Today, industrial HMIs are much more than simple interfaces between an operator and a machine. They are a central component of the digital architecture of modern factories, enabling the control of equipment, the monitoring of industrial processes, and the visualization of production data in real time.
As companies accelerate their digital transformation, expectations for human-machine interfaces are evolving. Production managers, maintenance teams, and industrial IT departments are no longer looking solely for a local control display. They want a platform capable of centralizing information from multiple production lines, facilitating integration with SCADA and MES software, while ensuring the long-term value of their investments.
The choice of an industrial HMI should therefore no longer be considered solely from a hardware perspective. It is now an architectural project that directly influences operational performance, production continuity, and the plant’s ability to evolve toward Industry 4.0 standards.
Human-machine interfaces were primarily used to control a machine or monitor a PLC. While this function remains useful, it is no longer sufficient for modern factories. Today, industrial sites consist of numerous production lines with a variety of equipment, which increases the number of tools and data sources.
Industrial HMI systems thus serve as a bridge between the shop floor and supervision, centralizing information and providing a comprehensive view of performance. This evolution is driven by several underlying trends:
For industrial IT managers, the HMI is thus becoming a strategic component on par with PLCs, industrial networks, and monitoring platforms.
A Human-Machine Interface (HMI) is a hardware, software, or hybrid solution that enables operators to interact with industrial equipment. It serves as the point of contact between users and automated systems. Specifically, an HMI allows users to:
Contrary to popular belief, an HMI does not operate in isolation. It is integrated into a broader architecture that includes programmable logic controllers (PLCs), SCADA systems, MES software, and sometimes data analytics platforms or cloud services.
It is this ability to integrate that today distinguishes a simple operator interface from a true industrial HMI system.
In a connected factory, information flows through a hierarchical architecture where each level fulfills a specific function.
At the base of this architecture, sensors and machines generate production data. Programmable logic controllers (PLCs) execute control programs and transmit information to the HMIs. These HMIs allow operators to interact with the equipment and view operating statuses before the data is forwarded to a supervisory platform that centralizes multiple production lines.
In recent architectures, an edge computing layer is inserted between the shop floor and the supervision system. As a result, industrial PCs or edge servers preprocess the data, thereby reducing latency and maintaining continuity in the event of a network outage.
This approach meets the needs of real-time performance analysis and industrial artificial intelligence projects.
Not all human-machine interfaces meet the same needs. The choice depends on the size of the facility, production constraints, and monitoring objectives.
Panel PCs combine a touchscreen and an industrial computer in a single unit. They are widely used for the local control of machines and automated cells.
Their rugged design allows them to operate in demanding environments subject to vibrations, dust, or temperature fluctuations. They are now the preferred solution for new installations and retrofit projects.
Some architectures rely on a software application installed on an industrial PC or an operator station. This approach offers greater flexibility for updating graphical interfaces and facilitates integration with SCADA platforms.
It is particularly well-suited for workshops with multiple monitoring stations.
Web HMIs use a web browser as the user interface. This technology simplifies deployment across multiple workstations and facilitates secure remote access. With the widespread adoption of web-based architectures, this type of HMI is seeing strong growth in industrial modernization projects.
Thin clients perform virtually no local processing and display interfaces hosted on a centralized server. This architecture simplifies maintenance and updates, particularly in large, multi-workstation plants.
Each approach offers specific advantages. The choice depends on the required level of availability, cybersecurity constraints, IT policy, and the company’s long-term objectives.
Not all human-machine interfaces are created equal. In a modernization project or when setting up a new production line, the choice of an HMI should not be based solely on price or technical specifications. It must integrate seamlessly into the industrial architecture and support the evolution of the production equipment over the long term.
Here are the key criteria to consider before investing.
In many factories, production lines were installed at different times, resulting in heterogeneous interfaces and scattered data. This complicates troubleshooting and reduces overall visibility into production. A modern HMI must centralize multi-line monitoring and unify the interfaces.
The most sought-after features include:
- consistent navigation across all lines;
- centralized alarm management;
- a common event log;
- multi-workshop dashboards;
- an interface tailored to both operators and maintenance teams.
This consistency not only improves user experience but also reduces training time for new operators.
You now have a considerable volume of data at your disposal. However, this information often remains underutilized due to a lack of suitable tools. A modern HMI no longer simply displays a machine’s status. It must provide a dynamic view of performance to help teams make decisions quickly.
The goal is to transform production data into directly actionable metrics. Among the most commonly tracked metrics are:
Real-time access to this information allows for intervention before a production deviation becomes a serious problem.
Industrial projects rarely rely on a single manufacturer. A single plant may combine PLCs from Siemens, Schneider Electric, Rockwell Automation, or Mitsubishi Electric, along with specialized equipment from numerous manufacturers.
In this context, an HMI must be able to communicate with heterogeneous environments without requiring multiple custom developments. Open protocols facilitate this interoperability and limit the risk of dependence on proprietary technology. The most widely used standards today are:
- OPC UA;
- MQTT;
- Modbus TCP;
- EtherNet/IP;
- Profinet.
Choosing a solution compatible with these protocols simplifies future modernization projects and reduces integration costs.
