Retrieval

When retrieving data from Historian, you specify either a raw or non-raw sampling mode. Non-raw retrieval can include a calculation mode so that calculations are performed in the archiver before data is returned. This is detailed in the following sections:

• Sampling Modes
• Hybrid Modes
• Filtered Data Queries

Some sampling and calculation modes are better suited to retrieving compressed data. Understanding the available modes helps you choose the best method for your archiving process.