Glossary

Abbreviation/Term

Meaning

DCS

Distributed control system

DataAssembly

This is an MTP-specific term which means the set of data that describes the physical or virtual entity represented by a control, i.e., pumps, vessels, valves, PID controllers, etc.

FB

Function block

HMI

Human machine interface

JS

JavaScript programming language

MTP

Module Type Package

OS

Operating system

P&ID

Piping & instrumentation diagram

PC

Personal computer

PID

Proportional integral derivative

PLC

Programmable logic controller

POL

Process orchestration layer

SCADA

Supervisory control and data acquisition

Symbol

In TwinCAT HMI, a Symbol is an addressable data point exposed by the HMI server. Most commonly this is a PLC variable exported via the TMC, but it can also be a dynamic or internal Symbol. See the Terminology chapter for more detailed information. A Symbol is functionally analogous to a SCADA tag.

SymbolExpression

A representation of Symbol as a string, for example:

%s%ADS.PLC1.GVL_MTP.V03%/s% or %s%ADS.PLC1.GVL_MTP.V03::TagName%/s%

See the Terminology chapter for detailed information

SymbolPath

A representation of a Symbol as a path, for example:

ADS.PLC1.GVL_MTP.V03

See the Terminology chapter for detailed information

TMC

TMC (symbol file) is an XML-based symbol table generated from the PLC project. It defines which PLC variables (names, data types, attributes) are published by the TwinCAT runtime and thus become addressable symbols for clients such as the TwinCAT HMI server (ADS/OPC UA).

UserControl

User control element in the TwinCAT HMI Engineering, which is represented by files with *.usercontrol and *.usercontrol.json extensions

VDI

Verein Deutscher Ingenieure (English: Association of German Engineers)