Valve Terminals: An Essential Component in Industrial Automation

In modern times, the industry is constantly evolving, and the process of industrial automation is constantly moving towards improved efficiency, precision, and reliability. In these automated systems, pneumatic technology is utilized, which powers everything that includes robotic grippers and the machinery used for packaging. In the industries, these systems are being designed to be smart, compact, and highly integrated, which makes the traditional wiring and piping for each individual pneumatic system a thing of the past. This is where a valve terminal becomes a perfect solution for industries, offering a centralized pneumatic control system to provide a significant increase in reliability and efficiency of automated production lines.

If you are an engineer or a system integrator, this article would provide you with all the fundamental knowledge of the mechanics, architecture, benefits, and applications of valve terminals to optimize an industry's pneumatic control architectures.

Introduction to Valve Terminal

For industrial automation, many industries utilize pneumatic valves to improve the automation process. So instead of having individual wiring and piping across multiple directional control valves individually, manufacturers have come up with a much more reliable and efficient solution known as valve terminals. The main purpose of having these valve terminals in industries is to ensure multiple valves are integrated into a single, compact, and highly organized unit.

A valve terminal is designed to give operators centralized control of multiple pneumatic actuators, like cylinders, rotary actuators, and grippers, from a single unit. To ensure an efficient centralized control, these valve terminals combine the pneumatic distribution and the electrical control interface, such as the communication signals for Programmable Logic Controller (PLC), and the compressed air from a compressor is directed towards the required pneumatic canal to perform a required function.

Before these valve terminals were introduced, the pneumatic systems required individual, extensive wiring and air supply lines for controlling the valve functionality, which made the troubleshooting process difficult and highly complex. With the introduction of valve terminals, it replaced the complex wiring and the disorganized polyurethane tubing with a centralized system that is much cleaner, more organized, and easier to communicate and control.

How Valve Terminals Work

In this section of the article, we will be exploring the working of valve terminals that ensure an efficient pneumatic control system, simplifying the process of airflow and signal processing.  

Pneumatic Pathway

Behind every opening or closing of a pneumatic valve, air flow is required. For a valve terminal to operate, there is a main entrance where the compressed air enters the system, which is then divided into the precisely engineered channels that direct the air to the required valve. So when an electrical signal is sent to a specific solenoid, the internal spool or the poppet shifts to that specific working port, which is connected to the pneumatic actuator, which causes it to extend, retract, or rotate.

After the actuator completes the required stroke, the air is required to be exhausted. In the exhaust process, the air goes back to the working port and back into the valve terminal. To minimize the noise created by the exhaust air, instead of exhausting directly at the valve, the exhaust air is removed through a common internal exhaust channel, which has a centralized silencer installed, which helps to significantly reduce the noise of the floor.  

Valve Configurations

Valve terminals are regarded as very versatile because they have several kinds of valve designs based on the mechanical needs.

• 5/2 Valves: These valves are utilized in managing two-acting cylinders.

• 3/2 Valves: These are applied to the single-acting cylinders to perform the function of blow-off.

• 5/3 Valves: These valves are good for maintaining a center position, such as closing, opening, exhausting, or pressurizing, or to maintain an intermediate position that needs to stop or hold the load.

Components of Valve Terminals

For the valve terminals to operate properly, there are some key components and an architecture that operates as a system to ensure intended efficiency and performance. 

The Manifold Base (Subplate)

The subplate is where all the components are attached. These baseplates are usually made from a very durable and lightweight metal, such as anodized aluminum or high-grade engineered plastic material, providing a structural support for valves. Furthermore, the internal passageways are present to direct the air for the supply and exhaust, distributing the air to the required valves without the need for running individual piping for the air supply. 

Pneumatic Solenoid Valves

Pneumatic solenoid valves are the moving parts that are located on the top of the bases. When these solenoid valves receive electronic signals, they can open or close instantly to let the air pass through. The best part of these modern valves is that they require extremely low power and can operate for multiple cycles efficiently, offering longer lifespans. These systems allow users to mix and match them with different valve sizes to perform different functions and to suit varying flow requirements. 

