Industrial edge visualisation and control implementations are far more manageable, flexible, and reliable when built on thin client and virtualisation architectures.
By Jason Andersen, Vice President, Business Line Management at Stratus
Industrial manufacturers understand that holding steady is rarely an option. This is because ongoing productivity improvements are a near-universal requirement. Such improvements can be realised in many ways, with the most valuable upgrades enhancing several things simultaneously, perhaps across multiple levels of an organisation. Today’s automation experts are discovering that moving visualisation and control functionality towards the industrial “edge” is helping them achieve better operations and improved maintainability, among other benefits.
Production and manufacturing industries have long employed supervisory control and data acquisition (SCADA) applications, human-machine interface (HMI) software and other automation platforms like programmable logic controllers (PLCs) and process automation controllers (PACs). Progressive use of these systems reduce waste, increase uptime and improve overall equipment effectiveness (OEE).
These systems require some level of “core” server and PC computing power to function, combined with local “edge” computing elements in the field to support visualisation and control. With the right pieces in place, maximum value is realised. Data from smart field systems has a reliable path to flow up to the core, while operators can access the key information required to run the factory in the best possible manner (Figure 1).
Standard commercial solutions have often been used to achieve these industrial computing goals. However, a better way is to use redundant hardware and thin client software options optimised for industrial applications. These products help users scale and locate their automation elements anywhere they want with flexibility and high reliability. This article examines why it’s compelling to use thin clients at the industrial edge for improving visualisation and control.
The Industrial Edge is not an Isolated Case
Visualisation and control computing at the industrial edge is applicable and beneficial to almost all operations. Most edge-located systems, devices and industrial internet of things (IIoT) sensors have become “smarter” and able to provide extensive data. Improved SCADA and HMI connectivity at the field enables access to this data.
Plants and processes can operate more efficiently when more HMI functions are deployed on the production floor, at field locations or wherever operators need them. This includes basic process monitoring and control, where operators need an immediate real-time picture of production that is accurate and comprehensive, along with the ability to make adjustments and changes. But it also involves providing visibility into more detailed analytics performed on the big data obtained from field devices. Accessing analytics reveals longer term trends that may not be addressed by direct observation of real-time data, but which can be acted upon by informed operators to improve efficiency.
In addition to operational improvements, other stages of the project lifecycle can take advantage of the industrial edge. During design and development, proven edge computing architectures offer a structure that can be reused from project to project, leading to design efficiency. The modular nature of edge computing concepts means OEMs and system integrators (SIs) can perform programming and testing development work on an in-house development platform, and then quickly deploy the results to new and existing field production systems. Fast HMI deployments and mobile capabilities make it far easier to commission new systems, and to update existing ones.
Ongoing maintenance is simplified by reliable thin client devices, which are rapidly replaced and re-deployed if necessary. As with commissioning, the ability to deploy mobile visualisation and computing clients on laptops or tablets provides maintenance crews with more options for troubleshooting problems.
Who Owns Industrial Edge Computing?
At this point, it is relevant to examine who owns the industrial automation computing structure, and how that definition concerns industrial edge and thin client rollouts.
Traditional industrial computing solutions have been heavily based on commercial information technology (IT) infrastructure, and rightly so. Many computing technologies used in industrial applications have trickled down from the commercial world including PCs, servers, Ethernet wired and Wi-Fi networking, virtual machines (VMs), thin clients and certain redundancy schemes.
However, manufacturing and process industries are built around the always-on world of operational technology (OT). This OT area requires much of the computing infrastructure described above but adds mission-specific hardware, software and communications methods. This includes PLCs, HMIs, smart instrumentation and industrial Ethernet protocols.
Converging IT and OT business units is not the end game, but industrial edge deployments must successfully coordinate both groups. Generally speaking, IT is not trained to work with industrial-specific products. In fact, the industrial network usually must be carefully firewalled from the business network. OT depends on VM and thin client technologies but is often not equipped to manage extensive IT-centric systems.
A workable middle ground is to package IT-centric hardware and software deployment capabilities into OT-focused platforms. In this way, IT technologies can be readily operated and maintained by OT personnel.
Thin Clients Help the Edge and the Core
Traditional automation computing architectures have included both distributed and centralised elements. Purely OT devices, such as PLCs and PACs, have been installed out at the industrial edge to interact with field devices like motors, valves and sensors for gathering information and performing detailed control. These OT assets continue to become more capable and still play an important role.
Crossing over into the IT realm, industrial automation SCADA and HMI servers formed a “core” above the OT devices, networked to desktop PCs situated throughout the facility as needed. While this IT-centric server and PC arrangement is functional, this configuration can be cumbersome to manage since it is relatively expensive to deploy and maintain numerous remote PCs. And now, the growing trend to install control and visualisation computing assets out on the factory floor, or even on skids and machines, makes this an even more complex proposition.