The convergence of IT and OT networks exposes production equipment to greater cybersecurity risks. New regulations, such as the NIS2 Directive, as well as the recommendations of the IEC 62443 standard, encourage manufacturers to strengthen the protection of their systems. A modern HMI must therefore offer appropriate security mechanisms, including:
- granular user rights management;
- secure authentication;
- complete traceability of actions performed;
- segmentation of network access;
- regular updates to software components.
Cybersecurity should no longer be considered an optional feature, but rather a selection criterion in its own right.
Few companies today replace all of their equipment at once. Most projects are carried out gradually, line by line, to minimize production downtime.
The chosen architecture must therefore be sufficiently scalable to integrate new equipment without disrupting the entire system. A scalable solution facilitates, in particular:
- the addition of new production lines;
- the gradual replacement of older HMIs;
- the integration of new PLCs;
- the deployment of additional supervisory workstations;
- integration with MES or cloud applications.
This scalability is a key driver for long-term cost control.
Obsolescence is one of the main reasons for replacing industrial HMI systems. When a manufacturer discontinues sales or support for a product line, the consequences can be significant: unavailability of replacement parts, incompatibility with new operating systems, or the inability to upgrade the existing application.
Before selecting a new platform, it is therefore recommended to evaluate:
- the manufacturer’s stated lifespan;
- the availability of spare parts;
- the software maintenance policy;
- the possibilities for migrating to future versions.
Anticipating these factors as early as the design phase helps avoid costly replacement projects a few years down the line.
A high-performance HMI is not measured solely by its technical specifications. Its ergonomics directly influence operational quality and the speed at which teams can respond. An overloaded or poorly organized interface increases the risk of errors and prolongs diagnostic times.
Best practices include:
- using consistent navigation across all lines;
- prioritizing alarms based on their criticality;
- limiting the amount of information displayed at one time;
- adopting a consistent graphical representation of equipment.
The goal is to enable an operator to quickly identify an anomaly and immediately understand the actions to be taken.
The purchase price of an HMI represents only a portion of its actual cost. To compare two solutions, it is best to use an approach based on total cost of ownership (TCO). This analysis takes several factors into account:
- hardware;
- software licenses;
- updates;
- integration services;
- maintenance costs;
- user training;
- future migrations.
In many industrial projects, a solution that is slightly more expensive to purchase proves to be more cost-effective over a ten- or fifteen-year period thanks to simplified maintenance and better scalability.
This comparison shows that expectations for HMI systems have changed significantly. Companies are now looking for platforms capable of integrating into an overall industrial architecture, supporting digitalization projects, and providing reliable data to improve operational performance.
HMI replacement projects are often driven by hardware obsolescence. However, simply replacing the screens without revising the overall architecture amounts to replicating the limitations of the existing installation. The main mistakes observed are:
- maintaining different interfaces across different workshops;
- choosing a proprietary solution that is difficult to upgrade;
- neglecting future connectivity needs;
- underestimating cybersecurity requirements;
- failing to involve production and maintenance teams from the design phase onward.
Conversely, a comprehensive approach that integrates user needs, network architecture, production monitoring, and future expansion plans enables the development of a more sustainable solution and optimizes return on investment.
In industrial modernization projects, replacing industrial HMI systems is rarely a standalone effort. It is part of a comprehensive transformation aimed at improving monitoring, data reliability, and line performance.
In a multi-line plant, equipment is often heterogeneous: PLCs from different generations, varied interfaces, and non-standardized monitoring systems. This complicates operators’ work, extends training times, slows down incident diagnosis, and limits overall production visibility.
Modernization generally rests on three pillars:
- standardized industrial panel PCs for operator interfaces;
- centralized SCADA monitoring for multi-line management;
- an edge computing layer for data collection and preprocessing.
This homogeneous architecture enables real-time access to data and improvesits utilization at all levels of the plant. The main benefits observed are:
- reduced diagnostic times;
- improved line availability;
- standardization of operator practices;
- better utilization of production data;
- simpler system upgrades.
This type of project demonstrates that industrial HMI systems are fundamental components of industrial architecture, not merely local interfaces.
Industrial HMI systems have become central to factory modernization, going beyond the simple role of an operator interface. They are integrated into a comprehensive architecture for real-time monitoring and performance analysis.
The selection of these systems should not be made in isolation but must be integrated into the overall industrial strategy, taking into account multi-line supervision, interoperability, cybersecurity, and scalability.
Anticipating these challenges enables the construction of more efficient, resilient factories that are well-suited for Industry 4.0.
What is the difference between an HMI and a SCADA software?
An HMI is a local interface that allows an operator to control a machine or a production line. A SCADA software, on the other hand, monitors multiple pieces of equipment, centralizes data, and enables a comprehensive analysis of production at the factory or industrial site level.
How do you choose an industrial HMI suitable for a multi-line factory?
The choice depends primarily on several criteria: the ability to monitor multiple lines, interoperability with existing PLCs, cybersecurity, the solution’s scalability, and its ability to provide real-time performance metrics. A total cost of ownership analysis is also essential.
Why are industrial HMI systems essential in Industry 4.0?
They serve as the point of interaction between operators and automated systems. In the context of Industry 4.0, they enable machines to be connected, production data to be centralized, and actionable insights to be provided to improve industrial performance.
What are the current trends in industrial HMIs?
The main developments include the widespread adoption of web-based architectures, the integration of edge computing, the use of open protocols such as OPC UA or MQTT, and stricter industrial cybersecurity requirements.