Understanding retrieval modes

Different retrieval modes allow you to access the data stored in an AVEVA Historian in different ways. For example, if you retrieve data for a long time period, you might want to retrieve only a few hundred evenly spaced data points to minimize response time. For a shorter time period, you might want to retrieve all values that are stored on the server to get more accurate results.

An AVEVA Historian with a version earlier than 9.0 supports two retrieval modes:

• Cyclic Retrieval

• Delta Retrieval

An AVEVA Historian with a version of 9.0 or higher supports various additional modes:

• Full Retrieval

• Interpolated Retrieval

• "Best fit" retrieval

• Average Retrieval

• Minimum Retrieval

• Maximum Retrieval

• Integral Retrieval

• Slope Retrieval

• Counter Retrieval

• ValueState Retrieval

An AVEVA Historian with a version of 10.0 or higher supports the following additional mode:

• RoundTrip Retrieval

An AVEVA Historian version 11.6.14101 or higher supports the following additional mode:

• Predictive Retrieval

An AVEVA Historian with a version of 17.3.100 or higher supports the following additional mode:

• Bounding value retrieval