Industrial Automation

DCU Functionality Improving Smart Factory Automation

Julian Vosseler

As companies compete to get their products to market faster and cheaper, they need simple solutions to enable near-immediate implementation. However, there’s no time or budget for special tools or expensive, highly-trained engineers and electricians.

In our previous blog addressing the benefits of Universal I/O Modules for smart factories, we reviewed how universal input/output (I/O) modules allow machine builders to do more with less. Here, we discuss how upgrading to a specific type of I/O module—Distributed Control Units (DCUs)—can deliver new levels of efficiency and affordable automation to smart factories.


There’s a growing decentralization trend in the automation industry to enable the operation of machines and production lines in a more modular way. This means streamlined operations and maintenance (reducing downtime) as well as future-proofed factories and the ability to easily configure upgrades into the existing network. This change is made possible by the addition of programmable logic controller (PLC) functionality into universal I/O modules via DCUs. A DCU supports separate handling of each part of the production line and acts as a single communication device connecting all components.


What Are DCUs?

DCUs are I/O modules with integrated PLC functionality designed to connect sensors and actuators. These devices make automation possible—from simple logic operations to far more complex control challenges. With DCUs, it’s possible without a higher-level PLC, which is more difficult to replace in a production line.



Universal I/O modules are key to the future of machine builders, especially when integrated with DCU functionality. 


Finding an alternative to the PLC is an important advancement for manufacturers challenged to constantly improve efficiency. DCUs execute communication, separate diagnostic data from process data and allow cyber-physical connections—all of which alleviate network traffic burden typically placed on the PLC. This approach keeps operational data from the sensors and actuators close to the affected machine part for easier monitoring. For security reasons, intellectual property from the sub-systems is retained within the machine itself— a more secure and decentralized method over passing intellectual property through the PLC. Easy to install and user-friendly DCUs also provide end-users with more flexibility than ever before. 


Three modes that a DCU could serve in your network.

Standard I/O Slave

Typically, I/O modules always transmit input data to a controller and will only set an output if directed by the controller. By operating in standard I/O slave mode, no program is needed inside the DCU.


DCU/PLC Mixed Mode

In this mode type, the intelligence (control program) sits inside the I/O module however, the application only starts and stops or transmits data to the PLC on command.


Standalone DCU

The intelligence (control program) sits inside the I/O module, therefore no I/O exchange with the PLC is needed to determine what to do with the signals. It is completely independent from any engineering tool, and connection to the PLC is not necessary. This option brings you to “one-device automation.”


How DCUs Are Addressing Market Trends

When applied in an automated industrial setting, DCUs offer functional and financial benefits for machine builders and end-users.

Smart Factories

  • Trends
    • Managing big data and cloud computing requires flexible and innovative approaches to link fieldbus machines with IP network technologies. Manufacturers need intelligent products designed for faster and easier bus coupling of devices—devices able to share event data at any time with the Ethernet network. Easier coupling of devices is paramount when making additions or reconfiguring the parts of a network to reduce downtime.
  • DCUs
    • DCUs can simplify data transmission solutions and adapt existing systems with “plug-and-produce” compatibility making it easier to adapt to current systems and simplify data transmission as it comes from individual machines vs routing to a PLC.
    • TIP: Look for DCUs with multiprotocol options that support the major Ethernet protocols: PROFINET, EtherNet/IP and EtherCat.

Enterprise Innovation

  • Trends
    • Companies are under pressure to upgrade their machines to take advantage of newer Cloud/Ethernet connectivity solutions and protocols, such as OPC UA. Older fieldbus machines however, can’t be monitored via the Cloud or Ethernet. With tight budgets, the automation industry has been forced to make a difficult choice—risk missing out on these advantages or assume the cost of upgrading legacy units. 


  • DCUs
    • DCUs have the ability to make legacy machines Ethernet-ready simply by placing a DCU directly in the machine and tapping into existing sensor data. Doing this mitigates costly upgrades with PLCs or gateways and makes extended use of existing equipment. 

Infrastructure Transformation

  • Trends
    • Ongoing impacts of Industrie 4.0, digitalization and globalization on the automation industry have transformed infrastructure. As more processes are automated, field-level devices can now be installed in harsher environments including those that may have previously been difficult or hazardous to maintain manually.


  • DCUs
    • DCUs mean fast and easy implementation in smart factories. Module exchange is streamlined by the DCU’s “plug-and-produce” nature. This kind of convenience doesn’t have to be sacrificed when applying DCUs in harsh or remote environments, as some DCUs are rated highly enough to withstand the elements. For example, Belden’s DCU was designed to operate in harsh environments across different sectors, such as automotive or food and beverage manufacturing, material handling or packaging and transportation. It can also be used by machine builders or with robotic machinery.


One-Device Automation: With the control program inside the I/O module, no I/O exchange with the PLC (shown above) is needed to determine what to do with the signals. 


How to Start Implementing DCU Applications

More than fast and easy to install, I/O modules featuring DCUs are designed for immediate implementation. I/O modules follow a “plug-and-play” method and are designed to be connected to an existing machine, turned on and be operational without additional configuration.


TIP: Be sure to spec modules with as many inputs or outputs as the current module requires. A plug-and-play-ready module will come with additional adapters to allow for future changes without the drilling of new mounting holes.


Are You Seeing Benefits of Universal I/Os with Your Machines?

Worried about meeting the challenges of increased global competition? Stay ahead of the curve by downloading The Road to Plug-and-Produce white paper.