Function Tags
The function tag type is used to perform mathematical and logical calculations using numeric values and/or the values of other tags. A function tag can accept up to four tag values or numeric values as properties, and the result of the calculation becomes the value of the function tag. Other tags can use the value of a function tag.
A function tag will return a value of 1 when the specified input tags are Invalid and the AND operation is used. Similarly, a function tag will return a value of 0 when the specified input tags are Invalid.
Function tags are an older technology. They have been superseded by Calculation tags for most applications.
Note: The alarm tag type can also be used for limited function processing (see Alarm Priority Tags).
The characteristics of the function tag type are described in the table below.
Function Tag Type Characteristics
Tag Browser Name: Function
Database Table Name: Function
Type: Miscellaneous
Tag Group Memberships: Numeric, Trenders
Log Enabled Variables: Value
Native Drawing Methods: Function Tag Drawing Methods
Function Tag Type Properties: ID Tab
Function Tag Type Properties: Operator
Tab
Function Tag Type Properties: Inputs
Tab
Function Tag Type Properties: Manual
Tab
Function Tag Type Properties: Owner
Tab
Function Tag Type Properties: Alarm
Tab
Function Tag Type Properties: Script
Tab
Function Tag Type Properties: Logger
Tab
Using Function Tags to Create
Multiple Data Logs of an I/O Tag