5 Use cases ToC Previous Next

A vision system assesses situations automatically through machine vision and machine evaluation. This document describes how a vision system is addressed via OPC UA and integrated in a superordinate or a peer to peer structure. The description covers all aspects relevant for operation.

Interaction of the client with the vision system

A vision system usually has the role of an OPC UA server, i.e. its states are exposed via an OPC UA server. This is what in this specification is described and defined.

The client system can control the vision system via OPC UA. The vision system may also be controlled by a different entity through a different interface.

The vision system reports important events – such as evaluation results and error states – automatically to a subscribed client.

However, the client can query data from the vision system at any time.

State Machine

The state machine model is an abstraction of a machine vision system, which maps the possible operational states of the machine vision system to a state model with a fixed number of states.

Each interaction of the client system with the vision system depends on the current state of the model and also the state and capabilities of the underlying vision system.

State changes are initiated by method calls from the client system or triggered by internal or external events. They may also be triggered by a secondary interface. Each state change is communicated to the client system.

The state machine is described in more detail in Section 8.

Recipe Management

The properties, procedures and parameters that describe a machine vision task for the vision system are stored in a recipe.

Usually there are multiple usable recipes on a vision system.

This specification provides methods for activating, loading, and saving recipes.

Recipes are handled as binary objects. The interpretation of a recipe is not part of this specification.

For a detailed description of Recipe Management, please refer to B.1.

Result Transfer

The image processing results are transmitted to the client system asynchronously. This transmission includes information on product assignment, times, and statuses.

The detailed data format of a result is not included in this specification.

Error Management

There is an interface for error notification and interactive error management.

Previous Next