Industrial protocols are communications between industrial automation products for data acquisition or control. In the infancy of industrial automation, communications were very much a competitive differentiator, and automation vendors invented their own communication protocols to both develop a technical advantage and, to some extent, lock in 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 realized that suppliers with the largest ecosystem of products to choose from will have a greater likelihood of winning parts of a project, if not the entire project. Vendors also realized that it is challenging to be an expert in all areas of automation. Let’s explore several types of industrial protocols and those that may be compatible with cloud applications.
Types of Industrial Protocols
Over time, the manufacturing marketplace became dominated by a set of protocols, understandably from the leading suppliers of automation products. Before discussing which are best 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 address varying topologies – dedicated wires vs. Ethernet, for example – and different purposes (general information transfer vs. deterministic control).
Efforts in standardization over the years brought us technology from the OPC Foundation, which was initially Microsoft technology-based, leveraging COM and DCOM Windows technologies for communications between applications. Hence, the delivery of OPC (OLE for Process Control – OLE being an acronym for Object Linking and Embedding – the technology behind COM).
#1: OPC
OPC brought standards for accessing data, either polling or subscribing, and the definition of different data types and how to handle them (Analog and Discrete variables, History Data, Alarms, and Events, among others). In time, this standardization effort moved from being Windows technology-centric to being Operating System-agnostic, to supporting Linux and delivering functionality that would be applicable to Internet-based communications.
#2: OPC UA
The new standard was called OPC UA – with OPC now representing Open Process Communications and UA representing Unified Architecture, one standard to replace the many earlier standards that had developed.
#3: MQTT
Another technology, more focused on the transport of messages and less focused on the content of messages came out of the need for a very distributed infrastructure with limited bandwidth, as can be found in the upstream oil and gas marketplace. This protocol is called MQTT. Its application in the industrial automation marketplace, especially for cloud communications, has become quite popular in recent years.
#4: BACnet
Vertical markets present unique requirements and have fostered the need for unique developments. In the Building Automation Systems (BAS) space, the leading 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 today, offer Ethernet compatibility.
Why is the Cloud So Important?
The benefits of cloud computing are numerous and compelling. They include:
- Conversion of capital expenses to operational expenses
- No longer needing to focus on infrastructure management
- Leveraging a continuously scalable architecture
- Delivering accessibility to your entire organization, anywhere and anytime
- Leveraging services from domain experts (security, upgrades, solution development)
The cloud can take several forms, from a solution delivered by industry leaders such as Microsoft and Amazon to more scaled offerings for targeted markets. Finally, there are just hosted solutions, moving on-premise servers to virtual servers in the cloud, but still fully managed by the owner’s IT staff.
The purpose of cloud computing is to offer 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, letting the service provider manage many customers while offering data and user isolation. The concept of cloud computing, especially for the industrial marketplace, is still in its infancy and companies are wrestling with both cloud connectivity and the idea of hosting their data outside their four walls.
But again, the benefits are compelling: reduced operating costs and domain experts that have developed vertical market applications that only require connectivity to the right data. There is one other very compelling benefit. Service providers have the ability to leverage knowledge gained over their large array of customers and deliver greater value to an individual customer. So, the failure mode of a product in one environment can be predicted by the failure modes learned from other environments. This results in the potential for predictive analytics, tuned by the results and anonymization of data from a similar ecosystem of users. When connecting to the cloud, it’s important to consider which industrial protocols will work best for the application.
What to Consider When Connecting to the Cloud
The considerations in leveraging 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 the data transfer)
Security is often managed through the use of VPNs (Virtual Private Networks). This is an excellent solution for bi-directional communications and ad-hoc communications as it is set up for remote troubleshooting purposes. When using VPNs for ad hoc access, customers can leverage solutions to secure and broker access to endpoints in a very methodical and controlled way. This can include approval processes, windows of access and time limitations, and extra levels of authentication.
For information transfer to the cloud, it is becoming more popular to use publish-subscribe models, and connection brokers to maximize security. Remote sites will publish data to a known and very secure connection, and users of the data, cloud applications, will subscribe to the data through a broker, eliminating application knowledge of remote communication details that represent a vulnerability. Microsoft IoT Hub is an excellent example of this technology.
Industrial Protocols for Cloud Connectivity
Not all industrial protocols are compatible with cloud applications, nor should they be. Without getting into each protocol and defining if it can be connected to a cloud, it will suffice to say that an overall solution to the connectivity issue will be to deploy an edge device technology that will handle the communications to your IT and OT environment on one side and the requirements for cloud data transfer on the other. These devices are beginning to proliferate in the market, some with specific cloud connectivity built in, and others with more of a toolkit approach, which can be flexible in their configuration. Most are designed with data transfer as their only function while others support data modeling, analytics, and visualization, in addition to data transfer.
From an OT perspective, we are again talking about a myriad of protocols and the purpose they have been defined for. And as mentioned before, some networks are designed for deterministic performance, for example, the communications between a PLC and a SERVO Drive. Protocols such as these are difficult to share without impacting their performance. Data sharing will be accomplished by communicating with the controller, not devices on a control network. Other, more general-purpose protocols are often easily connected to a cloud gateway (edge device) in order to share information with the cloud.
Ethernet has been improved significantly over time, both in topology and performance, initially being focused on coax and now over twisted pair and delivering speeds over 1 gigabit. A more recent enhancement is in the area of device synchronization and the ability to shape traffic. These features, and more, fall into an area of Ethernet enhancement called TSN (Time Sensitive Networking). TSN delivers the ability to prioritize communications on Ethernet and also control the bandwidth of traffic. The overall benefits in the long term are a greater ability to troubleshoot – with access to all devices, a reduction in costs – through simplified architectures and the ability to expose all information to cloud systems.
Connecting Safely and Securely
Even with the breadth of industrial protocols on the market, it is now possible to connect virtually any automaton solution to the cloud, safely and securely, either directly or using edge gateways. The challenges we face today are in the area of education and justification, but the benefits are many.
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