Industrial protocols are communications between industrial automation products for data acquisition or control. In the early days of industrial automation, communications was a competitive differentiator, and automation vendors invented their own communications protocols to both develop a technical advantage and, to some extent, ensure their customer base. This has of course changed over the years and vendors have opened up their protocols, even treating them as industry standards in order to broaden adoption. Vendors have realized that vendors with the largest ecosystem of products to choose from will have a higher likelihood of winning parts of a project, if not the entire project. Suppliers have also realized that it is difficult to be an expert in all areas of automation. Let’s explore several types of industrial protocols and which ones may be compatible with cloud applications.
Types of industrial protocols
Over time, the manufacturing market has become dominated by a set of protocols, naturally from the major vendors of automation products. Before discussing the best ones for the cloud, we can discuss some of the most common industrial protocols. These include protocol names such as Modbus, EthernetIP, Profinet, CC-Link, EtherCAT, etc. Many of these protocols are available in different forms, to suit different topologies – dedicated wires vs. Ethernet, for example – and for different purposes (general information transfer vs. deterministic control).
Standardization efforts over the years have brought us OPC Foundation technology, which was initially based on Microsoft technology, leveraging Windows COM and DCOM technologies for communications between applications. Hence the delivery of OPC (OLE for Process Control – OLE being the acronym for Object Linking and Embedding – the technology behind COM).
OPC provided standards for accessing data, whether polling or subscribing, as well as defining different types of data and how to manage them (analog and discrete variables, historical data , alarms and events, among others). Over time, this standardization effort evolved from being centered on Windows technology to operating system independent, supporting Linux, and providing functionality applicable to Internet-based communications.
The new standard was called OPC UA – OPC now standing for Open Process Communications and UA standing for Unified Architecture, a standard to replace the many earlier standards that had developed.
Another technology, more focused on message transport and less focused on message content, arose from the need for highly distributed infrastructure with limited bandwidth, such as can be found in the upstream oil and gas market. This protocol is called MQTT. Its application in the industrial automation market, especially for cloud communications, has become very popular in recent years.
Vertical markets present unique requirements and have fostered the need for unique developments. In the Building Automation Systems (BAS) space, the main protocol is called BACnet. In the power generation and distribution space, there are a number of protocols, IEC-61850, 60870, DNP-3, among others.
Over time, these protocols have also lived on various topologies, and most offer Ethernet compatibility today.
Why is the cloud so important?
The benefits of cloud computing are many and compelling. They understand:
- Conversion of capital expenditure into operational expenditure
- Eliminate the need to focus on infrastructure management
- Take advantage of a continuously scalable architecture
- Deliver accessibility to your entire organization, anytime, anywhere
- Leverage the services of domain experts (security, upgrades, solution development)
The cloud can take many forms, from a solution provided by industry leaders such as Microsoft and Amazon to more scalable offerings for targeted markets. Finally, there are only hosted solutions, moving on-premises servers to virtual servers in the cloud, but still managed entirely by the owner’s IT staff.
The goal of cloud computing is to provide a lower total cost of ownership through reductions in system management and hardware ownership and the ability to leverage solutions provided by others. These third-party solutions are often purpose-built for a market and offer multi-tenant capability, allowing the service provider to manage many customers while providing data and user isolation. The concept of cloud computing, especially for the industrial market, is still in its infancy and businesses are struggling with both cloud connectivity and the idea of hosting their data outside of their own four walls.
But again, the benefits are compelling: lower operating costs and domain experts who have developed vertical market applications that only require connectivity to the right data. There is another very compelling benefit. Service providers have the ability to leverage insights gained from their wide range of customers and deliver greater value to an individual customer. Thus, the failure mode of a product in one environment can be predicted by failure modes learned in other environments. This results in a potential for predictive analysis, adjusted by the results and the anonymization of data from a similar ecosystem of users. When connecting to the cloud, it is important to determine which industrial protocols will work best for the application.
Things to consider when connecting to the cloud
Considerations for using cloud-based solutions fall into two main categories
- Security (both access security and cybersecurity associated with a data connection)
- Transmission (the reliability and quality of data transfer)
Security is often managed through the use of VPN (virtual private networks). It is an excellent solution for two-way communications and ad-hoc communications, as it is configured for remote troubleshooting purposes. When using VPNs for ad hoc access, customers can take advantage of solutions to secure and negotiate access to endpoints in a very methodical and controlled way. This can include approval processes, access windows and time limits, as well as additional levels of authentication.
For the transfer of information to the cloud, it is increasingly common to use publish-subscribe models and connection brokers to optimize security. Remote sites will publish data over a known and very secure connection, and users of the data, cloud applications, will subscribe to the data through a broker, eliminating the application’s knowledge of remote communication details that represent a vulnerability. Microsoft IoT Hub is a great example of this technology.
Industrial protocols for cloud connectivity
Not all industrial protocols are compatible with cloud applications and should not be. Without going into each protocol and defining whether it can be connected to a cloud, suffice it to say that an overall solution to the connectivity problem will be to deploy state-of-the-art device technology that will handle communications to your IT and OT environment. on one on one side and the requirements for transferring data to the cloud on the other. These devices are beginning to proliferate in the market, some with built-in specific cloud connectivity, and others with a more of a toolkit approach, which can be flexible in their configuration. Most are designed with data transfer as the only function while others support data modeling, analysis and visualization in addition to data transfer.
From an OT perspective, we are again talking about a myriad of protocols and the purpose for which they were defined. And as mentioned earlier, some networks are designed for deterministic performance, for example, communications between a PLC and a SERVO Drive. Such protocols are difficult to share without affecting their performance. Data sharing will be accomplished by communicating with the controller, not with devices on a control network. Other more general protocols often easily connect to a cloud gateway (edge device) in order to share information with the cloud.
Ethernet has improved dramatically over time, both in topology and performance, initially focusing on coaxial cable and now on twisted pair and offering speeds in excess of 1 gigabit. A more recent enhancement is device synchronization and the ability to shape traffic. These features, and many more, fall under an area of Ethernet improvement called TSN (Time Sensitive Networking). TSN provides the ability to prioritize communications over Ethernet and also to control traffic bandwidth. The overall long-term benefits are greater troubleshooting capability – with access to all devices, lower costs – through simplified architectures, and the ability to expose all information to cloud systems.
Even with the breadth of industrial protocols on the market, it is now possible to securely connect virtually any PLC solution to the cloud, either directly or using edge gateways. The challenges we face today are in the area of education and justification, but the benefits are many.