Design World
By Rachael Pasini | May 15, 2026
A right-sized automation platform using open configuration techniques helped a user monitor a solar power system and improve return on investment.
Bruce Cloutier, Integ Process Group
Solar energy has bathed our planet for eons, and yet the ability to harness the Sun’s power as a renewable energy source is only a very recent development. The conversion of sunlight into electricity using ever-improving photovoltaic (PV) technologies has now become commonplace, enabling many to overcome complete dependence on the electrical utility company. A real-time monitoring system can help users optimize the value of their investment, but only if it avoids contributing significantly to the cost.
Various types of edge controllers are becoming available with the promise of delivering economical and flexible monitoring options. Typical solar PV system providers offer some level of monitoring with their own equipment, but these siloed views fail to provide a complete picture of system performance or energy flow. Obtaining real-time, instantaneous, and cumulative energy generation and usage status is key to visualizing reality and achieving results.
For users on a budget who still demand an improved level of sophistication, an independent programmable digital platform for monitoring is needed. A simple, compact, and capable automation controller can provide just the right degree of supervisory control and data acquisition (SCADA) functionality, without the lock-in and overhead costs of traditional systems.
Solar PV installations include certain basic features. The PV panels themselves can be installed in arrays or groupings that are ground-based or mounted on top of structures. Location decisions are often driven by the available real estate and the orientation of candidate buildings. PV panels are connected to inverters, whose purpose is to produce electricity compatible with the power grid (Figure 1). Batteries may be included to provide energy storage for use when weather impacts solar output, at night when generation ceases, or during grid outages.
Figure 1: Typical solar installations may include arrays of solar panels installed on the ground or other structures, typically connected to inverters, which create grid-compatible electricity.
While there may be a separate means to monitor each inverter and battery system through a mobile app or web-based interface, there is likely no all-encompassing record of power generation or power use by the facility. Overall status of supply and consumption, both onsite and in relation to the utility, is needed to truly track energy independence. Real-time information is a necessity for understanding the flow of power and for getting the most benefit from the solar PV system. A secondary and often overlooked consideration is using available information to confirm that all elements are always working to their best potential.
At one site, the user had installed each of the noted solar power elements, in each case choosing the preferred products and vendors to fit the need. The ground-based solar panels supply electricity directly to the grid, while the rooftop panels were integrated with a battery system providing backup power to the residence (Figure 2).
Figure 2: This diagram depicts 36 kW of grid-connected solar, 11 kW of rooftop solar supplying a battery backup system, and their interconnection with the facility and the utility. A SCADA system was developed to monitor overall operations.
Once the system was completed, the components worked as intended, but there was no single interface to evaluate overall performance at any given moment. This end user was aware that a custom SCADA system could do the job, but was unwilling to foot the development and ongoing licensing costs for such an endeavor.
Seeking a simpler SCADA solution, the first step was to evaluate available connectivity. The inverters for the ground-mounted array were found to support the MODBUS TCP protocol over Ethernet and so could supply data via the network.
The battery backup system is a closed design offering no data communications without additional ongoing expense, and would only provide information via a mobile app. To overcome this form of vendor lockout, inexpensive power meters with digital communications were installed on both the output of the system and the facility load side, measuring how much power was provided by the battery backup system and how much was consumed by the facility itself.
While a power utility’s meter can only be electronically read by the power company, the power readings from the inverters and the added meters are sufficient to calculate the flow of power either imported from or exported to the grid. One other grid status point is needed. When the grid goes down, the battery backup system isolates the facility to seamlessly supply site power. At that point, it is not possible to determine the grid status simply from the power meter readings, so a simple line voltage monitor is connected on the grid side. This measures voltages across all phases at the grid and provides a dry-contact signal if low voltage indicates an outage.
The SCADA system for this solar installation needed to provide visualization of real-time status and be able to historically trend data for all elements. The most flexible way to display data would be achieved by using a platform able to serve up dynamic internet-accessible web pages. This platform would also need to connect to the various data sources and preprocess the information to be presented in a web page format.
For a local interface, a simple stacklight would be sufficient to provide the following at-a-glance indications:
While consumer-grade single board computers (SBCs), such as Arduinos and Raspberry Pi’s, appear to be an economical option for a SCADA platform, the reality is that creating a robust, reliable, and maintainable system based upon those products is technically challenging and lacking in technical support. Furthermore, these types of products would not carry standard industry safety certifications, resulting in possible building code concerns.
