Exploring the World of Radio Frequency Applications in SAP EWM 

What are Radio Frequency Applications? 


RF applications are simple user interfaces, providing warehouse workers with small, precise amounts of information to ensure they can execute physical tasks step by step with minimal complexity. These applications are specifically designed to be run on handheld devices, equipped with barcode scanning functionalities, enabling users to seamlessly interact with the SAP Extended Warehouse Management (EWM) system eliminating the need for a PC or laptop. Radio Frequency (RF) applications have become indispensable tools for streamlining operations, enhancing accuracy, improving efficiency, reducing data entry errors, and allowing to process huge volumes of data. 


SAP EWM provides a comprehensive suite of approximately 80 RF transactions, each tailored to specific warehouse task and across various process. These tasks span across: 


  1. Inbound Processes: Including unloading, deconsolidation, putaway, and receiving of handling units. This facilitates the smooth transition of goods from arrival at the warehouse to their designated storage locations.
  2. Outbound Processes: Encompassing picking, packing, and loading operations. RF applications play a crucial role in orchestrating the efficient retrieval, packaging, and shipment of goods to customers or other destinations.
  1. Internal Processes: Such as inventory counting, ADHOC warehouse task creation, and system queries. These functionalities enable warehouse personnel to maintain accurate inventory records and swiftly address any discrepancies or inquiries that arise.

RF App Example – Receiving Handling Units 


To show an example of an RF app, we will take you through the process of receiving handling units in an inbound delivery. In SAP, RF apps can be tested using transaction /SCWM/RFUI. 


As a first step the warehouse user does is to select the relevant app – ‘Receive HU by ASN’ a following the menu path below:

Now, the user can start processing the delivery as shown in the process below: 

Once this process has been completed, all the goods have been packed (HUs created), unloaded and GR posted. All HUs are in the GR zone at this point of time. The Putaway task has been created and the HU can now be processed by other operators/resources. 


RF Apps  – Deployment Options 


SAP EWM offers a variety of applications spanning various categories. These applications are developed utilizing the RF Framework, DynPros, and ABAP. The RF Framework empowers developers to enhance existing apps or build entirely new ones. 


During the business process analysis stage, it becomes crucial to determine whether the standard applications adequately address the requirements of the business processes. If they do, they can be utilized “as is.” However, if they don’t, the standard application can serve as a template, allowing for adding new functionalities. In cases where there is a lack of standard application for customer’s business process, the creation of a new application becomes necessary. 


  1. Use standard application as is. 

If the standard app fits your business process you can use it as it is. Small tweaks can be done using customizing. This involves removing verification fields or buttons from UI screens. 


SAP also provides a tool to adjust the standard app screen sizes to your device of choice. A new device display profile gets created and the screens are converted. Although some of that process is automated it may still require manual intervention to ‘polish’ the screens if the UI elements don’t fit correctly. 


2. Enhancement of Standard RF  

Looking to customize a standard RF application in SAP EWM? This guide dives into several techniques that SAP EWM developers can leverage to enhance these apps and tailor them to your specific needs. 


a) BADI 

While Business Application Programming Interfaces (BADIs) offer a flexible way to customize SAP functionality, they have limited applicability for RF applications. In simpler terms, BADIs might not be the best fit for achieving your specific process within the Receive Handling Units RF app as there is not much choice and BADis are used sparingly. 


b) Standard function module wrapper 



  • You’re using a Receive Handling Units RF application. 
  • You want to capture the packaging material description during HU creation 


Desired Improvement: 

  • Add a dedicated field for “Packaging Material Description” on the HU creation screen (see attached screenshot). 



