Device Setup

If a device supports multiple protocols, it should be set for the DNP 3.0 protocol.

Communications setup

The DNPR driver can use the RS-232, TCP, or UDP communication methods, using a standard COM port, digiboard, or Ethernet card. RS-232 communications can also be expanded through an adaptor. The type of adaptor used is determined by the DNP3 network Plant SCADA is interfacing with.

Plant SCADA operates on the presumption that a DNP 3 device will use RS-232 for communication. If you use the Communications Express Wizard to connect to a device, the following settings are used by default in your project.

These settings are recommendations only; your hardware may support other values. If you do set the baud rate, data bits, stop bits, or parity to another value, manually set the new value(s) in your project.

Note: DNP3 is a binary protocol, which means hardware flow control (not software flow control) should be used for serial connections.

A device should also be configured so that static data required by Plant SCADA is allocated to class 0. (For more information on classing data, see Data Acquisition within DNP3.)

Configuring Class 0 with points not required by Plant SCADA places an extra communication burden on the system during the regular integrity polling. Event data corresponding to the above-mentioned static data should be assigned to classes 1, 2, or 3.

The maximum request length for the DNPR protocol is 256 bytes.

See Also

The DNP 3.0 Protocol