Near Real Time
MTConnect supports the ability to receive changes in near real time. The reference implementation of the MTConnect Agent written in C++ has this capability and has been validated to propagate changes from the adapter first reporting the even to the client application in between 3-10ms depending on the platform. For a reasonably recent computer with a CPU > 500Mhz the agent can easily handle a 5ms latency.
To request data with as little latency as possible, use the interval option and set the value to 0. This means to send data every 0 ms. The MTConnect standard specifies that if no data is available, then the agent will only need to send out a heartbeat every n seconds where n defaults to 10 seconds or can be set with the heartbeat option on the URL. So, the URL will look like this:
This will send data immediately when it arrives and send a heartbeat every second to the client. A heartbeat will allow the client to detect a disconnect or failure within 2x heartbeat ms; in this case you can detect a failure within 2 seconds. In this case we are defining failure as the agent fails and the client application can't detect the failure, such as the network was disconnected or the machine was powered off.