How Are Devices Connected in the IIoT?
Industrial Internet of Things (IIoT) architectures arise from a mesh of smart sensors, software platforms, on-premise systems, and cloud servers. Despite such considerable interconnections, a noticeable gap still exists between the operational technology (OT) and information technology (IT) parts of the IIoT system.
IIoT can be difficult to implement with traditional automation strategies, requiring programmable logic controllers (PLCs), custom programming, and other expensive middleware to communicate data among field devices, cloud services, and control systems. Classical industrial automation architectures generally solve data processing from a hierarchical standpoint of data origin, storage, refining, and delivery. The difficulty with these architectures is the amount of work it takes to design, physically connect, configure, digitally map, communicate, and maintain field data points. For example, the following illustration (Figure 1) shows a traditional method of acquiring temperature data from a facility.
Figure 1: Traditional data acquisition methods require configuring and maintaining many layers in a hierarchy of hardware and software.
Image Source: Opto22
Instead, modern industrial automation systems use distributed I/O systems, networked processors, and secure devices. Sensors and other edge devices are becoming increasingly more capable, with PC-like processing and communications abilities. The architecture is evolving towards being more scalable and distributed, capable of skipping the layers sandwiched between the real world and intermediate or top-level analytics systems.
Vendors are taking advantage of these new technologies to make distributed I/O systems more configurable and autonomous. The availability of sufficient computing power enables all necessary communications software to be directly embedded in an I/O device. The following image (Figure 2) illustrates the same data acquisition scenario for temperature acquisition. In this scenario, a low-level edge I/O device is capable of sending data directly to its destination, replacing several layers.
Figure 2: Modern edge devices flatten and simplify the architecture. Image Source: Opto22
How Does Edge I/O Simplify IIoT Connections?
Although many smart wireless sensing devices have begun appearing at the edge, the majority of I/O switches, sensors, and transmitters use wired connections. Traditional remote I/O requires an industrial controller or gateway to propagate these signals to other systems, limiting their availability to enterprise consumers. Edge I/O avoids this complexity. It can be installed and operated independently, using embedded IIoT tools and protocols to offload central processing, preserve data fidelity, improve data transfer efficiency to the cloud, and share data instantly across the organization.
An example of an edge I/O device is the groov RIO module from Opto 22. It is an intelligent, Ethernet-based I/O unit that supports a wide variety of software-configurable I/O options. It can quickly and directly connect traditional wired switches and sensors to Ethernet networks, software applications, and cloud platforms without intermediary control or communication hardware, such as PLCs, PACs, or PCs. PoE (Power over Ethernet) is also supported. The groov RIO can be used in systems that already employ other control systems or completely stand-alone devices. Let's take a deep dive into the groov RIO's features and understand more about this edge I/O device.
Let’s See How the groov RIO Works
Groov RIO is an edge I/O module, with functionality falling somewhere between intelligent Ethernet I/O and a micro RTU (Remote Terminal Unit). Its primary purpose is acquiring data from sensors and switches; however, it can also run standalone, executing its own programs and control loops, similar to a controller. While it can’t do everything a controller can do, the groov RIO has functionality that a traditional controller does not, such as providing mobile HMI and interacting with network services.
The groov RIO provides a means to configure a large number of I/O very quickly. It provides eight channels of software-configurable multifunction, multi-signal I/O, as well as two mechanical relays. One device supports over 200,000 unique I/O combinations. Because the groov RIO replaces numerous devices in a traditional I/O system, costs can be reduced, as well as the time required for design and maintenance.
Groov RIO supports PoE; devices can be simultaneously supplied with low-voltage power and network connectivity via Ethernet. Additionally, the groov RIO has built-in security features, such as configurable device firewall, TLS certificate management, and segmented network interfaces. Native support for MQTT/Sparkplug B and other IoT tools such as Node-RED are included, enabling users to transport data directly from the edge to any other part of the organization without the traditional intermediary steps. If more I/O is needed, multiple groov RIO units can be joined securely.
Figure 3: Opto 22 groov RIO Edge Controller
Controlling the groov RIO
Groov RIO's embedded software and protocol support enable the secure exchange of data between the OT and IT worlds (Figure 4). The module comes pre-loaded with an array of industry-standard software tools. Also included is groov Manage, a web-based software for configuring groov RIO’s I/O channels, security, and communications. Once installed, the groov RIO can be independently managed and configured through this browser-based tool.
