Automation engineers working in chemical processing, hydrogen production, refining, and other hazardous industrial environments face a difficult balance between connectivity and installation complexity. Control equipment needs to communicate efficiently with PLCs while also satisfying the requirements of hazardous locations.

Festo has addressed this challenge with an expanded configuration of its VTUG-EX valve terminal, designed for Class I, Division 2 applications. The solution brings fieldbus connectivity closer to pneumatic actuators and is intended to simplify wiring, commissioning, maintenance, and future expansion.

The latest configuration supports EtherNet/IP, PROFINET, and PROFIBUS communication through interchangeable bus nodes and can also connect directly to an IO-Link master.

Why Hazardous-Area Automation Requires a Different Approach

Industrial automation in hazardous locations cannot be designed in exactly the same way as a standard factory floor.

Hydrogen facilities, chemical plants, refineries, and certain processing operations can contain environments where flammable gases or vapors may be present.

In these applications, electrical and pneumatic equipment must be selected and installed according to applicable hazardous-location requirements.

The physical layout of the automation system also becomes important.

A conventional design may place control equipment inside a safe control cabinet and use long cable runs to connect individual valves and actuators in the field.

This architecture is familiar and proven, but it can create significant installation complexity.

Long cable routes increase wiring requirements.

More wiring means more installation work.

More field connections can increase commissioning effort.

And when a production line is expanded, adding additional devices may require additional cable infrastructure.

Festo's approach is to move more communication capability closer to the field equipment.

Bringing Fieldbus Connectivity Closer to the Process

The VTUG-EX valve terminal provides a centralized pneumatic interface while using fieldbus communication to connect the terminal to the PLC.

Instead of running separate control wiring for every actuator back to a remote control cabinet, the fieldbus architecture allows multiple pneumatic functions to communicate through a network connection.

This can significantly change the physical architecture of an automation system.

The basic concept is:

PLC → Industrial Ethernet / Fieldbus → Valve Terminal → Pneumatic Actuators

The PLC remains the central control authority.

The valve terminal provides the local interface between electrical communication and pneumatic actuation.

This approach can reduce the amount of point-to-point wiring required between the control cabinet and field devices.

For system integrators, the result can be a cleaner installation and easier expansion.

EtherNet/IP, PROFINET and PROFIBUS Support

One of the practical advantages of the VTUG-EX approach is communication flexibility.

Festo states that the terminal supports EtherNet/IP, PROFINET, and PROFIBUS through interchangeable bus nodes.

This is important because industrial plants rarely use one universal communication architecture.

Different industries and customers may standardize on different PLC platforms and networks.

For example, an automation project based on a Rockwell Automation PLC may use EtherNet/IP, while a Siemens-based system may use PROFINET.

Legacy process plants may continue to operate PROFIBUS infrastructure alongside newer Ethernet-based systems.

Providing multiple communication options allows integrators to adapt the pneumatic system to the existing control architecture.

This can be particularly useful during modernization projects where the goal is to upgrade automation without replacing the entire plant control system.

IO-Link Adds Another Layer of Device Connectivity

The VTUG-EX can also connect directly to an IO-Link master.

IO-Link has become increasingly important in industrial automation because it allows intelligent field devices to exchange more information than a simple discrete signal.

Traditional sensors often provide only an on/off state or an analog value.

IO-Link can provide additional diagnostic and parameter information depending on the connected device.

For automation engineers, this creates opportunities to improve device monitoring and maintenance.

A system can potentially identify abnormal device behavior earlier, simplify parameterization, and provide additional information to the control system.

In a hazardous-area application, this type of device-level information can be valuable because maintenance access may be more complicated than in a conventional production environment.

Reducing Wiring Complexity

One of the biggest practical benefits of decentralized fieldbus architecture is wiring reduction.

Traditional pneumatic automation can involve large quantities of individual electrical connections.

Each solenoid valve may require separate wiring.

As the number of actuators increases, the control cabinet and cable infrastructure become more complicated.

Fieldbus-based valve terminals change that model.

Multiple pneumatic outputs can be grouped into one intelligent field station.

The station communicates with the PLC through a network connection rather than requiring individual control wires for every channel.

This can reduce panel congestion and simplify cable management.

For large plants, the effect can become substantial.

Faster Commissioning and Troubleshooting

Installation complexity has a direct impact on commissioning time.

Every additional cable creates another potential connection point that must be checked.

During commissioning, engineers need to verify wiring, signal assignments, device addressing, valve operation, and PLC logic.

