Differentiating the SAP Solutions for Warehouse Management

Objectives

After completing this lesson, you will be able to:
  • Describe warehouse management systems.
  • Process a goods receipt in SAP ERP warehouse management.
  • Process a goods receipt in SAP ERP decentralized warehousemanagement.
  • Execute an inbound process in SAP EWM.

Warehouse Management

Depending on the number, variety, and diversity of the products you purchase, sell, or produce, you may have different requirements for storing these materials, as the following examples indicate:

  • A mining company that digs ore and sends it directly to a refining factory does not need to store the ore.  That company does not need a warehouse.
  • A factory that refines ore to produce steel needs a simple warehouse to hold the steel until it is sold to a customer.
  • A distributor receiving thousands of products from many manufacturers and distributing those products to hundreds of customers needs a complex warehouse. That warehouse needs to facilitate the following tasks, among others:
    • Track the product received
    • Determine the storage bins to store the incoming product
    • Track current stock levels for each product
    • Determine the storage bins to pick the product from (before distributing that product)
    • Track the distributed product

Why Use a Warehouse Management System?

Inventory must be stored efficiently to satisfy customer orders and supply production with raw materials.

Warehouse Management means the management of stock and the management of the locations where that stock is stored. When running a business, it is essential to fulfill customer orders without delay. Although it may be difficult to forecast customer-order requirements, you try to have stock for order fulfillment.

Manufacturing plants often use a Just-In-Time model, which means that they hold very little stock in their warehouse. The advantage of this is reduced warehousing costs. The disadvantage is that there may not be enough stock to meet production requirements to fulfill customers’ orders. It is very important for a successful business to hold sufficient stock and to avoid that situation.

Three warehouses in separate panels, the first of which is loading a boat, the second is on a dock, and the third features trucks and cargo bays.

Warehouse Management System Functions

A Warehouse Management system (WMS):

  • Tracks the amount of a particular good or material that is stored in a warehouse.
  • Tracks the storage bins that holds a particular good or material.
  • Controls and records all movements of goods and materials in the warehouse.

Also, a Warehouse Management system can increase warehouse efficiency. It can provide tools to monitor warehouse activities and to plan resource requirements, for example, warehouse staff or equipment resources, and so on.

Large warehouses with many storage bins and many different goods and materials need a Warehouse Management system to be efficient and satisfy customers' needs. They use a Warehouse Management system to:

  • Control the putaway of goods and materials that come into the warehouse. The Warehouse Management system determines an available and suitable storage bin to store the goods or materials.  
  • Control the picking of goods and materials to leave the warehouse, for example to fulfill an order. The Warehouse Management system determines a stocked and suitable storage bin to pick the material from.

Complex Warehouses

In more complex warehouses, additional functionality can be provided to manage other information or services related to goods and materials, for example:

  • Serial number
  • Batch number
  • Minimum shelf life
  • Vendor managed inventory (VMI)
  • Yard Management
  • Value-added services (VAS)

Examples of warehouses with this level of complexity include distribution centers or logistics service providers. Warehouses become more complex as they become responsible for value-added services (VAS) tasks, for example, packaging.

When knowing the quantity of your stock (without knowing the location of that stock and other information) is insufficient, then you know that you need a Warehouse Management system.

SAP Warehouse Management Solutions

Business Solutions

With the availability of SAP Extended Warehouse Management (EWM) as strategic WM application, it is important to decide which warehouse management application is best for your business. Which of the available SAP solutions is the right one for your needs?

SAP Warehouse Management (WM), part of SAP R/3 (version 2.0), was released in 1993, and SAP has continuously improved SAP WM from release to release. The introduction of SAP EWM in 2005 did not directly replace the SAP WM system. Instead, it provided an alternative for warehouses that required the functionality available in SAP EWM.

However, the customer must be aware that the end of mainstream maintenance for SAP Business Suite 7 core releases also means that for SAP WM as part of SAP ERP 6.0, maintenance ends in 2027 (see note 1648480 – Maintenance for SAP Business Suite 7 Software).

SAP S/4HANA, the next generation ERP solution from SAP, includes SAP WM and since SAP S/4HANA 1610, it also includes embedded EWM. SAP WM is part of a compatibility pack and can be used in its current version until the end of 2025. For details see the SAP Note 2269324 - Compatibility Scope Matrix for SAP S/4HANA on-premise. It is then directly replaced by Stock Room Management in SAP S/4HANA. For details see SAP Note 2270211 - S4TWL - Warehouse Management (WM) and 2881166 - FAQ : Stock Room Management.

Warehouse management can mature from no management to lean, basic, decentral, and extended solutions, all built on the same foundational system for scalability.

SAP Warehouse Management

Main Functions in Warehouse Management/Stock Room Management

The main functions in Warehouse Management / Stock Room Management are:

  • Managing inventory at the storage bin level
  • Mapping and control of all goods movements with transfer orders
  • Monitoring the processing of all goods movements
  • Connecting to mobile data entry as part of an integrated radio frequency solution
This diagram illustrates the integration of Inventory Management, Shipping, and Warehouse Management in ERP systems, highlighting goods movement and storage processes.

