VOLTTRON Historians

Introduction

Historian Agents are the way by which device, actuator, datalogger, and analysis are captured and stored in some sort of data store. Historian Agents for sMAP, general support for SQL based database (sqlite and MySql), and an OpenEIS stores already exist.

• sMAP Historian
• SQL Historian
• OpenEIS Historian

Other implementations of historians can be created by following the developing historian agents section of the wiki.

Historians are all built upon the BaseHistorian which provides general functionality the specific implementations build upon.

By default the base historian will listen to 4 separate root topics (datalogger/, record/, actuators/, and device/. Each of root topics has a specific message syntax that it is expecting for incoming data. Messages that are published to actuator are assumed to be part of the actuation process. Messages published to datalogger will be assumed to be timepoint data that is composed of units and specific types with the assumption that they have the ability to be graphed easily. Messages published to devices are data that comes directly from drivers. Finally Messages that are published to record will be handled as string data and can be customized to the user specific situation. Please consult the Historian Topic Syntax page for a specific syntax.

This base historian will cache all received messages to a local database before publishing it to the historian. This allows recovery for unexpected happenings before the successful writing of data to the historian.