With the wide range of devices that use Modbus for their communication protocol, you'll find many different interpretations, terminology and labels with respect to how to access different types of data in those devices. Sometimes a device manual might only refer to the supported Modbus function codes and the range of offsets available for those function codes.
In this blog post, I will step through the specifics of Modbus function codes and how they pertain to addressing, and how they affect what addresses to use in TOP Server for Wonderware applications.