Note

The ERP system in the preceding picture could be a SAP Business Suite ERP, as well as an SAP S/4HANA system.

Warehouse Management (LE-WM) will be replaced by Stock Room Management in SAP S/4HANA. Stock Room Management reuses major parts of LE-WM and can be used beyond 2025. Task and Resource Management (WM-TRM), Warehouse Control Unit interface (WM-LSR), Value Added Service (WM-VAS), Yard Management (WM-YM), Cross-Docking (WM-CD), Wave Management (WM-TFM-CP), and decentral WM (WM-DWM) are not part of Stock Room Management.

Lean WM is a simplified version of WM. Both are based on the same principles, but Lean WM does not manage the inventory at the storage bin level. Lean WM is a good solution for a customer which has only a limited number of materials and uses only a fixed bin strategy.

ERP Decentralized Warehouse Management

Especially in warehouses with a high throughput, the Warehouse Management system must always ensure quick response times. If the Warehouse Management system runs on the same machine as the ERP system, performance problems may arise.

Also, at some warehouses, the WMS must be available 24 hours a day. This is regardless of whether other systems are available or not.

24-hour availability must be combined with a low risk of downtime. This is to ensure that the WMS can perform all logistics processes, which are often closely integrated.

For these reasons, you can install an SAP system as an independent, decentralized Warehouse Management system to receive requests for goods movements from any Enterprise Resource Planning system.

The image illustrates the integration between ERP inventory management and warehouse management, highlighting inbound/outbound deliveries and goods movement via transfer orders.

Note

Both ERP systems in the preceding picture could be SAP Business Suite ERP or an SAP S/4HANA systems. In the case of SAP S/4HANA systems, only as long as the usage of ERP Warehouse Management is still allowed.

Technically the system for Inventory Management / Shipping can also be an SAP S/4HANA system, which is connected to an ECC system as warehouse management solution.

Decentralized WM

In a decentralized WM, the WM is logically or physically separated from the ERP System, therefore:

  • The ERP system manages processes, for example the creation of sales orders, purchases orders, and the corresponding deliveries.
  • The decentralized WM manages warehouse processes - for example, goods receipt, storage, goods issue, and monitoring warehouse activities.

Although the WM is separate from the ERP System, communication is essential. This is achieved as follows:

  • Inbound and outbound deliveries (in the ERP system) are replicated using Business Application Programming Interfaces (BAPIs) to the decentralized WM system. 
  • Goods movement, when finalized or "posted" in the decentralized WM, are replicated using BAPIs to the ERP System.

Warehouse Management Functions and Processes in SAP EWM

In 2005, SAP released its Service Parts Management (SPM) solution.  SAP Extended Warehouse Management (EWM) was an integral component of this solution.

Today, SAP EWM is considered a standalone application that can be used in any warehousing environment. It does not require any connection to SPM. Since the introduction of SAP EWM, SAP has continuously enhanced the product.

From an ERP point of view, SAP EWM is a decentralized WM solution. This means that inbound and outbound deliveries are mandatory.

The SAP EWM primary functions are:

  • Inventory management at storage bin level
  • Storage bin determination for incoming goods
  • Stock removal for outgoing goods
  • Stock transfers
  • Physical inventory management
The graphic illustrates the integration between ERP and EWM, showing the flow from inventory management and shipping to extended warehouse tasks, storage, and deliveries.

Note

The ERP system in the preceding picture could be a SAP Business Suite ERP, as well as an SAP S/4HANA system.

The embedded EWM in SAP S/4HANA is technically also a decentralized solution. So, even if there are no separate systems as in a decentralized setting, the inbound or outbound delivery is "distributed" from one part of the system to the other. But certain processes meanwhile allow you to work without deliveries, depending on the SAP S/4HANA release.

Additional Functions for Warehouse Management

Warehouse operations flow: inbound processing, storage/operations, and outbound processing, highlighting analytics, labor management, value-added services, and tools.

Along with the primary functions, various additional functions are provided to improve warehouse management:

  • Slotting
  • Consolidation and deconsolidation
  • Cross-docking
  • Yard management 
  • Complex internal routing
  • Value-added services (VAS)
  • Labor management
  • Radio frequency identification
  • Kit-to-stock / Kit-to-order

The warehouse management monitor is another powerful tool. This tool allows you to do the following tasks:

  • Supervise and deal with your warehousing documents and processes
  • Check your stock and storage bins
  • Monitor your employees and resources
  • Check the warehouse workload
  • Supervise the material flow system (MFS)

SAP EWM is designed for the management of complex supply chain networks. It can be used for warehouses or distribution centers with:

  • High throughput of various goods with differences such as:
    • Size
    • Weight
    • Serial number
    • Country of origin
    • Batch
    • Valuation
  • Complex cross-docking and order-fulfillment requirements
  • Detailed packaging and shipping logistics requirements

EWM System Environment and Deployment Options

The Extended Warehouse Management system, as an application in the SAP SCM solution, is designed as a decentralized warehouse management system. Originally, it was built on the SAP SCM platform and could be deployed together with Advanced Planning and Optimization (APO) or Global Available-To-Promise (Global ATP) on one system. SAP EWM 9.5 was the last version based on the SCM platform. The successor release is based on an SAP S/4HANA system and can be used as an embedded or a decentral version.