Here’s how to achieve this: 

  • Enhance the Data Structure – add a field for “Packaging Material Description” to the structure /SCWM/S_RF_REHU_HU. 
  • Utilize the screen enhancement wizard to introduce the new field on the HU creation screen. The wizard creates a dedicated function group and screen with the field, along with a configuration entry in SPRO 
  • Develop a custom wrapper function module (e.g., ZEWM_RF_REHU_PMSL_PAI) that calls the standard function module /SCWM/RF_REHU_PMSL_PAI. 
  • Update the RF customizing to direct the app towards the wrapper function module for step RHPMSL 
  • Implement Packaging Material Description Logic – within the wrapper function module, incorporate code to retrieve and display the packaging material description. 


Why This Approach is Preferred: 

This method prioritizes keeping your applications as close to the standard SAP configuration as possible. This offers several advantages: 

  • Reduced Maintenance: Any future correction notes or updates to the standard function module during system upgrades are less likely to disrupt your app’s functionality. 
  • Simplified Codebase: By leveraging existing functionalities, the code becomes cleaner and easier to maintain. 

Overall, this approach provides a robust and efficient way to achieve the desired outcome while minimizing potential issues down the road. 


c) Copy the standard function module 


  • You’re using a Receive Handling Units RF application.You want to capture the
  • Supplier Batch Number instead of SAP Batch Number for received products 
  • Standard RF Application, allows only to capture SAP Batch Number



Desired Improvement: 

  • Add a dedicated field for “Supplier Batch Number” in the Product scanning UI screen (see attached screenshot). 


This approach shares similar steps to the ‘wrapper function module’ method, but with a key difference. Unlike the previous method, the code can’t be simply inserted at the beginning or end within the wrapper. This is because the batch processing occurs in the middle of the existing code, interacting with posting functions. 


The only solution is to copy the standard function module /SCWM/RF_REHU_ITM_SCAN_PAI into a custom namespace (e.g., ZEWM_RF_REHU_ITM_SCAN_PAI). Then, you can modify the necessary lines of code to incorporate the supplier batch number into the posting functions. 


Drawbacks and Considerations 

While this method offers flexibility, it comes with a maintenance burden during SAP upgrades. Since you’ve essentially taken over the maintenance of the copied code, any fixes or improvements made by SAP to the original function module won’t be automatically applied to your custom version. This necessitates thorough testing of your modified code after each SAP upgrade to ensure continued functionality. 


3. Development of a new RF application 


Need a custom app to streamline your unique business process? 


Off-the-shelf apps might not always be the perfect fit. But don’t worry, building a new app from scratch is a viable option, especially if you involve key users in the design process from the beginning.  This upfront investment in design saves time and money later by preventing costly changes during testing. 


Here’s a roadmap to get you started: 

  • Map Out Your Processes: Clearly define the business workflows your app will support. Use flowcharts or diagrams to visualize the steps, decision points, and potential exceptions users might encounter. 
  • Design User-Friendly Screens: Create a basic layout (mockup or wireframe) that showcases where functionalities and data fields will be positioned. This helps ensure a smooth user experience. 
  • Craft User Stories and Test Cases: Think like your users! Describe all possible scenarios they might encounter while using the app. The more scenarios you consider, the better prepared your app will be for real-world use. Provide sample data for these scenarios so developers can thoroughly test the app’s functionality in the development system. 


Once you’ve completed these steps, you’ll have a comprehensive design document ready to hand off to a SAP EWM developer for coding. Which will follow the steps below: 


High level Development process 


  1. Create new RF Transaction  
  2. Create screens for each step based on the provided design. 
  3. Create PBO and PAI Function Modules 
  4. Configure the step and screen flow in RF Framework  
  5. Write the business logic inside the function modules 
  6. Add the up to RF Menu 
  7. Test the app in transaction /SCWM/RFUI



RF applications are transforming everyday warehouse operations, and SAP EWM offers a powerful suite of tools to take advantage. This blog post highlights how EWM provides off the shelf applications that can be readily implemented if they align with your existing workflows. But what if they don’t? No problem! SAP EWM developers can customize existing applications or create entirely new ones to perfectly suit your specific needs, maximizing efficiency across your warehouse activities.