Item Subscription (SAP Library - SAP OPC Data Access (SAP ODA))

Item Subscription

Use

Using this function, the SAP R/3 System can subscribe to certain items of a DA server. Once the value at the item changes, the SAP R/3 System is automatically informed about the current value. The quality and time stamp are read along with the value.

See also: Reading and Writing of Items

Integration

Using SAP ODA, you can access OPC data from the following applications:

In PI sheets

In manufacturing cockpits

In the transaction Create Process Messages Automatically – CO69

For more information about how the data is accessed from the above applications, see:

Type 0: Manufacturing Data Access Definition

Manufacturing Data Access

Manufacturing Data Points

Manufacturing Events

Prerequisites

You have installed the SAP ODA Connector on the target host.
For more information, see Installation and Deinstallation of the SAP ODA Connector.

You have made the settings for SAP ODA in Customizing for the SAP R/3 System.
To do so, you go to Customizing for Production Planning – Process Industries and execute the activities listed under SAP ODA.

Features

When subscribing to Data Access items, you can make the following settings:

An update rate for every DA server

The SAP R/3 System waits according to the specified period before it checks whether a current OPC value exists. If the new value has changed by the absolute deadband, it is reported to the SAP R/3 System.

A percentage deadband for every Data Access subscription

The value of the OPC item is only reported to the SAP R/3 System when it has changed at least by the percentage deadband.
See also: OPC Data Access Servers