# u-create glossary

## flow

In Node-RED, a flow is a connected subgraph of nodes with its own data sources and data sinks. Flows may be interconnected via indirect links.

## Function Block Diagram

Function Block Diagram (FBD) is a graphical programming language. A program is represented by directed networks. The elements represent function block instances, functions and variables. The connections represent the control flow.

## node

Nodes are the core elements in Node-RED. Nodes function as black boxes, that take in data as messages. These messages are transformed by the node and output again.

## Node-RED

Node-RED is a flow-based programming tool for transferring and manipulating data from devices, APIs or online services. With Node-RED, a program is represented as a directed graph. The nodes represent transformations. The connections represent the data flow.

## Program Organisation Unit (POU)

Program organisation units contain a defined portion of a program and provide a defined interface with inputs and outputs. Functions, functions blocks and programs are program organisation units.

## real-time application

The real-time application controls the devices connected to the controller and handles their process data in real-time. The real-time application is programmed in accordance with IEC 61131-3.

## u-link Remote Access Service

Quick remote access for simplified maintenance and increased availability of machines and systems.