The data flow across the interface between the Warehouse Management system (WMS) and the external system (WMS-WCU interface) is explained using the example of the communication flow for transferring data relevant to a transfer order (TO) from the external system to the WMS.
For further information on the business background, see
Scenarios for Connecting External Systems.Prerequisites
You have defined the necessary TCP/IP settings. For more information, see
BC - SAP Communication: Configuration.You have defined the ALE interface in the Customizing for Warehouse Management under Interfaces ® External Systems ®
Configure Warehouse Management ® Warehouse Management View ® Activate Interface per Whse Number.Process Flow
The transfer is based on the
The central function module is in the ALE layer. As soon as the external system calls the function module on the SAP system side, the external system can transfer several IDocs.
If an IDoc type is only designed to be transferred individually, this is noted in the relevant IDoc system documentation.
If the system cannot successfully transfer IDocs, you must ensure that these IDocs are transferred again at a later time.
The external system must always provide the transferred data with this transaction ID. If the external system transfers an IDoc for a second time due to unsuccessful communication at an early time, the external system must issue the same transaction ID again.
The SAP system does not use the IDoc number to recognize a double transfer of IDocs from the external system.
On the basis of the processing status, ALE triggers error processing of the IDoc where necessary.
Error Processing
When you receive an IDoc in the WMS from an external system, the following problems may occur:
Troubleshooting
Symptom |
What You Should Know |
There is no connection between the external system and the SAP system |
Using status management, the external system should ensure that IDocs can be transferred again at a later time. |
Error in the ALE interface: There are syntactical errors in the data that the external system sent to the ALE |
ALE adopts the IDoc and saves it, but cannot transfer the IDoc to the WMS for processing. For more information, see IDoc Error Processing. |
Error in the ALE interface:
are not defined |
For more information, see IDoc Error Processing. |
Application errors in the WMS |
If errors occur in the processing of the received IDoc, the WMS transfers the processing status correspondingly. For more information, see Processing Logical IDoc Errors in the WMS. |