Connectivity

The interface connects to RTU field devices via TCP/IP, RS-232, or RS-485 directly. Moreover, the interface is capable of simultaneously connecting to several hundred field devices that communicate using DNP 3. Exact numbers vary depending on scan frequency and point count. OSIsoft has conducted field tests connecting nearly 400 devices and scanning the devices once a minute for 40 values without issue.

The PI DNP3 interface uses a multi-threaded Window I/O Completion Port model for communicating with DNP3 devices. This means that the interface does not wait for a response from a request to a given RTU before sending a request to another RTU. The result is a much more efficient interface that can communicate with many RTUs without affecting performance of the main interface loop, which processes data from all connected RTUs and updates the PI server.