Archive Datasources

Overview

The archive datasources allow accessing historical data as a PV. There are two types of archive datasources:

  1. archive: Retrieves a single archived value at a particular instant of time.

  2. replay: Creates a PV that recreates changes in values based on data from the archive.

Archive PV Syntax

The prefix for the datasource is archive://, which can be omitted if configured as the default datasource. The archiver PVs are read-only and constant.

  • archive://pv_name: Retrieves the latest value in the archiver.

  • archive://pv_name(time): Retrieves the last value at or before the specified “time”.

Replay PV Syntax

The prefix for this datasource is replay://. The replay PVs are read-only and constant.

  • replay://pv_name: Retrieves the last 5 minutes of data for this PV from the archiver and replays them at 10Hz.

  • replay://pv_name(start, end): Recreates the PV value changes using the data from the archiver between the specific start and end times.

  • replay://pv_name(start, end, update_rate): Recreates the PV value changes using the data from the archiver between the specified start and end times. Updates occur at the rate specified by update_rate (a value defined in seconds).