1. 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

2. 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.

3. 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

4. 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

5. 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.

6. 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”.

7. 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.

8. 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

9. 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

10. 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

11. 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.