DNP3 Overview What is DNP3? DNP3 Architecture Basics Where is it most often used? DNP3 Architecture Basics Events Polling Report by Exception Example: Waste Water Lift Station Tradeoffs Future of DNP3

What is DNP3? DNP3 stands for Distributed Network Protocol 3rd version. It came out of the Power Generation market and was based on serial devices originally. Its main use today is still in power generation, but has become widely utilized in water/waste water, transportation and oil & gas.

DNP3 Architecture The basic architecture of a DNP3 setup is Master / Outstation*, although that could include one:one and one:many configurations. The Red Lion RAM-XXXX family is a DNP3 outstation only, which MUST report to a DNP3 Master to work. *outstations are a/k/a “slave” devices

Basics - Events DNP3 uses “events” inside equipment set up to use this protocol How the events are used is based on how the driver is configured by the customer / OEM Events in our devices are stored in NVRAM However, they are NOT directly readable by an outside program like a text editor

Basics – Polling & Classes DNP3 has three polling levels and one integrity poll The 3 polling levels (classes) allow users to assign different levels of importance to various groups of data tags. The integrity poll is used to grab all data at one poll to be sure the unit is still active.

Basics – Report by Exception Report by exception is a feature many customers like and utilize. If set up in the unit, the DNP3 outstation device will proactively communicate to the master - versus waiting until the next poll – to report new information. This is also known as “unsolicited response”.

Example: Waste Water Lift Station The example will be a waste water lift station and how DNP3 would typically be set up in this situation. Setup Basics DNP3 uses Class 1, Class 2, and Class 3, for the different “classes” of tags. Each one can have different poll rates which is done by the DNP3 master.

Example: Waste Water Lift Station Class 1 Tags Typically alarms – need data back as fast as possible High level, pump overload trip, site entry, etc. Polling time ~ 1 min Class 2 Tags Conditional tags – could cause an issue, but isn’t cause for immediate shutdown Internal lights Polling time ~ 1-5 min

Example: Waste Water Lift Station Class 3 Tags Lower priority, non-critical information Flow totalization or pump runtime Polling time ~ 1 hr Integrity Poll Make sure the device is still alive Gather current status of all points listed in DNP3 database Report by Exception

Tradeoffs Disadvantages Advantages Setting up both polling classes and report by exception makes it possible to get highly reliable data AND be very conservative in the amount of data transmitted (lower cost to customer) In some real-world systems we’ve seen data transmission reduction by as much as 90% Report by exception data can be seen in some cases in less than 1 second. Critical events can be done using report by exception to get the absolute fastest update possible Disadvantages Not an easy protocol to set up Original configuration often requires help from RLC sales engineering or Tech Support Setting analog deadbands for analog input report by exception can be challenging

Future of DNP3 IEEE is currently working on DNP4 which includes high levels of encryption. DNP4 will also include various levels of outstation authentication. With Federal Gov. push to secure the “grid”, these features will be paramount. It will be critically important to get our driver up to DNP4 once the standard is released.