-only Control (P)

This is the basic modulating control and what most commercial pneumatic and analog electronic systems utilize. It is an error-sensing device with an adjustable gain or amplification. A control output is issued to regulate a process, and the magnitude of the output is directly proportional to the size of the error. This type of control is economical and reliable. However, a characteristic offset (residual error) is natural with this type of controller, and the size of the offset will increase with load. This offset occurs because an error must increase (further off setpoint) before an output increase can occur.

If the proportional energy management controls are too sensitive (gain set too high), the controller’s response will be excessive, and oscillation or hunting will occur. When this occurs, the controller output (and the equipment connected) will oscillate up and down, open and closed, etc., and the control action will not settle out. Training and commissioning within an organized energy management program help operators set appropriate gains and avoid persistent hunting.

Conclusion

Automatic energy management controls are useful for basic regulation and quality control of processes and environments. They can also be leveraged for energy savings through optimization. Properly applied, these systems are reliable and cost-effective. Returning to the chapter's intent, the stated purpose of this chapter was to focus on the application of automatic system controllers as a tool to achieve energy savings. The reader should review the titles of each section, reflect on the key topics taken away, and decide if the stated objective was met. It is hoped that the reader has gained insight into how automatic energy management controls can help achieve energy goals. Therefore, they will endeavour to put these systems to work, optimizing processes and saving energy.

From: Energy Management Handbook, 7th Edition, The Fairmont Press

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Transmission Methods Industrial Networks explain Ethernet/IP, PROFINET, Fieldbus, Modbus TCP, and wireless options, covering deterministic control, latency, throughput, topology, and noise immunity for PLC, SCADA, and IIoT connectivity in factory automation.

What Are Transmission Methods in Industrial Networks?

Methods for transferring industrial data via wired, wireless, and real-time protocols to ensure deterministic control.

✅ Compare Ethernet/IP, PROFINET, Fieldbus, Modbus TCP, and CANopen

✅ Address latency, jitter, determinism, bandwidth, and reliability

✅ Select media, topology, shielding, and QoS for harsh environments

The data communication can be analogue or digital. Analogue data takes continuously changing values.

For a broader systems perspective, building automation fundamentals explain how communication methods underpin monitoring and control.

In digital communication, the data can take only binary 1 or 0 values. The transmission itself can be asynchronous or synchronous, depending on the way data is sent. In asynchronous mode transmission, characters are sent using start and stop codes and each character can be sent independently at a nonuniform rate. The synchronous mode transmission is more efficient method. The data is transmitted in blocks of characters, and the exact departure and arrival time of each bit is predictable because the sender/receiver clocks are synchronized. For an introduction to protocols and media choices, industrial automation communication outlines typical options and tradeoffs.

The transmission methods in industrial communication networks include baseband, broadband, and carrierband. In a baseband transmission, a transmission consists of a set of signals that is applied to the transmission medium without being translated in frequency.

To relate signaling to hardware, industrial network components illustrate how cables, switches, and interfaces shape performance.

Broadband transmission uses a range of frequencies that can be divided into a number of channels. Carrier transmission uses only one frequency to transmit and receive information.

Digital optical fibre transmission is based on representing the ones and zeros as light pulses.

The type of the physical cabling system or the transmission media is a major factor in choosing a particular industrial communication network. The most common transmission media for industrial communication network is copper wire, either in the form of coaxial or twisted-pair cable. Fibre optics and wireless technologies are also being used.

Coaxial cable is used for high-speed data transmission over distances of several kilometers.

The coaxial cable is widely available, relatively inexpensive, and can be installed and maintained easily. For these reasons it is widely used in many industrial communication networks.

Twisted-pair cable may be used to transmit baseband data at several Mbit/s over distances of 1 km or more but as the speed is increased the maximum length of the cable is reduced. Twisted-pair cable has been used for many years and is also widely used in industrial communication networks. It is less expensive than coaxial cable, but it does not provide high transmission capacity or good protection from electromagnetic interference.

Fibre optic cable provides increased transmission capacity over giga bits, and it is free from electromagnetic interference. However, the associated equipment required is more expensive, and it is more difficult to tap for multidrop connections. Also, if this is used for sensor cables in process plants, separate copper wiring would be required for instrument power, which might as well be used for the signal transmission. Higher-speed backbones enable analytics such as advanced energy management that depend on timely, high-resolution data.

In many mobile or temporary measurement situations, wireless is a good solution and is being used widely. Real-world deployments like automated level crossings demonstrate how wireless links support safety-critical automation.

Today's environment

Conventional point-to-point wiring using discrete devices and analog instrumentation dominate today's computer-based measurement and automation systems. Twisted-pair wiring and 4-20 mA analog instrumentation standards work with devices from most suppliers and provide interoperability between other 4-20 mA devices. However, this is extremely limited because it provides only one piece of information from the manufacturing process. Historically, measurement networks and automation systems have used a combination of proprietary and open digital networks to provide improved information availability and increased throughput and performance. Integrating devices from several vendors is made difficult by the need for custom software and hardware interfaces. Proprietary networks offer limited multi-vendor interoperability and openness between devices. With standard industrial networks, on the other hand, we decide which devices we want to use. A concise summary of outcomes such as scalability, diagnostics, and lifecycle savings is provided in benefits of industrial networks for decision makers. Designers can map devices to control, supervisory, and enterprise layers using hierarchical network guidance before selecting vendors.

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Hierarchical Levels Industrial Networks align device, control, and enterprise layers across PLCs, SCADA, MES, and ERP, using fieldbus, Ethernet/IP, and Profinet to ensure deterministic control, real-time data, cybersecurity, and scalable OT-IT integration.

