Rockwell-automation FactoryTalk Historian SE ProcessBook 3.2 User Guid Manual de usuario descargar pdf (Pagina 275)

7 ● Data Streams

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defined in the order in which they are encountered in the SQL

statement.

13. Click Placeholders to check the syntax of the query. If the syntax is

not valid, the invalid query message is displayed.

14. Click OK.

Custom Data Sets

A custom data set is one provided through a VBA add-in to FactoryTalk

Historian ProcessBook. It is a COM object or a .NET object with a COM

wrapper that acts as an interface between FactoryTalk Historian

ProcessBook and the custom data provider. The source of data could be a

data store (like MS SQL Server) or a data calculation engine. FactoryTalk

Historian ProcessBook requests updates to the data every few seconds and

adjusts its display accordingly.

Before you can access custom data sets in a display, the Data Set add-in

must be installed and loaded through the Add-In Manager (page 13)

dialog box. Later, as you build a display, you select the data set and

column to be used for a symbol on a display through the symbol definition

dialog box boxes. Once a custom dataset is loaded, it is available

throughout the application. These data sets are not display or ProcessBook

specific.

Information on building a custom data set is beyond the scope of this

online help. It is discussed in Creating a Custom Data Set, a white paper

supplied with the FactoryTalk Historian ProcessBook software CD.

Placeholders

A Placeholder in an SQL query identifies a value that is to be provided

when the query is run. You can validate a query before the actual values

are provided.

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Rockwell-automation FactoryTalk Historian SE ProcessBook 3.2 User Guid Manual de usuario Pagina 275