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Use

Manufacturing Data Access is an internal interface that enables data exchange between different applications of the SAP system. Applications that have registered as services at this interface can read and write values of data points from other applications. You can subscribe to events that have occurred in other applications.

Prerequisites

OPC Items and OPC Events

To use data points (items) of the services ODA (OPC Data Access) and OAE (OPC Alarms/Events), you must first have created a subscription in Customizing.

To do so, go to Customizing for Process Management and choose SAP ODA (OPC Data Access) .

For more information about SAP ODA, see SAP OPC Data Access .

Features

The various applications that are linked to each other through the interface are called Services . A service can be used as a client, a server, or both as a client and a server. Clients can request data from other services, while servers provide data for other services. Services that can be used both as clients and servers can provide and request data.

Furthermore, Manufacturing Data Access provides additional functions that you can use to dynamically request data points or events available as well as navigate to their maintenance environment.

Depending on whether the registered application serves as a client or a server, it can use the following functions through Manufacturing Data Access :

A client can:

  • Read data points from another application

  • Write data points to another application

  • Subscribe to events from other applications

    When an application subscribes to events from another application, these events are automatically reported to this application when they occur. In this way, you can, for example, subscribe to value changes.

    In addition, events can contain parameters that you can read while processing an event.

A server provides:

  • Data points that can be read or written by other applications

  • Events to which other applications can subscribe

    Once events occur, they are published by the server.

In this way, you can:

  • Synchronously read or write value of one or more data points,

    this means on request (for example, by pressing a button)

  • Read or write values of one or more data points on an event-driven basis,

    this means that in running applications, data is automatically read or written – triggered by an event – without any user interaction.

Events can also be processed across different sessions.

Example Example

User A maintains PI sheet 001. User B maintains PI sheet 002. Value changes in PI sheet 002 can be transferred automatically to PI sheet 001 although the two users are logged on at different terminals.

End of the example.
Services

The following services and their functions are available in the Production Planning – Process Industries (PP-PI) environment at the moment:

  • MDA: Generic services

  • MSG : Create process messages automatically

  • PSH : PI sheets

  • PMC : Manufacturing cockpits

  • ODA: OPC Data Access

  • OAE: OPC Alarms/Events

  • SYS: System information

Service MDA

The service MDA is used as a server and contains the generic services BROADCAST and REDIRECT.

  • You can use BROADCAST to define user-specific events. A generic data point is available for this to which you can write any value. The value change of this data point is published as an event. Other services can subscribe to this event.

    Parameters of the event can be transferred as data points together with the event.

    For more information, see Manufacturing Events .

    Using REDIRECT, you can address any number of data points dynamically and read or write the values belonging to them.

    When reading tank fill levels in the PI sheet, the process operator can, for example, choose between different tanks. The tank selected is written to a data point as the address. This data point can, for example, be sent by pressing a button or automatically. Somewhere else, the data point can be read along with its value.

    For more information, see Manufacturing Data Points .

Service MSG

The transaction CO60 – Create Process Messages Automatically is a service that serves as a client. In this transaction, you can access manufacturing events and manufacturing data points using Manufacturing Data Access . You can use value help to display all events and data points available across plants:

  • You can specify events as start conditions. The application thus subscribes to the event. Once it occurs, the process message is created automatically.

  • You can read values from different data points and send them with the process message.

For more information, see Creating Process Messages Automatically .

Services PSH and PMC

PI sheets and cockpits are services that serve both as clients and as servers.

The following client functions are possible:

  • Reading data from another application

  • Writing data to another application

  • Subscribing to an event

    You can use events to subscribe to value changes.

The PI sheet and cockpit offer the following server functions:

  • Events to which another application, another PI sheet, or another cockpit can subscribe.

    Example: User Locked On or Document Saved

    For more information, see Manufacturing Events .

  • Global variables that other applications can access as data points

    For more information, see Manufacturing Data Points .

Services ODA and OAE

SAP ODA is a service that is used as a server. This means, it provides:

  • OPC items that can be read by other services (service ODA)

    For more information, see Manufacturing Events .

  • Value changes of OPC items to which other services can subscribe (service ODA)

    For more information, see Manufacturing Data Points .

  • OPC events to which other services can subscribe (service OAE)

    For more information, see Manufacturing Data Points .

Service SYS

This service is used as a server and provides data points containing system information, such as Current date or User logged on . The data access to this service is defined differently by the different client applications.

For more information, see Manufacturing Data Points .

Defining the Data Access

The data access to this service must be defined differently by the different client applications.

  • In the transaction Create Process Messages Automatically :

    You can use value help to select an event or data point. You specify value assignment type Data point for the message characteristics.

    For more information, see Creating Process Messages Automatically .

  • In the PI sheet and in the cockpit :

    You use the following characteristics:

    Characteristic

    Characteristic Value

    PPPI_DATA_ACCESS

    Manufacturing Data Access

    PPPI_IMPORT_DATA

    Data point or global variable of the application from which the value is to be transferred to the subsequent variable

    PPPI_EXPORT_DATA

    Data point or global variable of the application into which the value of the subsequent variable is to be transferred

    PPPI_EVENT

    Internal or external event

For more information on how to define the data access from PI sheets and manufacturing cockpits, see Type 0: Definition of Manufacturing Data Access .

Addresses for Events and Data Points

Addresses are used to access data points and events for data exchange between applications. They start with the name of the service. The remaining address parts depend on the service.

Examples for Event Addresses:

  • ODA:0001.MYITEM.VCHD

    Service ODA , Plant 0001, OPC Item MYITEM, Value has changed

  • OAE:0001.MYSUBSCRIPTION

    Service OAE, Plant 0001, OPC Alarms/Events subscription MYSUBSKRIPTION was triggered

  • PMC:0001.MYCOCKPIT.VARCHGD

    Service PMC, Plant 0001, Cockpit MYCOCKPIT, Value changes at global variables occurred

  • PSH:100000000000004711.LOGIN

    Service PSH, User has logged on to maintain PI sheet 100000000000004711 .

  • MDA:BROADCAST.DEMO

    Service MDA, User-defined event DEMO was triggered

For more information, see Manufacturing Data Points .

Examples for Data Point Addresses:

  • ODA:0001.MYITEM.PV

    Service ODA , Plant 0001, OPC Item MYITEM, Current value

  • PMC: 0001.MYCOCKPIT.MYVAR

    Service PMC, Plant 0001, Cockpit MYCOCKPIT, Value of variable MYVAR

  • PSH:100000000000004711.MYVAR

    Service PSH, Value of variable MYVAR in PI sheet 100000000000004711

  • SYS:TIME.UTC

    Service SYS, current time (Universal Coordinated Time)

For more information, see Manufacturing Events .

Register New Applications as Services

You can use the Business Add-In (BAdI) SCM_CMX_DA_SRV to register any application of the SAP system as a service.

To do so, go to Customizing for Process Management and choose   Business Add-Ins in Process Management   BAdI: Registration of a Manufacturing Data Access Service.   .