Another option would be to install an industrial-grade programmable logic controller (PLC) or edge controller, with a comparatively large hardware cost. Each of those solutions would require different types of programming and configuration skills. Many brands charge for software development environments and then require licensing on a continuing annual basis.
Facing these choices, it became apparent that a more straightforward and robust all-in-one device based on familiar IT technologies would be a better approach. One suitable option for this role was found to be the JNIOR automation controller, offered by Integ Process Group (Figure 3).
Figure 3: The Integ JNIOR automation controller is a right-sized platform for combining essential visualization, automation, and connectivity functions, empowering users to enhance solar or other applications with digital capabilities and edge control, without unwanted effort and overhead.
The JNIOR is an easily configured and programmed SBC platform optimized for control and monitoring. It includes the on-board I/O, serial communications, and Ethernet connectivity needed for the project. It has industry safety certifications and accessible live-person technical support, all at a very reasonable one-time cost. The controller also features a purpose-built multi-tasking operating system (OS) for responsive control, supporting edge networking capabilities such as TLS/SSL for secure communications, and a full-featured web server supporting visualization.
For environmental protection and wiring convenience, the controller was mounted in an industrial wall-mount enclosure. Once connected to the site network, it was immediately reachable using a standard browser and served up a default WebUI. Hardwired I/O connections were easily established and tested through the WebUI. These included an input from the grid monitor relay and relay outputs to operate the stacklight modes.
Obtaining data from the four inverters servicing the ground-mounted arrays was the first real challenge. The controller supports MODBUS server and client applications, and it is supplied with an open-source subroutine that was readily adapted to read values from those inverters. A small application program was created to read data from all four inverters in a 15-second repeating control loop. Instantaneous information (including voltages, currents, and more) would be retrieved and simply stored in the controller registry, where it became available for viewing via the WebUI. The JNIOR even includes a built-in network sniffer to confirm proper ongoing communications with the inverters.
A second application program to query the two power meters over an RS-485 serial connection was created and verified, and a third program was established to track the status of the grid monitor and perform calculations based on the power readings written to the registry by the other applications. For example, the instantaneous power supplied by each inverter and the battery backup system are totalized, and the power used by the facility is subtracted to obtain the net amount of power being delivered to, or supplied by, the power grid. This routine provides the final information needed to complete the web interface, and it also operates the stacklight and beeper as needed.
The modular approach of implementing a few individual application programs, each handling the communications with a distinct subsystem, greatly simplified program development and testing. Because project development proceeded so smoothly, the scope of the SCADA project was (unsurprisingly) expanded. A second JNIOR was set up elsewhere at the facility to mirror the main controller’s I/O and provide the outputs needed for another stacklight station. A Linux-based server was added to collect the data from the JNIOR and store it long-term in an open-source MySQL database, which in turn supplies data for historical power plots. The second controller will be used to enable a conservation mode for prolonging runtime in the event of a utility failure and to automate other energy savings steps.
Obtaining and installing solar panels, inverters, and batteries represents a sizable cost. Only a small fraction of the solar power generated at this site is consumed by the facility. The result was a reduction of the facility’s monthly electric bill to $0.00, and the creation of a new revenue stream from exported energy — clearly demonstrating the value of full system visibility.
The ability to implement a streamlined SCADA platform using familiar and open configuration methods has provided a useful operational view at a low initial cost and with no recurring costs. A wealth of data is now available to support optimization efforts and is helping the end user get the most for the investment. These same right-sized, open SCADA techniques can be effectively applied to virtually any commercial or industrial automation project to deliver similar gains in visibility, flexibility, and cost efficiency.
Integ Process Group
jnior.com
Rachael Pasini is the editor-in-chief of Design World, covering industrial automation technologies, advanced materials, fluid power, additive manufacturing, and more. She also supports engineering leaders and managers in developing and sustaining innovative teams. Rachael holds a master’s degree in civil and environmental engineering and a bachelor’s degree in industrial and systems engineering from The Ohio State University. With nearly two decades of technical writing experience, along with trade journalism and teaching college math and physics, she is passionate about educating individuals and building supportive engineering communities.
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