Data Flow: EWM Transmits Data 

Purpose

The data flow via the interface between the non-SAP system and Extended Warehouse Management (EWM-WCU interface) is explained using an example communication process flow for transmitting warehouse task data from EWM to the non-SAP system. For more information about the business background, see Scenarios for Connecting Non-SAP Systems.

Prerequisites

You have made the required TCP/IP settings. For more information, see BC – SAP Communication: Configuration.

In Customizing, you have defined the ALE interface. In Customizing, you have specified the circumstances in which a warehouse task (WT) is relevant for transmission to the non-SAP system. For more information, see the Implementation Guide (IMG) for Extended Warehouse Management under Interfaces ® Non-SAP Systems ® Connect Subsystem.

●     For each warehouse number, you can specify that WT items for the following criteria are relevant for transmission to the non-SAP system:

○     For a storage type

○     For a warehouse process type or

○     For combination of storage type and warehouse process type

●     You define the external system, which receives the WT item.

Process

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       1.      When you create a warehouse task (WT) in EWM, the Customizing settings define that the WT or WT item is relevant for transmission to the non-SAP system.

       2.      During creation of the WT, the system prepares the data to be transmitted, in the form of an IDoc.

For more information about IDocs and their construction, see Description of the IDocs.

       3.      The system saves the created IDoc to the database.

       4.      Asynchronously to creation of the IDoc, the system uses ALE to trigger transmission of this IDoc to the non-SAP system.

The system can transfer individual IDocs or collect several IDocs and then transfer them to the external system later. The transmission is based on Remote Function Call.

       5.      The non-SAP system must be ready to receive the transmitted data with a relevant program.

For more information, see Basis ® Basis Services/Communication Interface ® Remote Communications ® The RFC API ® Programming with the RFC API.

       6.      The non-SAP system saves the received IDoc data, and sends a receipt confirmation to the SAP system.

We recommend that you save the transmitted data in the non-SAP system first, to ensure that transmission of the IDoc and processing of the transmitted data occur separately.

       7.      Status management for the data received should prevent the external system from processing the data twice.

The external system should be able to recognize IDocs that have been transferred by the SAP system before. This is made possible by the unique transaction identification number (transaction ID), which the SAP system assigns for each communication process. For more information, see Basis ® Basis Services/Communication Interface ® Remote Communications ® The RFC API ® Transactional RFC Client Programs.

The external system can also recognize double transfers from the IDoc number external system can also use the IDoc number to identify duplicate transfers. Note that an IDoc number is only unique within a single client in an SAP system. If several clients of an SAP system or several SAP systems are involved in the communication with the external system, the IDoc number is no longer unique. In this case the external system cannot recognize IDocs that have been transferred twice from this number.

Error Processing

If you receive an IDoc from EWM to a non-SAP system, the following problems can occur:

Troubleshooting

Symptom	What You Should Know
Update termination in the SAP system during the application	An update termination during creation of a warehouse task does not affect communication with the external system, because the system only creates an IDoc once the source SAP system document exists. The WT and the IDoc are creates in the same LUW, therefore they are updated synchronously.
Error in the ALE interface: Transferred data is syntactically incorrect	ALE adopts the IDoc and saves it, but cannot transfer the IDoc to the external system. For more information, see IDoc Error Processing.
Error in the ALE interface: ●     The outbound partner profile for the receiving system ●     The IDoc message type are not defined	For more information, see IDoc Error Processing.
There is no connection between the SAP system and the external system	The SAP system tries to set up the connection to the external system by running a report in the background at a later time. As soon as the connection between the two systems exists again, the SAP system automatically transfers all IDocs, which have not yet been sent. You can also start this report manually. For more information, see Processing Technical IDoc Errors.