Implementing the Industrial IoT Data Flow

In the previous chapters, we looked at how a typical industrial scenario works and at the existing technologies that have been in place since 1990. In this chapter, we are going to understand how to connect this old world to the new IoT world. We will look closely at how to connect and gather industrial data from different devices and data sources. In particular, we will explain the OLE for Process Control (OPC) protocol in detail. We'll start by looking at its original implementation in 1996, based on the Microsoft architecture of Component Object Model (COM) and the Distributed Component Object Model (DCOM), and track its progress right up to the current Unified Architecture (UA), which is based on open and interoperability standards.

We will then go into detail about some concepts that were outlined in the previous chapters. These...

Discovering OPC

No other industrial communications standard has achieved such widespread acceptance across so many different verticals, industries, and equipment manufacturers as OPC Classic. It is used to interconnect a large variety of industrial and business systems. SCADA, Safety Instrumented Systems (SISs), Programmable Logic Controllers (PLCs), and Distributed Control Systems (DCSs) use OPC to exchange data with each other and with Historian databases, MES, and ERP systems in the corporate world. The reason for the success of OPC Classic is very simple—it is the only truly universal interface that can be used to communicate with different industrial devices and applications, regardless of the manufacturer, software, or protocols used in the control system. This ability has become increasingly important, as the need to exchange information between the different devices...

Understanding the I-IoT edge

The edge is the junction point between the industrial world and the IoT world in the cloud. The edge can be decomposed into three macro components, as shown in the following diagram:

The macro components of the edge

The Edge Gateway is the core and is responsible for forwarding the data from the site to the IoT Data Hub, whether this is on the cloud or not. The Edge Tools are utilities for configuration, log management, and patching the edge operating system, either from a remote or a local user interface. The Edge Computing is a new, upcoming component that uses data to perform an action at site level or to provide insights to headquarters.

So far, the Edge has been limited to collecting and forwarding data using the Edge Gateway to the I-IoT middleware, whether this is on the cloud or not. Recently, however, industrial companies have been able to...

Implementing the I-IoT data flow

In this section, we will discuss the I-IoT data flow. We will look at it first from the perspective of its architecture and network, and then move on to considering the strengths and weaknesses of each available data source option. So far in this book, we have not yet seen a situation in which industrial equipment is directly connected to the cloud. This is actually technically possible—there are several pieces of industrial equipment that have this ability, using internet protocols such as MQTT, CoAP, and AMQP. Examples of this kind of equipment include complex packaging systems, Automated Guided Vehicles (AGVs), robotized working cells, or the devices and equipment involved in a fully-automated warehouse. In this section, however, we are interested in industrial plants in which the factory floor is built and managed by thousands of sensors...

Summary

In this chapter, we learned how to implement the I-IoT data flow in a complex industrial plant. We started by looking at OPC, including what it is, how it has evolved, and how it works in both its implementations—OPC Classic and OPC UA. We explored how it connects to data sources to expose their data through common interfaces, following a common data model. We then went into detail about the edge, analyzing its features, internal components, architecture, interfaces, and current implementation.

After that, we started our journey on the I-IoT data flow. We looked at how to select a data source to connect to in order to gather data. We explored controllers, such as the PLC or the DCS, a SCADA system, and a Historian system. Each of these options has its own advantages and disadvantages; no one is better than the others. The choice must be made depending on the capabilities...

Questions

1. What is the main difference between OPC Classic and OPC UA?
   1. OPC Classic uses COM/DCOM, while OPC UA is platform-independent
   2. OPC Classic uses TCP, while OPC-UA uses HTTP
   3. OPC Classic does not have a data model, while OPC-UA does

2. What is the mechanism used by DCOM to send and receive information between COM components in a transparent way on the same network?
   1. Marshalling
   2. Remote Procedure Call
   3. Dynamic TCP ports

3. What is the main advantage of using OPC rather than the legacy industrial protocols of the device or equipment?
   1. OPC allows us to query for industrial data in the most efficient way
   2. OPC allows us to query for the industrial data by means of a Windows box
   3. OPC abstracts the connected device, providing standard and common interfaces to query its data

4. How can we secure the communication channel between an OPC UA client and an OPC UA server?
   1. If the security...

Further reading

Additional resources can be found at the following websites:

• Fog Computing versus Edge Computing: https://www.automationworld.com/fog-computing-vs-edge-computing-whats-difference
• Docker Edge: https://www.docker.com/solutions/docker-edge
• Forbes about Azure or AWS Edge: https://www.forbes.com/sites/janakirammsv/2018/07/01/5-reasons-why-azure-iot-edge-is-industrys-most-promising-edge-computing-platform/#3a5200233249
• OPC Foundation: https://opcfoundation.org/