Understanding Units of Measure in SAP Extended Warehouse Management (EWM)

Introduction

Efficient inventory and transaction management in SAP Extended Warehouse Management (EWM) requires a clear understanding of the Units of Measure (UoM) applicable to different materials. This article explores the key concepts of Base Unit of Measure (Base UoM) and Preferred Unit of Measure (Preferred UoM), explaining their significance and impact on warehouse operations.

Additionally, we will discuss how EWM utilizes quantity classification based on UoM to ensure accurate putaway sequencing and workload planning for inbound operations. The article will also cover the role of Stock-Specific UoM in outbound deliveries, highlighting the differences in UoM management between inbound and outbound processes.

Base Unit of Measure (Base UoM)

The Base UoM in SAP represents the fundamental unit in which a material's inventory is managed. It serves as the default unit for all inventory transactions, including goods receipts, goods issues, and stock transfers. Any other unit of measure used for the material is converted into the Base UoM for transaction purposes.

For example, if a material's Base UoM is "pieces" (EA), all stock movements and counts will be recorded in pieces, even if the material is procured or sold in boxes or cartons.

EWM strictly manages stock and transactions in the Base UoM. Consider the following example:

• A product is manufactured with Base UoM = Each (EA).
• 240 EA are packed into one Carton (CTN).
• 36 CTN are further packed into one Pallet (PAL), resulting in: 1 PAL = 8640 EA

If three pallets are shipped to a distribution center (DC), the inbound delivery (IBD) will be created in the receiving plant as 25,920 EA. This can present challenges for inbound operators:

1. Manual Conversion Complexity: Operators must manually convert the received quantity from EA to PAL when performing physical goods receipt (GR) verification.
2. Workload Planning: Estimating the number of pallets expected on a given day for resource allocation can be difficult when working with Base UoM.

Preferred Unit of Measure (Preferred UoM)

To address these challenges, EWM 9.0 introduced Stock-Specific UoM, allowing warehouses to define a unit of measure as Stock-Specific UoM at the warehouse level. This can be configured as follows:

• Navigate to SAP EWM Customizing and activate the "Stock-Specific UoM" and "Apply AUoM" settings.
• Define UoM attributes under: Extended Warehouse Management > Master Data > Product > Define Unit of Measure Attributes.

Advantages of Preferred UoM

With the Preferred UoM feature, warehouses can determine the UoM in which inbound deliveries (IBD) should be created. For example, if the product is always received and sold in pallets, setting Preferred UoM as PAL ensures that the IBD is created as 3 PAL instead of 8640 EA.

Additionally, the Preferred UoM is transferred to the stock quantity (quant) as Alternative UoM (Alt UoM).

2857703 - PUoM (Preferred UoM) is not displayed in the Warehouse Data tab of transaction code /SCWM/MAT1 - SAP for MeSales Unit of ERP material master can be transferred to EWM Preferred UoM. Refer OSS Note 1637067 - Transferring the Preferred UoM to EWM using CIF

Key Considerations

• If automatic packing is enabled for IBD, handling units (HUs) are created based on the packing specification (packspec). In this case, stock is referenced in Alternative UoM as HU content.
• Operators have the flexibility to manually adjust Stock UoM during the inbound packing process.
• The Preferred UoM is beneficial when purchase orders (POs) and IBDs are created in Base UoM in ERP, but the warehouse prefers transactions in the Preferred UoM (e.g., Case).

Relevant SAP Notes:

• 2988806 – Apply Alternative UoM from ERP delivery in EWM
• 2745415 – AUoM during Warehouse Task creation
• 3275037 – Incorrect UoM and Quantity Classification (QuanCla) for packed stock during putaway

Alternative UoM as Stock-Specific UoM

If Alternative ERP AUoM is configured as Stock-Specific UoM (SUoM) at the EWM item type level, the inbound delivery in ECC (ERP Central Component) will be created in the Alternative UoM (e.g., CV - Cases) instead of the Base UoM (EA - Each). The same UoM is adopted in EWM IBD, ensuring that stock is stored in Alternative UoM (CV) instead of Base UoM (EA).

If the ERP IBD is created in Base UoM, then EWM IBD will also be created in Base UoM. However, if Preferred UoM is set at the product master level, it will take precedence.

Storage Type Considerations

At the storage type level, EWM provides options to:

1. Control whether multiple Alternative UoMs (e.g., Case, Pallet) can be mixed within the same bin.
2. Define how the Alternative UoM attribute should be handled upon putaway into the same bin.

Alternative UoM for Quantity Classification

Before EWM 9.0, EWM determined the Alternative UoM based on the Packaging Specification. A condition record (type 0WHT) had to be maintained, pointing to the relevant packaging specification for the product and supply chain unit.

With the introduction of Stock-Specific UoM (SUoM), warehouses can now:

• Define Quantity Classification based on UoM.
• Ensure that Quantity Classification is determined based on the Alternative UoM of the stock.

Putaway Task UoM Classification

• If a Putaway Warehouse Task (WT) is created at the product level, the system determines the appropriate Quantity Classification based on Stock UoM.
• If an HU Warehouse Task is created with a single product, the system calculates the Quantity Classification based on the HU content’s Alternative UoM.
• If multiple products are packed into a single HU, Quantity Classification cannot be determined based on UoM. Instead, HU Type from the packaging material is used for putaway classification.

Stock-Specific UoM for Outbound Delivery

Similar to Inbound Deliveries (IBD), the ERP Outbound Delivery (OBD) UoM is transferred to the EWM Outbound Delivery Order (ODO), provided that the ODO item type is configured accordingly.

However, unlike the inbound process, the Preferred UoM from the product master is not automatically applied in outbound deliveries.

Outbound Delivery with UoM Split

EWM enables updating the Item Stock-Specific UoM back to the ERP OBD.

For example:

• If a warehouse picks 1 PAL & 1 CV, EWM can create a UoM split in ODO (similar to Batch Split Items).
• If the setting "Update Delivery Item SUoM" is enabled, this UoM split is transferred back to the ERP OBD.
• This information can then be used to generate customer-specific documents such as packing lists and Shipment EDI ASN (Advanced Shipping Notice).

In case of Batch Managed product, UoM split can happen along with Batch split

Batch-Managed Products and UoM Split in Delivery | SAP Help Portal

Outbound Picking - Quantity Classification

Before EWM 9.0, EWM could only determine the Alt UoM by Packaging Specification. There needs to be a condition record of type 0WHT pointing towards the packaging specification for this product / Supply Chain Unit. There must be a level in the packaging specification which has as Warehouse Attributes the Quantity Classification of the storage type. If found, EWM should take over the UoM from the Packspec level into the WT.

By maintaining Quantity classification against the UoM, under Product UoM Attributes, we can determine the Picking sequence based on Pallet / Carton picks. Refer my previous blog on Zone based picking.

Key points

A thorough evaluation is essential prior to implementation, as the item type relevant settings apply to all warehouses within the EWM system. It is crucial to carefully assess dependencies on custom programs, labels, and forms before deploying the solution in warehouses that are operational without SUoM. Additionally, validate the accuracy of Product UoM against the packaging specifications, considering that an external vendor might ship 10 EA per carton, while another vendor might ship 8 EA per carton to a different distribution center.

Thnaks to the author Karthikeyan Prabaharan