Understanding SAP Decentralized Warehouse Management

There is a key word called “WMS”. Every Warehouse consultant should come across WMS Legacy system that takes care the warehouse operations and need to replace with SAP WMS as part of SAP implementation.  SAP designed a Warehouse system that delivers high level efficiency in the supply chain activities. This blog post will covers important concepts of SAP Decentralized Warehouse management. In theory SAP (DWM)S is describes as a decentralized stand-alone system that is operated separately from a centralized operated ERP system (ECC).



First of all Warehouse Management System has been implemented for the “distribution center “ scenario. This scenario describes a warehouse that primarily used to distribution of goods and is not linked to production plant. All business processes are carried out in ERP system where as decentralized WMS is responsible for the necessary process for goods reciept, warehousing and distribution.

SAP ECC to DWM concept

A Decentralized Warehouse Management (DWM) system is designed to only run warehouse operations : Goods receiving, Stock placement, Stock removal (Picking), Packing and Cycle counting. DWM runs on a different SAP server to the main SAP ECC server. Not all of the enterprise structure is required in DWM.
–Customers & Vendors only require addresses.
–Material masters only require a subset of data.
–These masters will look different to the ones in ECC, as certain data is missing in DWM.
–The material master has had certain views removed in DWM.
–No inventory management available in DWM. Eg. Transaction MMBE doesn’t work.

Master data replication: Customer master,Vendor master,Material master, Batch master, and Classification Master
Inbound: Processing in ECC using inbound deliveries, Replication of inbound delivery from ECC to DWM, Inbound staging lane processing, Goods receiving posting, Stock placement
Outbound: Delivery creation, Wave Planning (WP),Picking & packing and Post goods issuing.

Data Replication: SAP Standard Application Link Enabling (ALE) is used to replicate master data from ECC to DWM (IDoc’s). Only a subset of data is moved to DWM, as the full masters are not needed. Custom message types have been created for material, customer and vendor masters in order to reduce the amount of data replicated to DWM.



–MATMAS for material master
–DEBMAS for customer master
–CREMAS for vendor master
-BATMAS for batch master and
-CLFMAS for classification master

Change pointers are used to identify changes to master records for replication to DWM. Replication runs on a periodic basis (Every 15 minutes). To see which fields create change pointers run transaction BD52 for the message type. The change pointer table and the IDoc message need to be in sync. The IDoc’s messages are setup in BD53.

These changes are then processed in ECC using ABAP program RBDMIDOC using the relevant message types. This program creates the IDoc’s and sends them to the relevant DWM systems where they will reside in status 64. In every DWM systems, ABAP program RBDAPP01 is run using the relevant message types to process the IDoc. There are batch jobs in each of the systems that run every 15 minutes to process the data. If  for some reason the change pointers don’t work, or there is a need to send data ad hoc, then the following transactions can be used.

Material Master – BD10 with message type MATMAS
Customer Master – BD12 with message type DEBMAS
Vendor Master – BD14 with message type CREMAS

Inbound: Inbound deliveries are created with reference to purchase orders. The confirmation key in the purchase order is set to allow inbound delivery creation with goods movement (“Inbound Delivery”) Purchasing info record holds the confirmation key. After an inbound delivery is created, it’s automatically replicated to DWM. Incompletion log is set not to replicate if batches are missing from inbound delivery. Inbound deliveries are created via an Interface or created manually. When SAP Stock Transport Orders are used, the inbound delivery is created from the outbound delivery via standard SAP output type, copying all HU data. Change management is turned on for inbound deliveries. Transfer orders are created with reference to the inbound delivery. When the transfer orders are confirmed the goods receipt is posted in DWM, and automatically replicated to ECC.



Goods Receiving IDoc’s: IDoc’s that are used in ECC & DWM:-
–Outbound ( In ECC )

•BAPI Function Module for Replication of Inbound Deliveries
–SHP_IBDLV_SAVE_REPLICA04
•Change inbound delivery
–SHP_IBDLV_CHANGE01
Inbound ( In ECC )
•BAPI Confirmation (Inbound Delivery)
–SHP_IBDLV_CONFIRM_DECENTRAL03
•Change inbound delivery
–SHP_IBDLV_CHANGE01
–Outbound ( In DWM )
•BAPI Confirmation (Inbound Delivery)
–SHP_IBDLV_CONFIRM_DECENTRAL03
•Change inbound delivery
–SHP_IBDLV_CHANGE01
–Inbound ( In DWM )
•BAPI Function Module for Replication of Inbound Deliveries
–SHP_IBDLV_SAVE_REPLICA04
•Change inbound delivery
–SHP_IBDLV_CHANGE01

Outbound: Deliveries are created in ECC, and automatically replicated to DWM. Deliveries are processed in DWM via Wave picking to create transfer orders and perform cartonization. Deliveries are picked and packed in DWM. Transfer orders are confirmed in DWM. Post goods issue is posted in DWM, and is automatically replicated to ECC.



Outbound Shipping IDoc’s:

•IDoc’s that are used in ECC & DWM:-
–Outbound ( In ECC )
•BAPI Function Module for Replication of Outbound Deliveries
–SHP_OBDLV_SAVE_REPLICA05
•BAPI for Change to Outbound Delivery
–SHP_OBDLV_CHANGE01
–Inbound ( In ECC )
•BAPI Verification (Outbound Delivery)
–SHP_OBDLV_CONFIRM_DECENTRAL04
•BAPI for Change to Outbound Delivery
–SHP_OBDLV_CHANGE01
–Outbound ( In DWM )
•BAPI Verification (Outbound Delivery)
–SHP_OBDLV_CONFIRM_DECENTRAL04
•BAPI for Change to Outbound Delivery
–SHP_OBDLV_CHANGE01
•BAPI for Create Shipment
–SHIPMENT_CREATEFROMDATA
–Inbound ( In DWM )
•BAPI Function Module for Replication of Outbound Deliveries
–SHP_OBDLV_SAVE_REPLICA05
•BAPI for Change to Outbound Delivery
–SHP_OBDLV_CHANGE01
Other IDoc’s

IDoc’s that are used in ECC & DWM:-
–Outbound ( In DWM )
•BAPI Function Module posting inventory changes (Cycle counting)
–MBGMCR
–Inbound ( In ECC )
•BAPI Function Module posting inventory changes (Cycle counting)
–MBGMCR

The replication path is generated through the distribution model, which is created under transaction BD64. Attached to the distribution model are the partner profiles, which can be seen in WE20. There is a distribution model for each DWM instance, where filters are used within the model to send only relevant data to the DWM systems.

Links from Help.Sap.com

SAP DWM

Note: Users don’t like one concept of SAP DWM, i.e canceling PGI. There is no option to cancel PGI in DWM facility. The only way is to make a return delivery and revert back.