What a Human Machine Interface system is and How it works

What is a Human Machine Interface system?

An HMI (Human Machine Interface) system is a user interface enabling communication between a machine and a human. Through an HMI system, the machine and the operator can communicate effectively, enhancing the operator's ability to perform tasks comfortably and efficiently.

 

It enables interaction with machines, processes, information, operations, industries, and people. Moreover, it provides complete control over the information received and simplifies interaction with processes through a screen interface.

 

HMI System: Main functions

 

An HMI system allows efficient management of our own and our customers' needs, crucial for optimal process operation:

 

Who can use an HMI system?

 

The platform, employing cutting-edge technology, is user-friendly and accessible to anyone, regardless of their field or expertise, ensuring flawless outcomes. Despite its advanced nature, the interface remains straightforward and comprehensible for operators.

 

Requirements for HMI Systems

 

Every HMI system requires connection to a machine, whether programmed for automatic operation or controlled with human intervention. For the former, the machine necessitates a control interface, typically fieldbus or serial bus. For the latter, the machine requires signal outputs or control contacts manageable via the HMI system.

 

Fieldbus is a control interface utilized by various devices within a system, facilitating communication through exchange of information via communication messages. Currently, two types exist: standard fieldbus and industrial fieldbus.

 

To enable an HMI system to control a machine, the machine must communicate with the fieldbus. Previously, this was achieved by installing a communications card on the PC or machine and connecting it to the fieldbus using an adapter.

 

However, modern PCs or machines equipped with serial and Ethernet ports can now directly manage fieldbus communications. This advancement eliminates the need for an adapter, allowing the machine to send and receive fieldbus communication messages through its serial or Ethernet port.

 

Types of HMI or Human Machine Interfaces

 

Human Machine Interfaces can appear in various formats, including machine screens, computer monitors, touch screens, and smart devices. Regardless of the format or terminology used, their primary objective remains consistent: to convey information about the machine, its production progress, and performance processes.

 

Information received from machines is typically categorized into two main types: statistical information and control information. These types can be combined into supervisory information, which consolidates statistical and control data to offer a comprehensive system overview.

 

Monitoring screens

 

Screens utilized for Human Machine Interfaces are systems capable of interpreting the machine's programming language and visually displaying it. Through a monitoring screen, you can obtain a graphical representation of the machine and manage its operations via programming commands.

 

A diverse range of HMI interfaces exists for controlling machines via screens, available on computers or mobile devices. Touch screens and remote access terminals (TAR) are among the primary interfaces widely used in the industry.

 

Touch screens

 

These screens enable direct user interaction by allowing users to touch the screen to select menus, buttons, and other options. Their popularity has grown significantly in recent years due to advancements in computer systems, offering both comfort and effectiveness in use.

 

Remote Access Terminals (TAR)

 

These computer terminals facilitate remote connections to a local area network (LAN), enabling users to access the network from any location.

 

These interfaces are extensively employed in industrial project management to control processes, providing access to machines across the network. They are classified as data communication or communication tools designed to facilitate interaction between machines and operators.

 

Advantages and benefits of an HMI (Human-Machine Interface) system

 

As previously mentioned, the HMI system plays a crucial role in presenting essential information in a user-friendly manner for optimal machine operation. This includes data such as process temperatures in a factory, pump pressures, and energy consumption levels.

 

The HMI system simplifies human control over machine operations, enabling easy, rapid, and safe management.

 

In contrast to other systems, the HMI system uniquely allows simultaneous access to machine information from multiple locations, such as different machine control stations.

 

Easy and secure access to machine control

 

HMI systems enable operators to access information about various machine components, such as indicators and machine status.

 

User-friendly HMI systems

 

A key advantage of HMI systems is that they do not require specialized training for users to effectively operate the machine via the system.

 

Machine-to-operator communication

 

An HMI system serves as an interface between the user and the machine, facilitating communication through tactile graphical interfaces like tablets, smartphones, or fixed stations located near the machine.

 

Management of machine information

 

With HMI systems, real-time machine information can be accessed, enabling specific operations based on this data. By facilitating control processes and communication between the machine and the operator, HMI systems support optimal machine management.

 

Applications of HMI systems in modern industry

 

HMI systems find applications in visualizing and controlling industrial machines, monitoring industrial processes, managing facilities, and controlling industrial systems.

 

HMI System Applications

 

An instance of HMI system application can be observed in natural gas processing plants, where the HMI system oversees the control and management of natural gas distribution, from raw material acquisition to final product sale. Current HMI systems are employed in various applications such as:

 

Temperature regulation

 

HMI systems utilize techniques like PID (Proportional, Integral, Derivative) control and other methods to regulate temperature. They assist users in maintaining controlled temperatures by displaying essential parameters such as temperature set points, reference values, temperature differentials, and adjustment speeds.

 

Level control

 

Measuring liquid height is essential for level control, which can be achieved through various methods like ultrasonic and fiber optic level measurements. In the case of fiber optic level measurement, the HMI system ensures easy and comfortable operation, providing users with information on liquid levels, differences in levels, adjustment speeds, and more.

 

Pressure control

 

Pressure control involves measuring system pressure using methods such as ultrasonic and fiber optic pressure measurements. With fiber optic pressure measurement, the HMI system facilitates straightforward operation, enabling users to monitor system pressure, pressure differentials, adjustment speeds, and other relevant parameters.

