eScada integrates a profile-agnostic ONVIF event subscription client, which manages the complete lifecycle of a WS-Eventing PullPoint subscription with ONVIF-compliant devices.
Each received event notification is delivered as raw XML and pushed into a queue, where it can be processed asynchronously by a dedicated Lua module: all semantic interpretation is left entirely to the application. This design ensures compatibility with any current or future ONVIF profile (S, G, A, T, M, C, D), as well as with vendor-specific topic extensions.
Common types of ONVIF-compliant devices include: IP cameras, PTZ cameras, thermal cameras, access control devices, video analytics devices, audio devices, environmental sensors and multi-sensor cameras.
Topic strings, data item names, and the presence of optional fields such as temperature values or object identifiers are not mandated to be identical across manufacturers: devices must conform to the topic namespace structure defined in the ONVIF Event Service Specification, but may extend it with vendor-specific sub-topics. The raw XML preserved in each notification provides access to the complete original payload, allowing the application to handle both standard and vendor-specific fields.
The structure and content of ONVIF notifications are fully defined by the ONVIF specifications, the authoritative references for topic hierarchies, data item names, property operations and the WS-Eventing protocol. All specifications are available at www.onvif.org.