HistorianAbout User-Defined Data Types
Sometimes, a single tag cannot store all the required details of a parameter. For example, if you want to store the name, address, and phone number of the manufacturer of a machine, it may not be feasible to store all these details in a single tag, which uses a single data type. In such cases, you can create a user-defined data type (UDT), which includes one or more fields, and then apply that type to Historian tags. Each of these fields in a UDT can contain a different data type based on your requirement.
The following conditions apply when working with a UDT:
- You must have appropriate security permissions to create, modify, and delete a UDT. The type can have its own Administrator security group.
- You cannot create an array tag that uses a UDT.
- UDTs cannot have fields of Scaled or FixedString data types.
- Scaling, collector compression, and archive compression do not apply to UDT tags.
- You cannot associate an enumerated set with a UDT tag.
- A UDT supports maximum 100 fields.