DNP3 PROTOCOL

Table of Contents

What is DNP3 protocol?

DNP3, or DNP 3.0, is a communications protocol used in SCADA and remote monitoring systems. It plays a crucial role in SCADA systems, where it is used by SCADA Master Stations (a.k.a. Control Centers), Remote Terminal Units (RTUs), and Intelligent Electronic Devices (IEDs)

It is widely used because it is an open standard protocol. This means that any manufacturer can develop DNP3 equipment that is compatible with other DNP3 equipment.

History of DNP3 Protocol

While IEC 60870-5 was still under development and had not been standardized, there was a need to create a standard that would allow interoperability between various vendors’ SCADA components for the electrical grid.

Thus, in 1993, GE-Harris Canada (formerly known as Westronic) used the partially completed IEC 60870-5 protocol specifications as the basis for an open and immediately implementable protocol that specifically catered to North American requirements.

The protocol is designed to allow reliable communications in the adverse environments that electric utility automation systems are subjected to, being specifically designed to overcome distortion induced by electromagnetic interference (EMI), aging components (their expected lifetimes may stretch into decades), and poor transmission media.

Features of DNP3

Output options
Secure configuration/file transfers
Addressing for over 65,000 devices on a single link
Time synchronization and time-stamped events
Broadcast messages
Data link and application layer confirmation

Working Principle of DNP3 Protocol

Frequently Asked Questions

➤ Difference between DNP3 vs MODBUS

Modbus is an application layer protocol whereas DNP3 consists of Application and Data Link Layers. Both protocols are used over many different types of transport, such as RS-232, RS-485, and TCP/IP. When it comes to TCP/IP, Modbus has a separate variant called Modbus TCP/IP but the DNP3 is wrapped within TCP/IP.

➤ What port is DNP3 Used

Note the default TCP port for DNP is 20000. Most DNP SCADA applications allow this to be changed when creating TCP socket connections.

➤ Is DNP3 is serial

Initially DNP3 used serial communications as IEC 60870-5-101, nowadays DNP3 allow using TCP/IP or UDP/IP communications over IP networks to improve the system communication response time. DNP3 is a protocol based on numerical identification of the data objects.

Referance:

https://na.eventscloud.com/file_uploads/b68188f3ce5b22895a67b1afe5e51b6a_DNP3IntroductionHORS.PDF