Supervisory Control and Data Acquisition (SCADA) platforms are the systems that control and manage much of society’s most important infrastructure.
As a platform, however, they were initially developed and optimized for controlling ‘inside the fence’ applications — monitoring processes that take place within the physical confines of, say, a power plant. In such setups, equipment and the systems used to control them are either colocated or situation within short reach of one another.
Connecting SCADA platforms with remote, beyond-the-fence sensors involves overcoming the inherent difficulties involved in provisioning reliable sources of power and network connectivity that allow remote devices to remain operational for long periods without human intervention.
While this poses a challenge for operators, it is by no means an insurmountable one.
SCADA’s Value for Operators
In the Industrial Internet of Things (IIoT), SCADA systems are the vital platforms used for monitoring and parsing data collected from sensors, fusing information sources, and automating the industrial processes that they monitor. And the more dispersed the assets that they control, the more vital such systems become.
SCADA systems have been around for decades, proving their worth in manufacturing plants, oil refineries, and other environments where the cyber-secure transmission of data between sensors and industrial control systems is crucial for the successful operation of utilities. Although operators have historically sought to integrate a small number of remote, ‘outside the fence’ assets with the systems, these have not traditionally been integrated into the SCADA platforms themselves due to the technical difficulty of doing so.
SCADA systems also provide operators with additional benefits such as increased information throughput, safety risk mitigation, reduced system downtime, and analytic abilities that include the ability to extract insights that aid in the creation of long-term value for the utility. The systems also offer stability and reliability that is unmatched by competing industrial control solutions.
New Applications Face Significant Challenges
In the push to expand the Internet of Things (IoT) to the industrial sphere, SCADA is rapidly being connected with outside-the-fence assets. This is particularly true in the fields of water, wastewater, electricity, and natural gas. The initial wave of adoption has brought to the fore challenges that operators in less physically complex networking scenarios simply do not have to confront.
When connecting to remote infrastructure, communications and power both place significant constraints on the viability of the monitoring program they are supporting. Unlike inside-the-fence sensors, which can simply be connected to a fixed power supply (which often also has a backup supply for redundancy), sensors located ‘in the wild’ enjoy no such luxury.
Such devices must either rely on batteries, which deplete and require periodic replacement, or use alternative power supply sources such as solar panels, which require regular maintenance to remain effective. In addition, being located beyond the physical limits of a secured location makes such devices substantially more vulnerable to vandalism and theft. This is particularly true when they are installed at street level within urban environments. This limitation is more difficult to overcome when more energy-intensive sensors need to be connected to the smart network. The more frequent the wireless data transmission cycle and the larger the packet size that needs to be transmitted, the greater the demand on the power source supplying electricity.
Connectivity poses a similar challenge.
While telecommunications operators may have strong coverage in some areas, it can be limited, or nonexistent, in others. Ensuring reliable connectivity throughout a smart network therefore entails system planners giving detailed consideration to the carriers available in each area it extends to. This can amount to a costly, time-consuming, and difficult undertaking for even the largest of utilities.
Networks developed specifically for the needs of the Internet of Things (IoT) offer an alternative means of ensuring connectivity for devices. Such networks include the low power wide area networks (LP-WAN) family that includes Sigfox and LoRa WAN as well as NarrowBand IoT (NB-IoT), a narrowband network developed within the mainstream, licensed spectrum familiar to everyone.
Impovements Are Required for SCADA and the IoT to Reach their Full Potential
Even for devices capable of connecting to both networks, however, the operating conditions are not yet ideal. Network coverage on the IoT-specific networks remains relatively limited. Tight bandwidth constraints also pose significant limits to the type, amount, and transmission frequency of data that can be transmitted over these networks.
The traditional breeds of networks (those based on GSM and CDMA) remain too power-intensive to enable fully-autonomous operation for long durations and with frequent transmission cycles. The future cellular-based IoT-optimized networks will offer significantly better power performance when they are rolled out, but the confusion over precisely which variant will dominate the market has created significant confusion and uncertainty on the part of operators planning future network deployments.
Those rigging inside-the-fence assets to SCADA systems do not face a problem in obtaining robust connectivity options. They have both complete visibility and autonomy whenever a component connected to a local area network (LAN) fails and – as the network operator – they can move swiftly to resolve any networking issues that may arise, thereby keeping downtime to a minimum.
Given the larger and more dispersed nature of their networks under management, outside-the-fence operators typically cannot meet the response times of those responsible for infrastructure that resides solely within centralized assets. If they cannot be troubleshooted from a distance, remote assets are also, naturally, significantly more costly to troubleshoot and repair.
Integrating SCADA systems with outside-the-fence assets involves significant challenges that merit serious consideration. Solutions to the well-known difficulties elucidated in this article, however, are being vigorously developed throughout the industry. Once these reach maturity, the full potential of remote monitoring will be self-evident to both operators and their consumers.
This blog was adapted from Values and Challenges of SCADA Systems for Outside-the-Fence Applications, an article originally published in IIoT World