EWM MES Integration: Receiving HUs in SAP EWM Explained

EWM - MES Direct Integration for Receiving HUs in EWM

EWM MES integration connects SAP Extended Warehouse Management with the manufacturing execution system, so that handling units produced on the shop floor can be received into the warehouse automatically. It defines who creates the HU and which document the receipt is booked against.

This article explains the two receiving scenarios SAP supports, the routes that connect the two systems, and the questions to answer before a project starts. The goal is to help you choose a setup that fits your production and warehouse processes.

What EWM MES integration means for receiving HUs

Receiving from production means that goods produced on the shop floor arrive in the warehouse as handling units. Without an integration, staff enter these receipts by hand. This slows the process and can make the stock in EWM differ from what the shop floor reports.

With an EWM MES integration, the receipt data flows automatically. The warehouse can plan put-away earlier, and the production team can see the status of each HU without asking the warehouse for updates.

Two receiving scenarios in SAP EWM

SAP describes two basic patterns for receiving from production:

ERP-triggered receiving: SAP ERP creates the production, process or planned order and can pre-plan the HUs. EWM receives the goods against these documents, and the shop floor confirms the quantities.
MES-based receiving: The MES drives the receipt. SAP Manufacturing Execution (SAP ME), a third-party MES, or SAP Manufacturing Integration and Intelligence (SAP MII) sends the receiving data to EWM.

Assigning each production line to one pattern keeps the document flow easy to trace. When two patterns run in the same plant, a receipt can be hard to follow if the team does not know which system started it.

How data flows between MES and EWM

SAP lists three routes for connecting EWM with the MES layer:

Through SAP ERP, which passes the order and HU data to both systems.
Directly from EWM to SAP ME.
Through the EWM API, which third-party MES platforms can call.

The route you choose also determines where the HU data is maintained. Settle it before you design the HU structure, because a later change of route usually means reworking the HU ID logic.

Which APIs does SAP provide for EWM MES integration?

There are several ways to implement EWM – MES direct integration for receiving HUs in EWM. One common approach is to use an interface or middleware solution that connects the two systems and allows for data exchange. This can be done using APIs (Application Programming Interfaces) or other integration tools, such as an integration platform as a service (iPaaS).

SAP provides a range of APIs (Application Programming Interfaces) that can be used to integrate SAP MES with SAP EWM. Some of the important APIs provided by SAP for this purpose include:

BAPI (Business Application Programming Interface): BAPIs are a set of predefined APIs that can be used to access and modify data in SAP systems. They can be used to exchange data between SAP MES and SAP EWM and to trigger specific business processes in the SAP systems.
IDoc (Intermediate Document): IDocs are a standardized format for exchanging data between SAP systems and other systems. They can be used to transfer data such as material and inventory information, production orders, and quality control results between SAP MES and SAP EWM.
RF (Radio Frequency) API: The RF API is a set of predefined APIs that can be used to access and modify data in SAP EWM using RF devices, such as RFID (Radio-Frequency Identification) scanners and handheld terminals. It can be used to support real-time data capture and material handling operations in the warehouse.
OData (Open Data Protocol): OData is a standardized protocol for querying and updating data over the web. It can be used to expose SAP data as REST (Representational State Transfer) APIs, which can be accessed and consumed by other systems, such as SAP MES.
Event-driven architecture (EDA): EDA is a design pattern that enables systems to communicate with each other by sending and receiving events. It can be used to set up real-time communication between SAP MES and SAP EWM and to trigger specific actions in response to specific events.

However, EWM MES integration can also be done with non-SAP systems. Some APIs provided by SAP for this situation are as follows:

/SCWM/MFG_CONSUME_ITEMS_EXT: Consumption of goods from production
/SCWM/MFG_READ_STOCK_EXT: Stock information from production
/SCWM/MFG_RECEIVE_HUS_EXT: Receive HUs
/SCWM/MFG_REVERSE_HUS_EXT: Reverse HUs
/SCWM/MFG_REVERSE_ITEMS_EXT: Consumption reversal from production
/SCWM/MFG_STAGE_EXT: External staging request for production

These are just a few examples of the APIs that can be used to integrate SAP MES and SAP EWM. The specific APIs that are used depend on the integration requirements and the capabilities of the systems involved.

Another option is to use a pre-built integration solution, such as a pre-configured interface or connector. This can be a faster and simpler option, as it requires less customization and setup. However, it may not offer as much flexibility as a custom interface or middleware solution.

Example: receiving pallets from a bottling line

Consider a bottling line that produces finished pallets across three shifts. The MES creates an HU for each pallet and sends the receipt to EWM.

EWM creates a receiving task, and the forklift driver scans the HU label at the storage location and places the pallet in a bin. The production team sees the pallet as received in the MES, and the warehouse sees the same HU in EWM. This is a simplified illustration, and the exact steps depend on your configuration.

Which route fits your plant?

Choose ERP-triggered receiving when production orders in SAP ERP already drive the shop floor and the MES mainly confirms progress.

Choose MES-based receiving when the shop floor creates the HUs and needs them in the warehouse right away. A third-party MES can connect through the EWM API. Check your current systems first, because the MES product often decides the route.

If you want to understand how HUs are managed in EWM before you design the receiving flow, read our guide to handling unit management in SAP EWM. For another integration of EWM with an external data source, see our article on RFID integration with SAP EWM, which explains how identification data reaches the warehouse.

Points to clarify before the project starts

Which system creates the HU ID, and which number range applies.
Whether each receipt is booked against an ERP order or a pre-planned HU.
How the warehouse handles failed receipts and reversals.
Whether staging and serialized products are part of the scope. The SAP sources we reviewed do not cover these in detail, so test them separately.

Steps for an EWM MES integration project

Map each production order type to a receiving scenario in EWM.
Define the HU structure and assign ownership of the HU ID.
Select the connection route: ERP, direct to SAP ME, or the EWM API.
Test receipts with real pallet labels on one pilot line.
Set up monitoring for failed receipts before going live on all lines.

SAP ME to SAP EWM

Frequently asked questions

Is SAP ME required for an EWM MES integration?

No. SAP ME is one option. Third-party MES platforms can connect through the EWM API, and SAP MII is also listed as an MES option.

Can EWM receive handling units from a third-party MES?

Yes. SAP lists the EWM API as the route for third-party MES systems to send receiving data to EWM.

What should you test first?

Start with one production order type on one pilot line. Check that each HU appears once in EWM and once in the MES, with the same ID and the same quantity.

Conclusion

An EWM MES integration for receiving HUs removes manual entry and keeps the warehouse and the shop floor on the same HU data. Start by choosing between ERP-triggered and MES-based receiving, then design the HU structure and test with real labels. This order keeps the project focused and reduces surprises at go-live.

References

Serhan Kurt

SAP TM – EWM Consultant
Serhan Kurt works on SAP TM and EWM projects covering transportation planning, freight management and warehouse processes. He is the author of “SAP TM: Senaryolar, Testler ve Uyarlamalar ile Birlikte”, the first book on SAP TM written in Turkish.