SCADA stands for supervisory control and data acquisition. Behind the acronym is a simple idea: give the people who run a process one place where they can see what is happening and step in when something needs attention. A water utility uses it to watch pumping stations spread over a city. A food plant uses it to follow tanks, pasteurisers and filling lines. A building operator uses it to watch chillers and air handlers on every floor.
What a SCADA system does
Every SCADA system, old or new, does four jobs.
- Acquire data. It reads values from the field: levels, pressures, temperatures, flows, states of pumps and valves.
- Show the process. It draws process screens, often called mimics, where symbols for tanks, pumps and pipes show live values and states.
- Raise alarms. It compares values with limits and tells people when something is out of range.
- Send commands. It lets an operator start a pump, open a valve or change a set point, within the limits the engineers allow.
The word supervisory matters. SCADA sits above the local controllers that keep a process safe second by second. If the SCADA screen goes dark, the controllers and safety systems on site keep working. SCADA helps people supervise; it does not replace local control.
How it used to be built
For a long time a SCADA system meant a server in a control room, a set of workstations with a desktop client installed, and a project file maintained by an engineer who knew the tool well. Data came in from controllers over field networks. Screens were drawn in a desktop editor and deployed to each workstation.
That model works, and many plants still run it. But it has costs that grow over time:
- Every workstation needs the client installed and kept in step with the server.
- Seeing the process from another site, or from home during a night call, often means a remote desktop session.
- Each site tends to have its own project, so the same pump looks different in two places.
- Data lives in the SCADA system, while reports, dashboards and maintenance tools keep their own copies.
Why it moved to the browser
Three changes made browser-based SCADA practical.
Browsers can draw real process screens
Modern browsers render vector graphics and 3D scenes quickly. A process screen with hundreds of animated symbols updates smoothly on an ordinary laptop or tablet. There is nothing to install, and every user sees the same version of the screen.
Devices can talk to the cloud directly
Many sensors and gateways now speak protocols such as MQTT, LoRaWAN or HTTP. They can send data to a central platform without a local SCADA server in between. Where devices cannot reach the internet, a gateway on site collects their data and sends it up over one channel.
One platform can serve many sites
When the SCADA screens, the dashboards, the alarms and the device data live on one platform, the same symbol library and the same rules work across every site. A new site starts from a known template instead of a blank project.
What to look for in browser-based SCADA
Moving to the browser does not lower the bar. If you are evaluating a platform, ask these questions.
- Is the symbol library consistent? Operators read screens faster when every symbol follows the same visual rules.
- Do symbols show state, not just values? A pump that turns while running and a valve that shows its position are easier to read than numbers in boxes.
- Are commands controlled? Who may send a command, to which device, and is every command recorded?
- How are alarms handled? Look for severity, acknowledgement and escalation, not just a red light.
- How is data kept apart? If the platform serves several customers or business units, separation should be enforced in the database, not only in the user interface.
- Where is the data stored? Check which region your data lives in and whether it stays there.
How Hermetry approaches it
Hermetry builds SCADA into the same platform that connects devices and runs dashboards, rules and alarms. Screens are drawn in a SCADA designer in the browser, from a symbol library organised in industry packs. Every symbol exists in 2D and 3D, and 20 of them animate while the process runs. The same live values feed the screens, the dashboards and the rules that act on them.
Commands go through roles and are recorded in the audit log. Each customer's data is separated by row-level security in the database, and the platform runs in separate regions, so data stays where you put it.
Where to start
If you run a desktop SCADA system today, you do not need to replace it in one step. A common path is to start with one site or one line: connect a few devices, draw one screen, set up the alarms that matter, and compare the result with what operators use now. Read more on our SCADA page or browse the symbol library.