Introduction

Network variables are any variables that are cyclically exchanged between PC/CX1000 via TwinCAT. Variables with any data types, including complex types, can be exchanged. The Publisher/Subscriber model is used. For highly deterministic communication, the real-time Ethernet driver for TwinCAT must be installed.

Publisher/Subscriber model

In the Publisher/Subscriber model, the Publisher makes variables available. Subscribers can subscribe to a variable. The Publisher can make the variable available to a Subscriber, several Subscribers or all Subscribers. In Broadcast mode the variable is made available to all PCs, in Multicast mode to selected PCs and in Unicast mode only to one selected PC. A Subscriber can also be Publisher at the same time. In this way, a bidirectional data link can be provided.