Read Functions Overview

You can use read functions to retrieve raw, sampled, and calculated values stored in the Historian server for usage in reporting, plotting, or data analysis applications.

In most cases, multiple tags can be read in a single function call.

Most of the read functions serve the general purpose of retrieving raw, sampled or calculated data. Additionally, targeted functions are exposed to provide easy access to current tag values or values interpolated to a specific date and time stamp.

Comments, if they exist, are returned with retrieved data. See the sample programs for more information.

You can combine read functions with write functions to read back newly written data, which is the most secure way to verify successful data writes.

Read Functions