Groov Manage eliminates the need for a master control unit, and it features support for standard enterprise network services like DNS, DHCP, and VPN to facilitate network connectivity. Embedded communication options include efficient data publishing with MQTT Sparkplug, advanced signal processing, data aggregation, and transactions with databases and web services, using the low-code Node-RED environment and runtime.
Figure 4: groov RIO Architecture. Image Source: Opto22
After first connecting the groov RIO to a power supply and network, it runs through a start-up sequence, which includes obtaining an IP address from the network DHCP server. After start-up, the Administrator account must be created. The user can then navigate through groov Manage on a computer or mobile device much the same way as one navigates through any other web application (Figure 5). Groov Manage acts as a command center for the groov RIO. Through groov Manage, users can:
- Configure I/O channels and features
- Manage and tune PID control loops (requires groov RIO firmware 3.0 or higher)
- View wiring diagrams and specifications for all signal types
- Set up security, including user accounts, optional LDAP user management (groov RIO firmware 3.0 or higher), device firewall, security certificates, VPN client, and more
- Enable MQTT communications
- Create data flow with the Node-RED editor and runtime
- Manage files stored on the device and/or the USB memory stick
Figure 5: groov Manage Web Browser Interface. Image Source: Opto22
What Have Engineers Done with the groov RIO?
The following is an example view (Figure 6) of an IIoT Architecture that provides MQTT messaging, zoning, conduits, VPN access, and much more using groov RIO. In the red zones (OT1-3), edge devices like groov RIO and Opto 22’s edge programmable industrial controller, groov EPIC, connect to sensors, machinery, processes, legacy PLCs, and other assets in the field and isolate them from outside networks. The groov EPIC and groov RIO provide networking, control, monitoring, and security. Here, the groov RIO functions as an I/O manager getting its control instructions from a groov EPIC as independent edge I/O.
Figure 6: groov EPIC and groov RIO Architecture Demo. Image Source: Opto22
A secure connection to on-premise resources and/or cloud servers (DMZ) is established to access databases, MQTT brokers, VPN servers, and more. MQTT messages are then published from devices in the OT zones through the IT zones, allowing lightweight, bi-directional communication over secure, encrypted connections. SCADA systems are further connected to an MQTT broker in the DMZ or cloud as MQTT subscribers.
This system can be scaled to collect more OT zone data using additional edge devices. This architecture further supports remote access using OpenVPN. Note that while the groov RIO is frequently used as remote I/O in conjunction with the groov EPIC or another control system, it can operate autonomously, facilitating a direct connection between I/O signals and databases, business software, or cloud IoT platforms without the need for an additional controller.
The following are case studies of using the groov RIO from early adopters and technology partners:
Case Study #1: Granular Temperature Monitoring for an Automated Storage and Retrieval System (ASRS)
One system integrator was tasked with designing an automated system that collects temperature data from many points across a warehouse. The data is then directly fed into the customer’s Ignition SCADA system using MQTT. This monitoring system enables the proper storage of heat-sensitive items.
The traditional approach would have required installing and configuring PLCs and their I/O cards, along with power supplies and networking equipment in each location, and then programming the PLCs to perform the necessary functions. Additional gateways may have been required to support MQTT.
The simpler solution was to use groov RIO modules configured for temperature sensing. PoE supplied power to connected devices, eliminating the need for external power supplies.
Case Study #2: Remote Monitoring System
An OEM manufacturer required a remote monitoring system to support an equipment-as-a-service business model; however, the primary PLC they were using was not capable of remote communication. Initially, a completely new monitoring system was designed around an end-to-end IoT solution with proprietary wireless sensors and a private cloud storage backend. Its performance, however, was not ideal and the private storage was not accessible to other systems.
Their second attempt involved connecting a groov RIO module to the equipment’s existing I/O in parallel, with the connections going to the existing PLC. The groov RIO was connected to a 4G LTE modem, and a Node-RED program was created to push data to a MongoDB database. Groov RIO enabled the existing system to report data to a database backend without any modifications. This data populates the dashboards used by customers to monitor the system and issue invoices.
Final Thoughts: Connecting the IIoT
The goal of the IIoT is a simpler process of gathering and communicating real-world signal data. The traditional methods of connecting a system of field devices with IT systems are complex and require large numbers of additional devices. The groov RIO simplifies things; it provides compact and secure edge I/O that is tailored to communicating field data in IIoT applications.
The groov RIO can be configured to connect and power a wide variety of sensors, and communicate collected data to on-premise or cloud-based IT systems and software via Ethernet. While technically not a PLC, the groov RIO has the functionality and security to run as a standalone unit controlling a system of devices.