What Are Hierarchical Levels Industrial Networks?

Layered OT networks linking devices, control, and enterprise systems for real-time, deterministic, secure automation.

✅ Defines device, control, and enterprise layers in OT/ICS

✅ Maps PLCs, HMIs, drives, and sensors to appropriate network tiers

✅ Ensures determinism, redundancy, and EMC-compliant cabling practices

The industrial automation systems can be very complex, and it is usually structured into several hierarchical levels. Each of the hierarchical level has an appropriate communication level, which places different requirements on the communication network. Figure 1.1 shows an example of the hierarchy of an industrial automation system. For a broader overview of protocols and trends, industrial automation communication resources explain how hierarchy influences network design across levels.

Industrial networks may be classified in several different categories based on functionality - field-level networks (sensor, actuator or device buses), control-level networks (control buses) and information-level networks. Organizations adopt these layers to gain measurable efficiencies, and the benefits of industry networks include improved interoperability, uptime, and lifecycle support.

We primarily use sensor and actuator buses to connect simple, discrete devices with limited intelligence, such as a photo-eye, limit switch, or solenoid valve, to controllers and computers. Sensor buses such as ASI and CAN are designed so information flow is reduced to a few bits and the cost per node is a critical factor. Selecting cabling, interfaces, and gateways depends on understanding industrial network components that shape reliability, diagnostics, and scalability.

Field level

The lowest level of the automation hierarchy is the field level, which includes the field devices such as actuators and sensors. The elementary field devices are sometimes classified as the element sublevel. The task of the devices in the field level is to transfer data between the manufactured product and the technical process. The data may be both binary and analogue. Measured values may be available for a short period of time or over a long period of time.

For the field level communication, parallel, multiwire cables, and serial interfaces such as the 20mA current loop has been widely used from the 

past. The serial communication standards such as RS232C, RS422, and RS485 are most commonly used protocols together with the parallel communication standard IEEE488. Those point-to-point communication methods have evolved to the bus communication network to cope with the cabling cost and to achieve a high quality communication. Comparisons of copper, fiber, and wireless media, along with signaling and topology choices, are covered in transmission methods for industrial networks to help match performance with environmental constraints.

Field-level industrial networks are a large category, distinguished by characteristics such as message size and response time. In general, these networks connect smart devices that work cooperatively in a distributed, time-critical network. They offer higher-level diagnostic and configuration capabilities generally at the cost of more intelligence, processing power, and price. At their most sophisticated, fieldbus networks work with truly distributed control among intelligent devices like FOUNDATION Fieldbus. Common networks included in the devicebus and fieldbus classes include CANOpen, DeviceNet, FOUNDATION Fieldbus, Interbus-S, LonWorks, Profibus-DP, and SDS.

These characteristics also underpin infrastructure applications such as rail crossings, where distributed sensors and controllers coordinate safety logic, as seen in smart city automated level crossings that rely on deterministic messaging.

Nowadays, the fieldbus is often used for information transfer in the field level. Due to timing requirements, which have to be strictly observed in an automation process, the applications in the field level controllers require cyclic transport functions, which transmit source information at regular intervals. The data representation must be as short as possible in order to reduce message transfer time on the bus.

Control Level

At the control level, the information flow mainly consists of the loading of programs, parameters and data. In processes with short machine idle times and readjustments, this is done during the production process. In small controllers it may be necessary to load subroutines during one manufacturing cycle. This determines the timing requirements. It can be divided into two: cell and area sublevels.

Cell Sublevel

For the cell level operations, machine synchronizations and event handlings may require short response times on the bus. These real-time requirements are not compatible with time-excessive transfers of application programs, thus making an adaptable message segmentation necessary.

In order to achieve the communication requirements in this level, local area networks have been used as the communication network. After the introduction of the CIM concept and the DCCS concept, many companies developed their proprietary networks for the cell level of an automation system. The Ethernet together with TCP/IP (transmission control protocol/internet protocol) was 

accepted as a de facto standard for this level, though it cannot provide a true real-time communication. Similar patterns appear in buildings, where building automation systems integrate HVAC, lighting, and security over IP while reserving real-time tasks for specialized buses.

Many efforts have been made for the standardization of the communication network for the cell level. The IEEE standard networks based on the OSI layered architecture were developed and the Mini-MAP network was developed in 1980s to realize a standard communication between various devices from different vendors. Some fieldbuses can also be used for this level.

Area sublevel

The area level consists of cells combined into groups. Cells are designed with an application-oriented functionality. By the area level controllers or process operators, the controlling and intervening functions are made such as the setting of production targets, machine startup and shutdown, and emergency activities.

We typically use control-level networks for peer-to-peer networks between controllers such as programmable logic controllers (PLCs), distributed control systems (DCS), and computer systems used for human-machine interface (HMI), historical archiving, and supervisory control. We use control buses to coordinate and synchronize control between production units and manufacturing cells. Typically, ControlNet, PROFIBUS-FMS and (formerly) MAP are used as the industrial networks for controller buses. In addition, we can frequently use Ethernet with TCP/IP as a controller bus to connect upper-level control devices and computers.

Information level

The information level is the top level of a plant or an industrial automation system. The plant level controller gathers the management information from the area levels, and manages the whole automation system. At the information level there exist large scale networks, e.g. Ethernet WANs for factory planning and management information exchange. We can use Ethernet networks as a gateway to connect other industrial networks. At this level, analytics platforms often drive energy KPIs, and advanced energy management strategies leverage network data for optimization and demand response.

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