Using DNP3 in a contemporary SCADA system is an easy decision. DNP3 is a standard protocol that has wide acceptance in the industry and is flexible enough for almost any application. DNP3 certainly has its place in an effective monitoring solution, but this doesn't mean that any off-theshelf DNP3 Master or Remote will be a best fit for you.
Before you commit to a SCADA monitoring solution for either your operating center or your remote sites, you need to consider a multitude of factors.
Before you buy... check for these 8 important features:
Masters sometimes present data in such an attractive, graphical interface that you can't see the forest for the trees. Make sure that you have access to a list view that provides a good presentation of event and alarm detail for more than a single site or region. Sometimes, summary graphical presentation can make detail an inconvenient click or two away when a decision needs to be made.
If you will be relying on Unsolicited Messages in your system, make sure there is a clear event for each alarm. Creating this association can involve expensive custom development on your Master system.
Avoid the allure of maintaining only an event log of newly reported Unsolicited Messages and a history log of acknowledged Unsolicited Messages. If an Unsolicited Message represents an alarm condition, there should be continuing visibility to the alarm even if the Unsolicited Message is acknowledged. Imagine what might happen to your network if a system operator acknowledges an alarm message, and then, for whatever reason, fails to correct the alarm condition. Who would know the alarm is still standing?
Masters should support organizing alarms by a wide variety of characteristics. Location, equipment type and severity are just a few possibilities that may make sense for organizing your alarms. The same alarm should be able to be posted to multiple categories. The presentation of sorted and filtered alarms should depend on the user logged on; the team responsible for generator maintenance doesn't need to wade through lists looking for generator events and alarms.
Make sure your master support the advanced features necessary for premium status monitoring, such as notification escalation, nuisance alarm silencing, automatic control relay operation, and automatic notifications by e-mail, text or pager.
If you're like most companies, you have a variety of equipment of different ages and technologies. Integrating this diversity into a SCADA Master can sometimes involve surprisingly expensive customization or additional modules. It is always difficult and uncomfortable to justify significant development costs after purchasing an already expensive SCADA Master. Why take the time, trouble, and expense to recreate capabilities that are already present in a high-quality, multi-protocol Master that is DNP3-capable?
If your remote is powered from a single source, then your critical monitoring is vulnerable to a single event. Losing that single source of power effectively compromises the continuous monitoring of your revenue generating equipment. If your installation does not have dual power sources, make sure the equipment is compatible with an external uninterruptable power supply. Also insure that the primary power is one of the points monitored at each location.
If a network failure compromises the collection of data, your remote equipment should provide for local visibility. Turn the worst case of having to dispatch techs to critical remote sites into a much better case by insuring that they will be able to browse to your remote units and have local SCADA until the network is restored.