AI in OT glossary
The words you will hear when AI meets PLCs and SCADA, explained in one or two sentences.
Short answer
AI in OT combines two vocabularies: AI terms such as agents and the Model Context Protocol (MCP), and automation terms such as PLC, SCADA, historian, OPC UA and UDT. This glossary defines both in plain language, with links to our practical guides.
Short definitions of the terms that come up when you bring AI into a plant. Each one links to a guide where it matters.
- AI agent
- An AI model that can take steps on its own using tools, for example read a trend, search a manual and draft a work order. In OT, agents should be read-only by default and every action logged.
- Alarm rationalisation
- Reviewing every alarm for purpose, priority and response, to reduce alarm floods. A migration is a good moment to do it.
- CMMS
- Computerised maintenance management system: the software that holds work orders, assets and maintenance history.
- Cross-reference
- A list of where a tag or block is used across the PLC program and SCADA. Essential before any change.
- E&I
- Electrical and instrumentation: the design and installation of power, control panels, field instruments and cabling.
- F-blocks (fail-safe blocks)
- Siemens safety program blocks for SIMATIC F-CPUs. Safety code is not something to generate with AI.
- FAT and SAT
- Factory acceptance test (before shipping) and site acceptance test (after installation).
- Historian
- A database that stores process values over time, used for trends and analysis.
- HMI
- Human-machine interface: the screen operators use to run a machine or line.
- Ignition
- A SCADA and IIoT platform from Inductive Automation, licensed per server with unlimited clients, tags and projects. Perspective is its web and mobile visualisation module; Vision is its desktop client.
- MCP (Model Context Protocol)
- An open standard, introduced by Anthropic in November 2024, for connecting AI assistants to tools and data through defined, logged actions.
- OPC UA
- The standard for exchanging data between industrial systems, from controllers to SCADA and IT.
- OT (operational technology)
- The hardware and software that monitor and control physical processes: PLCs, SCADA, drives, instruments and their networks.
- PLC
- Programmable logic controller: the industrial computer that runs a machine or process, for example a Siemens SIMATIC S7-1500.
- S7-PLCSIM Advanced
- Siemens software that simulates S7-1500 controllers on a PC, used to test PLC programs before they reach real hardware.
- SCADA
- Supervisory control and data acquisition: the system that gives operators an overview of a plant, with screens, alarms and history.
- SCL
- Structured Control Language: the Siemens implementation of IEC 61131-3 Structured Text, the PLC language AI models write best.
- TIA Portal
- Siemens Totally Integrated Automation Portal: the engineering software for SIMATIC PLCs, HMIs and drives. TIA Portal Openness is its programming interface.
- UDT
- User-defined type: a reusable structure of tags (for example a motor or valve) in Ignition or in a PLC.
- WinCC
- Siemens SCADA software. WinCC V7 and V8 are the classic versions; WinCC Unified is the web-based version engineered in TIA Portal.
Related guides: connect AI to PLC and SCADA data, AI for PLC programming, WinCC to Ignition.
Sources
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2800 Mechelen, Belgium E-mail: info@simsolutions.be Enterprise no. / VAT: BE 0680.932.773