Electrical Control and Communication Interfaces 

Electrical signals have an important role in the modern era of Industry 4.0, where automation is increasingly becoming a necessity in the opening and closing of the valve by receiving commands issued by the main controller that regulate the flow of air. Such standard connections are:

• Multi-pin Connectors: Example includes D-SUB 25-pin connectors, which are responsible for the wiring of all the solenoids into a single plug. 

• Fieldbus and Industrial Ethernet: These nodes feature advanced terminals like PROFINET, EtherNet/IP, or EtherCAT, building up the connection to controls for the operator on the factory network. 

• IO-Link Integration: With IO integration, the operator can remotely change the valve configuration, get data on what part is malfunctioning, and allow integration with the factory's network. 

Benefits of Using Valve Terminals

When it comes to using valve terminals, there are various benefits in terms of operations and automation for an industry. Some of these benefits are mentioned below: 

• Space Optimization: With a centralized pneumatic valve system that is controlled by valve terminals, it significantly reduces the space occupied by the pneumatic control system, making the design of the machine a lot more compact. 

• Reduction in Installation and Wiring Time: Wiring for multiple individual solenoids can be time-consuming compared to wiring a single multi-pin connector or an Ethernet cable, which reduces the overall assembly time and labor costs. 

• Enhanced Diagnostics and Maintenance: Smart valve terminals with IO integration help in troubleshooting any of the problems occurring in the production line without being physically present on the field, saving industries' downtime.   

• Energy Efficiency: With a centralized valve that is much closer to the actuator, the length of the tubing is reduced, and also reduces the dead volume of the air, meaning the energy consumed in pressurizing and compressing the air is less. 

Applications for Valve Terminals

In a valve terminal, there is a wide variety of applications in the industries where pneumatic valves are typically highly used. Some of those applications are mentioned below: 

Automotive Manufacturing and Assembly

In automotive manufacturing and assembly lines, work is automated and is typically done by industrial clamps, robotic grippers, and indexing tables. To simultaneously control all of these, valve terminals are used because they offer high resistance to vibration and provide reliable communication, which makes them an ideal choice for the automotive industry. 

Packaging and Palletizing

The machines used for packaging are required to be able to operate at high speeds, and should have well-synchronized movements to ensure that folding boxes, filling containers, and sealing packages can be done with ease. This is where valve terminals come in as a great option, offering very low response time and space-saving designs that are great for packaging applications. 

Electronics Assembly

For electronics assembly, the two important things that matter are space saving and precision. Compact and lightweight valve terminals can be a perfect fit as they can be mounted directly onto the moving robotic arms to not only save space but also ensure precision. 

Finding the Right Valve Terminal

When it comes to valve terminals, there are multiple options to pick from. Picking the right one can make or break your engineering project. 

Sizing and Flow Rate Requirements

Pneumatic valves operate on airflow. The valve terminals supplying them with air should be capable of supplying the required airflow. It is typically measured in CFM or L/min. Ensuring that the supplied flow matches the specifications of the pneumatic valve actuator is vital. To calculate this: 

Qreq= Qtotalfs (1+ms)

Here:

• Qreq (Required Flow Rate): It tells the size of the valve you need to get, typically measured in CFM or L/min. 

• Qtotal (Total Air Consumption): The maximum amount of Air the system would use, given that every single cylinder will actuate at the same time. The total can be found by summing up the consumption rate of the individual cylinders. 

• fs (Simultaneity Factor): It is the factor that defines how many cylinders fire at the same time. 

• ms (Safety Margin): Typically, 0.2 to 0.3, defining the margin for the pressure drop to ensure you don’t get undersized valves. 

