A water treatment plant needs 14 operator stations across the site. The SCADA system already serves fully engineered HTML5 screens from a central server. Quoting 14 Windows-based panel PCs at $3,200 each plus Windows IoT LTSC licensing comes to roughly $52,000 just for visualization hardware. The same 14 stations as ARM-based web panels: $11,200 total. The screens look identical to the operator. The difference is $40,800 — and a decade of Windows patch management.
Web panels are not "cut-down" panel PCs. They are a different architecture for a different job. Confusing the two is how plants end up overpaying for visualization hardware they do not need.
What is a web panel, technically?
A web panel is an ARM or low-power x86 device running a dedicated browser engine — usually a Chromium-based kiosk client — on an embedded Linux or real-time kernel. It has no general-purpose operating system, no local application runtime, and no writable persistent storage beyond configuration. Its sole job is to render HTML5 content from a remote server: a SCADA web client, a dashboard URL, an Edge gateway's configuration page, or a machine builder's web-based HMI. It boots in 5–8 seconds, connects to the configured URL, and renders the page full-screen.
What defines a panel PC in the same form factor?
An industrial panel PC runs a full Windows 10/11 IoT or Linux desktop operating system on an x86 processor. It can execute local applications — a SCADA runtime, an OPC UA client, a .NET application, a SQL database — independent of any remote server. It has local storage (SSD), a full file system, user account management, and all the security surface area that comes with a general-purpose OS. Panel PCs are not displays; they are computers with a display attached.
When does a web panel make more sense than a panel PC?
Four conditions collectively make the web panel the right choice. First, the visualization content is already web-native — HTML5 SCADA screens, a Grafana dashboard, or a machine builder's Node-RED UI served over HTTP. Second, no local application logic is required at the operator station (all logic runs on the server). Third, the station count is high enough that OS license costs become material. Fourth, the operator station has no need to run standalone if the network is down — because if the server is unreachable, the machine is already stopped. When all four conditions hold, a panel PC adds cost without adding function.
When does a panel PC remain the correct choice?
The panel PC is required when any of four things are true. The visualization client is a native Windows application (FactoryTalk View SE, WinCC Runtime, iFIX Workspace) that cannot be served as HTML5. The station must run logic locally — a recipe manager, a local historian buffer, or an OPC UA client that aggregates data from controllers on an isolated machine network. The station must operate with degraded functionality during a network outage (local alarm logging, cached trend data). Or the site's cybersecurity policy mandates a domain-joined Windows endpoint with Group Policy management, antivirus, and centralized patching — a web panel cannot participate in Active Directory.
| Requirement | Web Panel | Panel PC |
|---|---|---|
| Renders HTML5/SCADA web client | Native function | Via browser (overhead) |
| Runs native Windows SCADA runtime | Cannot | Yes |
| Runs local OPC UA client | Typically no | Yes |
| OS license cost per unit | $0 (embedded Linux) | $90–$180 (Windows IoT) |
| Typical unit cost | $600–$1,400 | $2,200–$5,500 |
| Boot time to operational screen | 5–15 seconds | 40–120 seconds |
| Domain join / Group Policy | No | Yes |
| Offline (server-down) operation | No (by design) | Yes (local runtime) |
How do industrial web panels handle browser compatibility and kiosk lockdown?
A web panel's browser engine is qualified against a specific SCADA or dashboard platform — the manufacturer certifies compatibility with Ignition Perspective, Siemens WinCC Unified, GE CIMPLICITY Web, or equivalent. The browser is locked to kiosk mode: no address bar, no right-click context menu, no file download prompt, and a configurable whitelist of allowed URLs. If the browser process exits unexpectedly, a watchdog restarts it and reloads the configured page. These are not features a general-purpose panel PC provides out of the box — they require third-party kiosk software and additional configuration on a Windows machine.
The Emerson PACSystems RXi Web Panel is a Linux-based industrial touchscreen computer purpose-built for HTML5 visualization — a representative web panel architecture for SCADA and IIoT dashboard applications.
What about maintenance, updates, and cybersecurity?
A web panel has no user-installable software and no persistent user-writable storage. Its attack surface is the browser renderer, which updates as part of a signed firmware image — typically 1–2 updates per year versus the monthly Patch Tuesday cycle of Windows. There is no antivirus to install, no user accounts to manage, and no way for an operator to install unauthorized software. The security model is hardware-enforced: the device can only do what the firmware allows. This makes web panels attractive for sites where IT support is thin — a water or wastewater plant with one automation technician and no dedicated OT security staff.
Choose a web panel when the visualization content is already HTML5, the station count is high, and no local logic is needed. Choose a panel PC when the station must run native Windows SCADA software, operate offline, or comply with domain-joined endpoint management policies. The right question is not "which is better?" — it is "where does the runtime need to execute?"
