Optimal IIoT High Frequency PCB Layout Guidelines

November 20, 2019 , in Blog, Industrial

They say, “it’s a small world.” You may ask, “how small is it?” Well, when using the World Wide Web, it seems as though it fits neatly within the desktop, laptop, tablet, or cell phone that you are using at the time. The actual size of this virtual world is dynamic, as the number of devices connected to the internet changes constantly. However, it has been estimated that nearly 60% of the world’s population of 7.7 billion is now Internet-connected. That is an astronomical number, but even more amazing is how fast information and data can be transferred between users, regardless of how remote their locations may be from each other. Information and data exchanges like these are possible due to the underlying high-speed networks and electronics of which they are comprised.

Attributes of IIoT

IIoT Concept

Similar to the internet, Industry 4.0 or what some term the industrial Internet of Things (IIoT) is based on connecting equipment, devices, people and even factories together over high-speed networks comprised of electronics and high frequency PCBs. Within factories, the types of equipment and devices that may be on the network varies greatly depending upon the products made. This presents coordination and synchronization challenges to ensure that all electronics-based systems whether semi or fully autonomous and personnel receive data and information required for production operations in a timely manner. In most cases, the boards that perform the transmission, processing, and reception between systems are high-speed or high frequency.

The development of industrial boards for IoT requires that you follow guidelines to incorporate the environmental conditions of production facilities. This is also necessary for high frequency PCB layout. Let’s take a look at the applications for these boards and how their layout can be optimized, but first, let’s try to clearly define just what IIoT is.

Industry 4.0, IoT and IIoT

Today, we are in the early stages of the fourth industrial revolution. The current transformation of the production of goods, Industry 4.0, is changing manufacturing concepts and processes for not only products but also how those products are made. This includes new equipment, systems capabilities and functionality and electronics, and PCB development.

Industry 4.0 is sometimes used synonymously with the industrial Internet of Things or IIoT. And in some cases, this lack of distinction may be justified as the use of IoT architectures, systems and concepts are a major part of achieving smart, autonomous factory operations and collaborations.  However, it will serve us well to take a moment to clarify these terms.

Industry 4.0 refers to the utilization of automation, robotics, IoT, and data integration to create smart factories. These factories employ equipment, robotics and computing to manage and control manufacturing operations with some degree of autonomy.

IoT or the Internet of Things is the use of software and computing to interconnect equipment, devices and processes in a structured architecture such that data and information transfers can be performed autonomously between equipment and devices without the need for human oversight or intervention. This includes linking to and controlling operations remotely and typically involves cloud computing.

IIoT or the industrial Internet of Things refers to the implementation of IoT concepts, architecture and devices to assist factories or production facilities in the automation of operations and communication between equipment and devices within and external to the plant.

A major requirement for IIoT systems is the ability to transmit, receive and process high frequency signals. These functions are carried out by the high frequency boards used within the system.

High Frequency IIoT Board Applications

High frequency or high speed for IIoT may encompass the following signal types:

IIoT High Frequency Signal Types

  • Data or measurements from electronic, pneumatic or other devices
  • High-resolution image data from sensors
  • Video from cameras for quality control and process security

These signals are typically processed through wireless networks for communication between equipment, robots or cobots and personnel within the plant. Therefore, IIoT boards may be required to process multiple signal types at speeds ranging from tens of MHz to tens of GHz for WiFi transfer, not to mention the power distribution that may include high current traces. For efficient operation, these signals must be networked and distributed among the levels of the IoT architecture optimally.

How to Optimize Your High Frequency PCB Layout for IIoT Applications

High speed boards used in IIoT systems must follow high frequency PCB layout guidelines that adhere to your contract manufacturer’s DFM constraints. Layout design is further complicated by considerations based upon the type or level of automation. These and other environmental considerations necessitate that your PCB layout design follows well-defined guidelines that should include the following:

High Frequency PCB Layout Guidelines for IIoT Boards

  • Choose environment appropriate materials

Boards in industrial environments are likely to be subjected to vibrations or constant motion. To improve durability, flex boards may be used that can withstand these stresses. However, building flex boards can weaken board materials, such as basic FR4. Therefore, you should select materials for high-speed signal propagation and durability.

  • Balance compactness with EMI concerns

Small boards are highly desired for their ability to be mounted almost anywhere. However, compactness means complexity that can place pressure on board manufacture. Reduced space also means less room for spacing between traces, components and other board elements, which increases the possibility that EMI due to high-frequency signals and switching will be a problem. Therefore, you have to balance the need for compactness with the requirements of signal integrity.

  • Pay special attention to thermal dissipation and distribution

Regardless of where your boards are located in the factory, high temperatures may be a concern. When coupled with the heat generated by the board itself, thermal dissipation and distribution can become significant issues, which can alter the board’s dielectric constant and thus impedance. For high frequencies, this can negatively impact signal integrity. Therefore, you should use simulations to evaluate how your board will respond under these conditions and select materials, space components and elements and include thermal reliefs as necessary.

  • Use adequate conformal coating

Moisture, oxidation and perhaps fluids, such as oil drips, may be hazardous for your board, depending on its location. If these fluids or other contaminants land on board traces, they can cause reflections and refractions that can impair signal flow. The best defense is to employ conformal coating to protect your components and traces from its environment.

Tempo‘s Industry 4.0 Custom PCB Manufacturing Services
  • ISO-9001, IPC-600 and IPC-610 commitment to quality certifications.
  • Agile manufacturing process to support risk management.
  • Accurate quote in less than a day.
  • DFM support from Day 1 of design.
  • Entire turnkey PCB manufacturing in as fast as 3 days.
  • High precision, complex PCB fabrication and assembly capabilities.
  • Sources components from the most reputable suppliers in the industry to reduce procurement time and help with component security.
  • Specialization in fast prototyping and low-volume production.
  • Standard quality testing; including X-ray and inline AOI.
  • Advanced QC testing; including flying probe, time domain reflectometry and ROSE.

The ability to transfer data and information at high speed in a requirement for IIoT boards. However, your layout for these PCBs requires additional considerations that most commercial board design does not. By following the guidelines listed above and partnering with a CM that can build your boards to the needed specifications and quality you can ensure reliability operations once deployed in the plant.

At Tempo Automation, building industrial PCBs that meet all of the requirements for industrial environment deployment falls within our areas of expertise. And to help you get started on the best path, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.

If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on high frequency PCB layout guidelines for IIoT, contact us.

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