The TwinCAT IoT Communicator enables PLCs to communicate with mobile devices by connecting the PC-based TwinCAT controller directly and securely to a messaging service through TLS encryption. For smartphone and tablet users, the associated IoT Communicator app ensures that process data can be represented on all mobile devices in a clear overview. Alarms are sent to the device as push messages. Data is exchanged using a publish/subscribe mechanism. Because no special firewall settings are needed, integration into an existing IT network is easy. Information is exchanged via a message broker that uses the standardized MQTT protocol and acts as a central messaging service in a cloud or local network.