OT Glossary

In OT, this often means a device or software that connects and translates between different networks or protocols. For example, a protocol gateway might connect a Modbus device to a Profibus network, translating data so both sides understand. Or a gateway could link an isolated control network to a plant DMZ network (with tight security controls). Essentially, whenever two parts of the system that “speak different languages” need to communicate, a gateway is the intermediary that makes it possible (while ideally keeping things secure and compatible).

Generic object-oriented substation event protocol

A communication model part of the IEC 61850 standard (power systems). GOOSE messages are a mechanism for very fast, event-driven communication in electrical substations (for example, to trip breakers or signal alarms). They are multicast messages that can convey a change of state (like “Breaker open!”) with extremely low latency, replacing old hard-wired inter-relays. While this term is power-industry-specific, it’s good to know since modern substations now use GOOSE over Ethernet to react to faults in milliseconds.

Opposite of Brownfield. It describes a new project or facility built from scratch, on a metaphorical “green field” with no constraints from legacy equipment. A greenfield ICS deployment can design security and modern architectures in from the start (a luxury not always present in brownfield sites). For example, a brand-new factory with all new control systems and network infrastructure is a greenfield deployment, and the engineers have free rein to choose the latest technologies and best practices.

Highway addressable remote transducer

A protocol used in process industries that allows digital communication with instruments over the same wires as analog signals. Many analog field instruments (like pressure transmitters) use a 4-20 mA signal to indicate value, but with HART, they can also superimpose a digital signal on top of that current loop. This lets operators or control systems talk to the device, reading diagnostics, setting ranges, etc., without extra wiring. Think of HART as giving your “dumb” analog sensor a way to speak up and say more than just its measurement, all over the existing cable.

Hazard and operability study

A structured approach for examining a process or system to identify potential hazards and operability problems. In industrial contexts, a HAZOP is done by a team brainstorming “what if” scenarios for each part of a process (e.g. “What if valve X fails closed?”) to foresee what could go wrong. While HAZOP itself is a process safety technique (ensuring the process is designed safely), it’s increasingly being adapted to consider cybersecurity (e.g. what if a hacker did X). 

A specialized database system for time-series data in industrial environments. A historian continuously collects and stores chronological data from the process, things like temperatures, pressures, flow rates, equipment statuses, etc., often at high frequency. These databases are optimized for time-stamped data and for rapid retrieval of trends. They’re crucial for analysis, troubleshooting, and regulatory reporting in industrial operations.

Human machine interface - Visually represents the current state of a process, typically providing operators some way to interact with the process as well (change set points, open/close valves, start/top equipment...).

A decoy system or server set up to attract attackers, so their techniques can be studied. In OT, a honeypot might mimic a PLC or a SCADA server to lure in would-be intruders. Researchers deploy ICS honeypots that emulate vulnerable control systems to see how attackers behave when they think they’ve found an exposed power plant or factory. The honeypot has no real control over a process. It’s a trap, and any interaction with it is by definition suspicious, since legitimate users wouldn’t normally be there.

A major ICS vendor known for DCS and process control systems (Experion), as well as building automation. 

Industrial automation and control systems

Basically the same thing as ICS. It is the acronym formally used by the IEC 62443 standards to refer to the collection of personnel, hardware, software, and processes involved in controlling industrial automation.