Server-to-Agent Communication
The following picture shows the request/response telegram sequence between the MTConnect driver and the agent.
As the first step after startup, the server sends a Probe request to the agent to retrieve the agent's device and component configuration. For example: http://mtconnect.mazakcorp.com:5609/probe
The agent replies to the request with a Probe response telegram which contains the structure of its agents and their components and data items. The server uses this information to generate the OPC UA data model (name space) for this agent.
At the second step the server sends a Current request to the agent to retrieve the current values of all data items of the agent. For example: http://mtconnect.mazakcorp.com:5609/current
The agent replies to the request with a Current response telegram which contains the current values of all data items.
At the last step the server sends a Sample request to the agent. This Sample requests initiates the agent to cyclically send response telegrams whenever data items changes in value or state. For example: http://mtconnect.mazakcorp.com:5609/sample?interval=2000&count=1000&heartbeat=10000&from=3179164
The agent cyclically sends unsolicited Sample (response) telegrams. If no new data available for a time the server specifies in its Sample request telegram the agent sends a 'heartbeat' telegram to signalize to the server that it is still alive.