Process data: About tags and values

AVEVA Historian acquires and stores process data, which is any information related to successfully running a process. That data is stored as tags.

The term "tag" originally referred to physical label on a mechanical part or device on the plant floor. Each tag identifies the corresponding device to AVEVA Historian. As each device sends values to the historian, they are recorded by tag.

For example, a boiler might have two tags – one for the temperature gauge and one for the volume meter.

Using process data to answer your business questions

Historian stores and retrieves your process data in a way that allows you bring clarity to issues related to your business.

• Real-time data
  Historian stores data as it comes in from the plant floor.

  Real-time data answers questions like "What's the temperature of that tank right now?"

• Historical data
  Historian can accept historical information from other systems and retains data captured in real time to use for historical reference.

  Historical data helps to answer questions like "What was the value of this tag every second last Monday?"

• Summary data
  Historian summarizes certain data to help answer with big-picture questions like "What is the average number of bags produced each week?"

• Event data
  Historian records process alarms and events as they happen. This data is used to find answers about when things happened; for example, "How often did that boiler trip last month?"

• Configuration data
  This data describes your system’s configuration and answers questions like "What types of I/O Servers am I using?"

Process data analysis can help improve performance, enhance quality, and reduce costs.

For more information about defining and using tags, see Defining Tags in the AVEVA Historian Administration Guide.