I am not SAP-ean but recently been having discussion around WM so I try to learn more about this. What I wrote here is based on my research over the internet, you can look from the source link from below.
I found these information from our team of experts with SAP EWM Interface, SAP Blog: https://blogs.sap.com/2013/08/04/sap-scm-ewm-vs-sap-ecc-wm/ ,
SAP Documentation: https://help.sap.com/saphelp_scm50/helpdata/en/58/c69040bca2ef4ae10000000a1550b0/frameset.htm , and
First : What is SAP?
SAP – German Company, Enterprise Software (ERP).
Second : What is WMS?
This is broader term, WMS refers to Warehouse Management System, keeping track of the load in the warehouse with detailed attributes – unit by unit. Unlike Inventory System, which only capture the overall quantity.
This post will specifically talk about SAP WMS.
Third : When it started?
SAP WM was introduced since SAP R/2 in the 1970’s (around 1978, 1979).
It is further enhanced during 1990’s (around 1991) when SAP introduced SAP R/3. It is important to know that SAP R/3 is the most popular version, it enables Enterprises to run SAP on Client-Server.
SAP EWM was introduced since 2005.
EWM is the abbreviation of Extended Warehouse Management, the most significant functionality advancements include labor management, slotting and Material Flow Systems.
At the same time, SAP R/3 has evolved into SAP ECC 5.0 (2004) and ECC 6.0 (2006).
Fourth : Compare SAP WMS vs EWM for Automated Warehouse
Material Flow Systems.
SAP EWM is designed to allow the WMS to directly control automation without the use of what is commonly known as a Warehouse Control System or WCS.
Detailed Storage Bin Management, Storage System Control does not exist in the ERP.
If I may sketch the communication between ERP, EWM, and Automation Systems:
Blue Box refers to SAP component. Orange Box refers to Automation Component.
SAP WMS (which is built into SAP ECC, as part of the ERP) do not have the functionality to manage and control automation.
While SAP EWM with slotting and material flow systems will have the capability to speak to the Automation Systems in the warehouse.