Real Time Database Overview

The PICS real time database is a memory image of the most recently produced (scanned or computed) values for all of the points defined in the static database. A point's real time data record contains a date/time stamp indicating when the value was produced, status & quality information plus both the raw and engineering unit values. These records are managed by a diverse family of applications including:

RTDBA

The real time database agent. This program is responsible for primary distribution of PICS real time data to all nodes on the PICS network. It also makes the data available to client applications on the node. RTDBA replaces both the RTDB and RTRemote applications by only transmitting data provided locally to the network, and by sending only data received from the network (including data it may have sent) to local applications.

RTServer

The WAN real time data server. This program runs as a client application (to to any real time agent) on a PICS node and provides a direct (TCP) data stream including only the requested data points (to keep the bandwidth down and the security up) to machines running the real time WAN client.

RTClient

The WAN client real time agent. This program connects to RTServer and requests the minimal set of points necessary to satisfy the local machine's needs (as determined by combining all local real time data requests).

RtdbDDE

For customers wishing to use third party applications to process/display PICS real time data, we provide this program as a DDE interface to the PICS data stream. This program runs as a client of any real time agent (subscribing to all points available) and makes the data available to any application that supports a standard DDE interface, such as Microsoft Excel.

Others

A number of other modules have been created over time to serve special purposes. Some examples include a real time data bridge to collect data from one PICS and feed it into another, optionally translating the point IDs in the process; and a "pipe" program that connects to an RTServer, subscribes to all available points, then redistributes them as if it were RTDBA on the local LAN (allowing things like a test lab to utilize live data).

From the point of view of a generic PICS application, there is no difference between RTDBA, and RTClient -- both offer the exact same interface to the real time data stream. In an attempt to reduce confusion, EVI uses the term AGENT (Real Time Agent, in this case) to describe a 'generic' PICS service. Elsewhere in the documentation you will find applications that require a Real Time Agent, which means that they will work with any of the real time database programs offering the data subscription service.

The drawing below attempts to show all of the various flavors of real time family members that exist (anywhere, but not necessarily as part of USEC/PGDP's package). The drawing is complex looking at first, but once you begin to understand how the products relate to each other, sense will begin to emerge... <smile>