 

How to appropriately select an HMI System?

 

Today, an HMI (Human Machine Interface) is an essential component in all industrial production and automation systems, enhancing operational efficiency and safety. When choosing an HMI, it is crucial to opt for an interface that is easy to operate, effectively resolves security issues, and features a design that minimizes distractions.

 

The development of an HMI should adhere to a user interface engineering process, ensuring thorough consideration during development. This approach reduces product development time and costs, enabling customers to utilize the product efficiently from the outset.

 

When developing an industrial control system, the user interface engineering process typically includes the following steps:

 

• Define user needs.
• Analyze requirements.
• Design the structure of the user interface.
• Design the visual appearance of the user interface.
• Implement the user interface.

 

Furthermore, a robust HMI should feature a comprehensive structure that meets all user requirements. For instance, an HMI might incorporate a TFT panel for data display, a keypad for data input and navigation, screens for displaying alarms and status updates, and screens for configuring products.

 

Phases for selecting an HMI system methodically

 

Phase 1: User Interface Design

 

Designing a user interface involves considering aspects such as ergonomics, functionality, aesthetics, and technology. It can be a complex yet manageable process that integrates functionality, ergonomics, and presentation seamlessly. Effective planning of development phases is essential for success.

 

Phase 2: Structural Study

 

In the second phase of the user interface engineering process, a thorough study is conducted to define the structure of the user interface. This step requires careful planning to encompass all aspects of the industrial control system. Considerations include optimizing maintenance procedures, ensuring efficient information transmission, and providing clear product configuration information.

 

Phase 3: Interface Visual Design

 

The third phase focuses on designing the visual appearance of the user interface. For example, the TFT panel should feature preview images and location indicators for each zone. Clear and effective data display considerations are crucial.

 

Phase 4: Interface Implementation

Implementing the user interface is the fourth phase of the engineering process. It involves determining the best methods for presenting interface data and functions. Efforts are made to enhance data storage efficiency and optimize data presentation for usability.

 

HMI System vs. SCADA System: Choosing Between Them

 

An HMI system is designed for monitoring and controlling individual machines through graphical interfaces like touch screens or Panel PCs. In contrast, a SCADA software operates at a higher level, providing similar functionalities to an HMI but focusing on entire infrastructures rather than single machines. Beyond monitoring and control, a SCADA system includes additional applications to offer a comprehensive view of all facilities and enable informed production decisions: alarm management, data historization or logging in databases, reporting, integration with other industrial and management systems, and more.

 

It's common for HMIs to function as SCADA clients in many projects, serving as monitoring and control interfaces positioned next to each machine across the infrastructure. While there can be overlap in concepts, the primary distinction lies in the self-contained nature of HMIs compared to SCADA clients, which rely on a central SCADA server elsewhere in the plant network. If the server experiences downtime or loses communication with clients, the visualization and control capabilities of these clients may be affected.

 

How to select the ideal HMI?

 

So, which option suits your project best? It's often most practical to incorporate both systems, though the choice ultimately hinges on factors such as communication architecture, budget constraints, network quality, machine criticality, and the need for standardized visualization, among other variables.

 

Would you like assistance in making this decision, with no obligation? At atvise®, we specialize in automating industrial processes using HMI and SCADA systems. This can enhance the performance, productivity, and efficiency of all your industrial operations. Why wait to begin automating your manufacturing processes?

 

How to deploy an HMI system?

 

As mentioned earlier, an HMI system is a powerful tool for organizing and optimizing industrial work processes. Implementation can take various forms: through a custom-built system, a commercial off-the-shelf (COTS) system, or a closed system.

 

For a custom HMI system implementation, a team of experts designs a tailored man-machine system to meet specific company needs.

 

Alternatively, a company may choose to purchase a commercial HMI system from a specialized vendor.

 

When opting for a closed system, it's crucial to verify compatibility with the necessary hardware for seamless operation of the HMI system.

 

Regardless of the approach chosen, proper planning is essential for successful HMI system implementation. It's crucial to determine required functionalities and select software and hardware that best align with the company's operational processes.

 

Steps to Implement an HMI System (Human Machine Interface)

 

At atvise®, renowned for our expertise in industrial process automation and HMI systems, we recommend following these steps for implementing your human-machine interface within your company:

 

Firstly, define the business information that needs to be displayed on the screen. What specific data is required? How should this data be presented? What functionalities are necessary?

 

Once the information display requirements are clear, proceed to select the appropriate hardware. It's advisable to thoroughly explore available market alternatives before deciding on a customized system.

 

After selecting the hardware, configure it to align with your company's production processes.

 

Once the software is configured, install it on the necessary computers. With atvise® HMI SCADA, installation is quick and straightforward, allowing you to start using the human-machine interface software within minutes.

 

Finally, conduct thorough testing of the software to ensure everything operates correctly. At atvise®, we offer a free trial of our HMI SCADA software, enabling you to experience its functionality and versatility compared to other systems available in the market.

 

An often overlooked aspect is personnel training. While implementing an HMI system is expected to streamline operations, it's crucial to provide adequate training to employees to maximize its benefits. Therefore, opting for a system with a short and efficient learning curve, such as atvise® HMI SCADA, is essential.

 

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