A decentralized fieldbus architecture can simplify this process because device communication is consolidated.

Troubleshooting can also become more systematic.

Instead of starting with dozens of individual control wires, technicians can examine the communication status, valve-terminal diagnostics, I/O status, and PLC data.

This is especially useful when a pneumatic actuator fails to respond.

The troubleshooting sequence can be structured around several layers:

1. Check PLC command.
2. Check network communication.
3. Check valve-terminal status.
4. Check output channel.
5. Check pneumatic pressure.
6. Check actuator movement.

This layered diagnostic approach can help maintenance teams isolate faults more quickly.

Importance for Hydrogen Automation

Hydrogen is emerging as an important application area for advanced automation.

Hydrogen production, storage, compression, and processing involve specialized equipment and safety requirements.

Automation systems may need to control valves, actuators, pressure systems, cooling equipment, and process instrumentation.

The combination of hazardous-location requirements and increasing automation density makes decentralized control particularly attractive.

Festo specifically identifies hydrogen, chemical, and refining applications as target areas for the VTUG-EX solution.

The broader trend is toward placing intelligent field devices closer to the process while maintaining centralized supervisory and control functions.

Decentralized I/O Is Changing Control Cabinet Design

The move toward decentralized automation is not limited to pneumatic systems.

Industrial automation manufacturers are increasingly placing I/O, motor control, valve control, and diagnostic functions closer to machines and processes.

This reduces the dependency on large centralized control cabinets.

For PLC engineers, the change means that system architecture is becoming more distributed.

A modern automation project may include:

• Central PLC
• Remote I/O
• Distributed valve terminals
• Variable frequency drives
• Servo drives
• IO-Link devices
• Industrial Ethernet switches
• Safety I/O
• Edge computers

The PLC remains central to control logic, but the physical I/O architecture becomes increasingly decentralized.

Industrial Ethernet Is Becoming the Common Infrastructure

The support for EtherNet/IP and PROFINET is also representative of a larger industry trend.

Industrial Ethernet is becoming the dominant communication infrastructure for modern automation systems.

Compared with traditional point-to-point wiring and older fieldbus architectures, Ethernet-based systems can support larger quantities of data and integrate more easily with higher-level industrial systems.

However, this also means engineers need to consider network design more carefully.

Switch configuration, topology, redundancy, addressing, diagnostics, cybersecurity, and device interoperability all become important.

For hazardous-area automation, these considerations must be combined with the applicable electrical and installation requirements.

Modernization Without Rebuilding the Entire Plant

One of the strongest use cases for flexible valve-terminal architecture is modernization.

Many industrial plants contain control systems that have been operating for years or decades.

Replacing an entire PLC and DCS infrastructure may be expensive and disruptive.

A more practical approach is often to modernize selected field-level components while maintaining the existing control strategy.

A valve terminal that supports multiple communication architectures can help integrators adapt pneumatic systems to different generations of PLC technology.

This is particularly valuable for brownfield projects.

The plant can retain its existing process equipment while gradually improving field connectivity and diagnostics.

What This Means for PLC Engineers

For PLC engineers, the increasing use of decentralized valve terminals means that pneumatic control is becoming more integrated with the digital automation network.

The engineer is no longer simply programming individual outputs.

The system may involve network configuration, device diagnostics, I/O mapping, parameterization, communication monitoring, and integration with higher-level systems.

This creates a more structured automation environment.

A fault can be analyzed through communication diagnostics instead of only through physical wiring.

Device information can be integrated into maintenance systems.

Additional field devices can potentially be added with less cabinet modification.

The result is a control system that is easier to scale.

The Future of Hazardous-Area Automation

The latest VTUG-EX development reflects a broader direction in industrial automation: bringing digital connectivity closer to the physical process.

Factories and process plants are becoming more distributed, connected, and data-driven.

At the same time, hazardous industries cannot sacrifice safety and reliability for connectivity.

The challenge is therefore to create automation architectures that combine robust field equipment, industrial communication, PLC control, diagnostics, and appropriate hazardous-location protection.

For chemical plants, refineries, hydrogen facilities, and other process industries, this is becoming increasingly important.

Festo's latest VTUG-EX capabilities show how pneumatic automation is adapting to this environment.

Instead of treating valves and actuators as simple field devices, modern automation architectures are turning them into connected components of the industrial control system.

That shift will continue to influence PLC programming, control cabinet design, industrial networking, commissioning, maintenance, and plant modernization.