Electrical Connectivity and Control Architecture

This factor would determine how your terminal will be able to communicate with the PLC. If you just require controlling simple machines, a 24V DC multi-pole connection is good enough. However, if the industry requirements are based on data-driven automation, it's better to go for a valve terminal that has integrated IO-Link or Fieldbus connectivity, which makes the maintenance and troubleshooting process a lot easier and minimizes the time-consuming wiring for individual solenoids. 

Environmental Ratings

For valve terminals, environmental rating can vary, but you must choose the right option after you have assessed the operating environment. Well, for a terminal that is being used in an indoor protective cabinet, an IP40 rating would be sufficient. However, if the terminal is directly mounted to the machine frame and is exposed to dust, coolant, or cleaning procedures, it is recommended to go for higher IP ratings like IP65, IP67, or even IP69K-rated enclosures to ensure the sensitive internal electronics are kept protected. 

Safety and Compliance Considerations for Valve Terminal Systems

In any industry, the safety of the human operators or the machinery should be the utmost priority of the industry. To ensure these safety standards are guaranteed, the following are some of the compliance factors that should be taken into consideration: 

• Safe Exhaust and Noise Reduction: When operating pneumatic valves, the major concern is the high noise levels produced when the air is exhausted. So when choosing a valve terminal, ensure high-quality silencers are used on exhaust ports to ensure workers are protected from hearing damage. 

• Pressure Zones and Safe Torque Off (STO): Some of the advanced air terminals feature multiple isolated pressure zones. These zones help to remove air from hazardous actuators like heavy presses or clamps and keep the air pressure in the workholding device to prevent the parts from failing. 

• Industry Certifications: Ensure the components are approved and have renowned industry certifications like CE, UKCA, UL, and ISO certifications to ensure consistency is maintained in manufacturing quality. 

Conclusion

In almost every industry where there is automation, which includes robotic arms, grippers, and clamps, they utilize pneumatic valves. No industry wants to deal with the time-consuming and cost-heavy wiring and the installation process of these standalone solenoid valves. A valve terminal solves all these problems by providing a centralized control system for all these valves with a centralized electrical connection, making the troubleshooting and installation process a lot easier. Valve terminals are now becoming a major requirement for every industry that is looking to move towards automation or improve its automation process. So if you are an engineer, a contractor, a factory manager, or an owner of the industry looking to improve automation in the industry, ensure that you follow the safety protocols and select the right valve terminal based on your industrial application by following the guidelines above to ensure your industry requirements are fulfilled. 

Just as choosing the right valve terminal is essential, choosing the right manufacturer is just as important. So if you're looking to upgrade your pneumatic architecture, our recommendation would be Titan Automation. With over 26 years of industry experience and with exports across 60 countries,  they have built a reputation for providing one-stop, fast, and cost-effective pneumatic solutions necessary to drive your automated systems into the future.

FAQs

Q1: What is the main difference between a valve terminal and a standalone solenoid valve?

A standalone solenoid valve can be used only for controlling a single actuator, which requires its own separate air supply, exhaust, and wiring. On the other hand, a valve terminal can be used to simultaneously control multiple solenoid valves on a single baseplate, utilizing a common air supply, common exhaust, and a centralized electrical connection, which helps to simplify the control and troubleshooting process of the system.  

Q2: Can I mix different valve sizes or functions on the same valve terminal?

Yes, many of the valve terminals allow for the integration of various valve sizes from 10mm to 14mm and different functions that include 3/2-way, 5/2-way, and 5/3-way, all on the same manifold base. 

Q3: What is the standard operating voltage for industrial valve terminals?

The industrial valve terminals that you can commonly find operate at 24V DC, which is usually the standard operation voltage of industrial automation, PLCs, and safety circuits. 

Q4: Are valve terminals suitable for harsh manufacturing environments?

It depends on the type of protection offered by the manufacturer. If you are looking to use valve terminals in harsh environments, look for IP65 or IP67 ratings. The terminals with these ratings have an enclosure that protects them from dust and low-pressure water jets, which allows them to be mounted directly on the machine instead of a separate control cabinet.