Comparison of SAP S/4HANA Cloud and on-premise deployment options for Extended Warehouse Management, highlighting decentralized vs. embedded approaches and benefits.

Which ERP system can be connected depends on the SAP EWM version. When using a SAP Business Suite based decentral EWM (which is not pictured), the EWM system can be connected to SAP systems from R/3 4.6C and higher (including SAP R/3 Enterprise and all subsequent SAP ERP releases) or any SAP S/4HANA system. A decentral EWM based on SAP S/4HANA requires a SAP ERP 6.0 EhP 3 or higher, or SAP S/4HANA OP1611 or higher. Depending on the release of the ERP system or any Enhancement Packages installed, certain functions or processes in SAP EWM might be unavailable. Details are described in the release notes, installation guides, and notes.

Since SAP S/4HANA 1610 EWM is technically included as embedded EWM, this means that no separate installation is necessary. That approach has certain advantages, but also restrictions that must be considered.

The options of a decentral or embedded deployment are also available in SAP S/4HANA Cloud, private edition. There the decentral option is called extra-stack, the embedded option is called in-stack.

Warehouse Management in SAP S/4HANA Cloud, public edition, is based on EWM, with a smaller scope in functionality

Note

Warehouse Management in SAP S/4HANA Cloud, public edition, is not part of this course.

Note

For a high-level overview about the capabilities of the different offerings, please use the presentation in the following link: https://d.dam.sap.com/a/kX5ogZc/EWM_PCE_vs%20Standalone%20CE_V1_022023%20(3).pdf?rc=10

For details of the different deployment options, and the aspects to be considered, please see the SAP note "1606493 – SAP EWM deployment options best practices". The major differences between embedded EWM in SAP S/4HANA 2020 and a de-central EWM are described in SAP note "3376453 - SAP S/4HANA 2023 FPS00: Release information and restrictions for EWM in SAP S/4HANA" and "3376455 - Release information and restrictions of Decentralized EWM on S/4HANA 2023 FPS00". Please check for further notes related to subsequent or previous releases.

SAP Warehouse Management Options (S/4HANA Cloud, private edition and S/4HANA on premise)

It is possible to use different warehouse management solutions in parallel in your ERP system. There are three organizational units which together controls how the stock is managed.

The plant is an operational facility within a company (e.g. a production facility, regional or branch office) and the highest organization unit in logistics. The plant subdivides an enterprise from the viewpoints of production, procurement, maintenance, and materials planning.

The storage location is an organizational unit allowing the differentiation of material stocks within a plant. Material always belongs to a combination of plant and storage location.

Note

This means that a storage location is not a physical structure (as the following picture or the name implies). It is a logical separation of stocks, but not necessarily a physical separation.

A physical warehouse is defined under a single warehouse number. Using the warehouse number, you can manage several individual warehouse buildings that, together, form a complete warehouse complex.

Through the assignment of a combination of plant and storage location to a warehouse number and the settings for this warehouse number, you define the type of warehouse management you use.

Supply chain flow showing a manufacturing plant, a warehouse for finished goods, and a storage location for bulk materials or products, highlighting logistics stages.

SAP S/4HANA Warehouse Management Options

The basic definitions for logistic organizational structures (plant, storage location, warehouse number) in SAP S/4HANA are the same as in SAP Business Suite ERP. Through the inclusion of embedded EWM in SAP S/4HANA, there are additional options for the warehouse management solution.

Comparison of various SAP S/4HANA warehouse management solutions and their integration with different storage locations within Plant 0001, including IM, WM, EWM, and non-SAP WMS.
  • #1: Of course it is not required to use a warehouse management system, so you can continue to use only inventory management for a combination of plant and storage location. That means you have no warehouse number.
  • #2: Lean WM is possible as option in a warehouse number.
  • #3: As part of the compatibility packs it is possible to use WM in SAP S/4HANA until the end of 2025.
  • #4: Stock Room Management reuses major parts of LE-WM and can be used beyond 2025. For details about this solution see the SAP Note 2270211 - S4TWL - Warehouse Management (WM).
  • #5: This option would mean that you use a decentral WM, based on SAP Business Suite. The planned availability for this option is until the end of 2027, when the SAP Business Suite solution mainstream maintenance will end.
  • #6, 7, and 8: The warehouse number is set up as decentral warehouse, either with an EWM based on SCM or on SAP S/4HANA, or with a non-SAP warehouse management solution. What needs to be considered is the mainstream maintenance for the SCM based EWM, which is planned to end 31.12.2025 (for SAP EWM9.5).
  • #9 and 10: In SAP S/4HANA, you can use embedded EWM either as Basic Warehouse Management or Advanced Warehouse Management. The details are described in the Feature Scope Description of your SAP S/4HANA Release.

Note

The preceding slide always show a combination of one plant and storage location with one warehouse number. But a warehouse number can be connected to several plant and storage location combinations, with the same plant or also with other plants.