As a leading industrial automation system and operations software provider, Siemens intends to standardize production processes and workflows to increase efficiency and reduce the engineering and operation efforts of our customers. For this, structured and networked data from IT systems as well as from OT systems are an important prerequisite.
The implementation of MQTT communication with with higher level IT systems (e.g. MES systems) is demonstrated in an application example (for both SCADA - WinCC Unified PC RT - and HMI - WinCC Unified Comfort Panel) .
The PLC sends information to WinCC Unified, which publishes MQTT messages to the broker. The communication partner subscribes to specific MQTT topics, receives and finally parses the published messages. Conversely, the communication partner can publish a JSON string to an MQTT topic which will be parsed by WinCC Unified and forwarded to HMI tags; the values of the HMI tags will be written into PLC tags.
Link to Application Example (SIOS)