On-premises or cloud-based SCADA? Cyril Pinede explains how to make the right choice for your facility.
Intelligent sensors and automation equipment generate vast amounts of valuable operations data. If it is not managed correctly, this ‘big data’ can be overwhelming. The challenge is to present clear, actionable information to the right people at the right time, thereby improving their decision-making and helping to protect people, facilities and the environment. Helping to meet this challenge are modern supervisory control and data acquisition (SCADA) systems.
There are two main types of SCADA systems; on-premises and cloud-based, although some organisations choose to use both layered together. Before investing in either it is important to understand the differences and benefits of each.
On-premises SCADA system
SCADA systems were initially developed in the early 1970s to be a universal means of remote access to a variety of local control modules, which could be from different manufacturers and allowing access through standard automation protocols. Back then, SCADA still had a control system architecture comprised of computers, networked data communications, and graphical user interfaces used for high-level supervision of machines and processes.
Large SCADA systems have become very similar to distributed control systems in terms of their function, while providing multiple means of interfacing with a manufacturing plant or locally housed assets. SCADA systems are used widely in the upstream oil and gas sector, but also within other industrial applications, such as utilities, mining and many others. The technology has evolved and now includes a wide range of features aimed at improving efficiencies, increasing safety, and enabling better operational and business decisions.
The first generation of SCADA systems were independent, proprietary systems, with another mainframe acting as the back-up for connection to the remote terminal sites in case of failure. Advancements came through transforming the information and command processing from a central unit to a distributed network, where each station was responsible for a particular task. This improved resiliency and safety. However, there were no considerations given to security, long-term costs to maintain, or standardisation at that point. Subsequent iterations of SCADA systems focused on improving these aspects, using a ‘networked’ systems approach. This allowed SCADA to be spread across more than one local area network and separated geographically using a process control network (PCN).
Cloud-based SCADA
Today, the latest generation of SCADA is web or cloud-based, as opposed to the historical on-premises systems. The growth of the internet and industrial connectivity has led to implementing web-based technologies, allowing users to securely view data, exchange information, and control processes from anywhere in the world, at any time. Cloud-based systems use internet browsers as the graphical user interface for the operator’s HMI. This simplifies the site installation, reduces operating costs, and enables users to access the system from any device that is internet-connected, including mobile phones and tablets.
The biggest difference between on-premises versus cloud-based is where the software and data are located, and who is typically responsible for the security, performance, maintenance and control. On-premises SCADA houses the software and data at the plant or asset site, and the entire scope of the hardware, software and architecture is owned and managed by the operator. Cloud-based SCADA, on the other hand, runs off web-based applications, where its management, including updates and security, is generally handled by the SCADA provider, who also takes on ownership and operation of the hardware, servers and software.
It is important to note that even though cloud-based SCADA was developed after the on-premises type, both have their own advantages and disadvantages, and selection should be based on the application, scope and business strategy. It comes down to the level of control and ownership that is required, and where the assets are located.
Maintaining control of your own solution
For businesses that are keen to manage their own SCADA, an on-premises solution is likely to be very attractive. By owning the devices running the software and storing data, and having them physically within reach, a business can decide and act on their maintenance, security, upgrades and data storage prerogatives. Cybersecurity will be the sole responsibility of the operator, who may find comfort in the fact that their data lives on a server in their own office. However, the downside to having all that control is that you must maintain all the hardware, architecture and software, which if done poorly can translate to a much higher cost, risk and obsolescence. Typically, IT management is not the core value-adding function of an industrial business, and therefore many companies choose to forgo the additional expense of systems and people to maintain them and instead gravitate towards a cloud-based system.
Benefits of outsourcing
The biggest advantage of cloud-based SCADA is the outsourcing of all hardware, software and security ownership and management responsibilities. The cloud-based SCADA provider becomes responsible for keeping the system running 24/7 as well as handling all the maintenance, data back-ups and continual software improvements, without causing disruption to normal operations. A software-as-a-service (SaaS) model ensures the most up-to-date software, but the end user can focus on their main business, while reducing costs, personnel requirements and risk exposure. It is also worth noting that installing on-premises software on an organisation’s server, PCs and laptops, can be quite time-consuming. Cloud-based software, on the other hand, can be deployed over the internet in just hours.
Overall, on-premises SCADA is generally very conducive to businesses who have the resources and will to manage their systems and operate assets that are generally located in close proximity and of high sophistication, such as a refinery or power generation plant. Cloud-based systems are ideal for operators of multiple disparate, remotely located assets spread over large distances. For many emerging industries, such as sustainable hydrogen production and solar power generation, cloud-based SCADA is becoming essential. Typically, assets are quite small and dispersed and deploying SCADA systems at these sites is not possible because infrastructure such as data networks, servers and IT rooms, is not available.
Cloud-based SCADA is also ideal for businesses that would like to outsource their SCADA management functions to a trusted third-party that can always seamlessly deliver the latest version. This ensures continuous improvements to functionality and security, while giving operations the ability to easily scale the system with their business at a lower overhead cost.
Security comparison
Security is an essential consideration for any SCADA system. If you adopt an on-premises system, ideally you will have an entire team focused on security that are abreast of all most recent potential threats and viruses and have a resiliency plan in place. Large companies usually have security departments that can handle this very well. If that security expertise is not available in-house, then a solution such as Emerson’s Zedi SaaS SCADA is perhaps the better option. The Zedi IIoT (Industrial Internet of Things) platform was ‘born in the cloud’ meaning it was developed from the ground up within a cloud system and runs on Microsoft Azure. In terms of the data networks, the connections are encrypted and secured from the communication device back to the Zedi platform infrastructure through dedicated access point names and virtual private networks. To further safeguard data, real-time customer data back-ups are performed. Many organisations with remotely located assets leverage the Zedi platform to acquire data from any digital monitoring hardware. This provides their staff with advanced analytics and web interfaces then help to improve decision-making by presenting role-specific actionable data to the appropriate authorised users.
Cyril Pinede is with Emerson.