A better solution is to maintain centralised redundant server hardware at the core, but use it to host automation-related VMs, while serving up HMI applications to remote thin clients as needed. The servers can be located in a secure computer room or other protected yet remote locations like a control room or electrical room. Redundant servers can be traditional IT-centric style, or OT-optimised versions tailored for operating in an industrial role (Figure 2).
Thin client technology is the preferred way to reliably deploy and manage distributed HMIs and virtual machines throughout a facility, especially those systems supporting use of mobile device clients. This means any industrial automation VM or application can be viewed and operated at any PC, panel-mount terminal or mobile device connected to the company intranet.
This thin client architecture delivers a better experience at the edge and is far more maintainable by OT personnel responsible for the industrial automation core. Some benefits:
- Inexpensive edge:Edge-located thin clients are lightweight in terms of hardware resource requirements and relatively inexpensive, can be quickly replaced and re-configured.
- App serving flexibility:HMI applications can be served to any sort of remote device such as a PC, panel-mount terminal or even mobile devices.
- Easier development:Factory development and testing activities can be carried out on a VM environment hosted anywhere, actual field-deployed hardware is not required. This ability is very significant for OEMs and SIs.
- Rapid integration:Transferring development configurations to production system thin clients is convenient and quick, especially compared to configuring multiple standalone physical servers and PCs.
- Simplified maintenance:Centralised control of VMs is easier than maintaining widely distributed assets which would otherwise require in-person attention for updates and security patches.
- Scalable:Thin client architectures are readily scalable and benefit from centralised standardisation and re-use.
- Verified:Best practices can be established and maintained across deployed devices, for consistency, reliability, and repeatability.
The preceding benefits are only the basics realised by using standard thin client configurations. Just as the industrial hardware experience can be improved by using OT-optimised servers, so too can the thin client software experience. Thin client manager software optimised for industrial users is available (Figure 3) and adds the following enhanced thin client management features:
- Redundancy:VM sessions are redundant and can fail over on the server side to keep the thin clients up and running.
- Shadowing:Ability for administrators or terminals to view and/or operate another terminal.
- Session control:Combine and arrange multiple sessions on a single display.
- Role-based control:Control and manage what content is delivered based on login, certain users can view and control only what they are authorised to see and change.
- Locational control:Content can be tailored to the location of the thin client.
Next, let’s look at the architectural shift enabling thin client deployment.
Built for Operations
Traditional automation computing architectures commonly employ servers and PCs, while the improved configuration advocated here uses servers and thin clients. On the surface this doesn’t seem like such a drastic difference. However, the distinction is in where the computing is performed and how redundancy is carried out.
Classic architectures use servers to perform core supervisory computing services (VMs for SCADA I/O servers, historian, etc.), while remote PCs execute HMI functions and access the servers for I/O points. Reliability is based on dependable servers, redundant networks and multiple parallel PCs. Careful IT configuration could enable high availability and failover between server VMs, but these would be custom configurations.
On the other hand, thin client architectures centralise almost all computing on the servers, even the HMI functionality. VM sessions and HMI applications are delivered out to thin clients, with each acting as a window into functionality hosted on server VMs. But since the critical computing core is more centralised, it becomes more important to improve network and server redundancy.
As with classic architectures, the server VMs could be hosted on traditional hardware with customised high availability configurations, but a better option is to use industrial-specific servers with paired redundant nodes. These systems can load-share individual VMs between two nodes, or even assign a VM to one node or the other. In the rare event of any single hardware failure, this type of redundancy provides zero downtime.
Furthermore, using industrial-grade thin client manager software installed on these robust servers provides even greater reliability. OT-optimised servers and thin client software are complementary products that enhance each other to best deliver visualisation and control computing services at the industrial edge.
Conclusion
The nature of production and manufacturing industries with their emphasis on reliability means they usually are not employing cutting edge technologies to achieve automation. However, each time industry personnel move ahead on a new project, they are well positioned to survey the technological landscape and make good use of proven technologies. In order to improve productivity and OEE, end users have recognised a need to enable visualisation and control closer to the industrial edge.
SCADA and HMI visualisation have been fundamental elements of automation strategies for a long time, but now there are better ways to deploy these systems. Establishing an architecture of redundant servers supporting remote thin clients provides the familiar benefits of SCADA and HMI systems, while allowing them to be easily extended to any location since content can be delivered to any fixed or mobile device. Thin client architectures provide a modular way for OEMs and SIs to perform development, a rapid way to deploy the work to the field and a flexible means for operations and maintenance to own and operate these systems for the long haul.
This improved approach for delivering visualisation and control can be achieved by using customised commercial solutions and carefully coordinating the activities of IT and OT personnel. A better approach is to use mission-specific server hardware and thin client software products optimised for industrial applications—which can be more readily deployed, operated and maintained by OT personnel.
