SAP Extended Warehouse Management
RFID and EWM
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RF vs RFID
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RF (Radio Frequency) is a broad term for radio waves used in various applications like TV, Wi-Fi, and radar
RFID (Radio Frequency Identification) is a specific technology that uses RF to identify and track objects with embedded electronic tags and readers.
RF vs RFID
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RF (Radio Frequency) is a broad term for radio waves used in various applications like TV, Wi-Fi, and radar
RF vs RFID
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RFID (Radio Frequency Identification) is a specific technology that uses RF to identify and track objects with embedded electronic tags and readers.
RF vs RFID
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Key Differences at a Glance
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RFID History
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RFID technology began with military applications in the 1940s, particularly with World War II radar and the "identify friend or foe" (IFF) system, then developed into commercial uses in the 1960s and 1970s for theft prevention and tracking systems. Early RFID systems were researched by academic institutions and corporations in the 1970s for applications like automatic toll collection and assembly line automation. The 1980s saw international adoption for toll collection and personnel access, followed by the 1990s' critical standardization efforts and the commercialization of smaller, cheaper tags. The 2000s brought further development of standards like the UHF passive Class 1 Gen 2 standard, leading to broad retail adoption, especially after Walmart's push in 2005 and accelerated by the rise of omnichannel retail and the COVID-19 pandemic.
RFID History
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Early Concepts & Military Applications (1940s-1950s)
World War II (1940s): The concept of using radio waves for identification to distinguish friendly from enemy aircraft laid the groundwork for RFID technology.
Early Research (1948-1950s): Swedish scientist Harry Stockman's 1948 paper on "Communication by Means of Reflected Power" and work on microwave homodyne systems by researchers like D.B. Harris in the 1950s provided a foundation for later developments.
RFID History
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Early Commercial & Academic Applications (1960s-1970s)
Theft Prevention (1960s): Companies like Sensormatic began using simple tags for item tracking and theft deterrence.
Academic Research (1970s): Universities and companies invested in RFID research, focusing on applications such as automatic toll collection, animal tracking, and assembly-line automation.
First RFID License Plates (1975): The first RFID-transmitting license plate was created, a significant early commercial application.
RFID History
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Growth & Standardization (1980s-1990s)
International Adoption (1980s): RFID began to be used internationally for toll collection (e.g., Norway in 1986) and personnel access.
Toll Collection Systems: The creation of the E-Z Pass Interagency Group in 1990, which developed a standardized, compatible system for toll collection, was a major milestone.
Standardization Efforts (1990s): The 1990s saw significant efforts in standardizing RFID technology, with organizations like the Auto-ID Center at MIT playing a key role in developing accessible standards.
RFID History
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Commercial Expansion & Widespread Use (2000s-Present)
Standardization and Adoption: The 2000s saw the emergence of standards like the UHF passive Class 1 Gen 2 standard in 2004, paving the way for wider adoption.
Retail Revolution: Walmart popularized item-level tagging in the mid-2000s, significantly impacting inventory management.
Omnichannel Shift: The transition to omnichannel retail, emphasizing "buy online, pick up in store", made RFID's ability to provide real-time inventory visibility indispensable, with the COVID-19 pandemic further accelerating this need.
Continued Growth: Today, RFID is used across various industries, from logistics and aerospace to biomedical and retail, with ongoing efforts to reduce costs and improve user-friendliness.
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RFID in SAP
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RFID integration with SAP systems, particularly SAP Extended Warehouse Management (EWM), automates the identification, control, and tracking of inventory and handling units using RFID tags. This technology provides real-time data for optimized warehouse processes, enhanced inventory accuracy, improved traceability, and automated data entry, reducing manual errors and labor costs. Key components include compatible RFID hardware, middleware for data processing, and configuration within SAP's material master and EWM to link RFID tag IDs to inventory items.
RFID in SAP
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Key Benefits
Real-Time Visibility: Gain live updates on stock levels and item locations within the supply chain.
Warehouse Automation: Integrate with automation systems like robots and conveyors to support autonomous operations.
Reduced Manual Effort: Eliminate manual data entry and reduce the need for direct line-of-sight scanning, speeding up tasks like inventory counting.
Enhanced Accuracy: Improve inventory accuracy by minimizing errors associated with manual processes.
Counterfeit Prevention: Use RFID's encrypted identifiers to verify product authenticity and prevent counterfeits.
Contact-Free Operation: RFID allows for contact-free identification of items, which is particularly useful in densely packed warehouses.
RFID in SAP
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How RFID Integration Works with SAP
Hardware Selection: Choose UHF RFID readers compliant with standards like EPC Gen2v2 and capable of connecting with SAP's IoT framework, often via OPC UA or REST APIs.
Middleware Deployment: Implement middleware to receive raw RFID data, filter, aggregate, and format it into a structure that SAP can understand.
SAP Configuration: Material Master Setup: Assign unique RFID tag IDs as custom fields in SAP's material master (transaction MM01/MM02) and link them to specific batches or serial numbers.
IDoc/BAPI Integration: Utilize SAP's Intermediate Documents (IDocs) or Business Application Programming Interfaces (BAPIs) to transfer the processed RFID data into the SAP system.
EWM Integration: For warehouse processes, SAP EWM can leverage this RFID data to track and control products and handling units.
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Issues of RFID: Technical Data Issues
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Technical & Data Issues
Signal Interference: Metal, liquids, and other radio frequency devices can interfere with RFID signals, leading to missed scans and inaccurate inventory data.
Synchronization Gaps: Incorrect synchronization between the RFID system and SAP EWM can create unreliable stock visibility and cause operational disruptions.
Data Discrepancies: Poor signal capture, reader placement, and tag issues can result in discrepancies between physical stock and system records, impacting planning and decision-making.
Issues of RFID: Technical Data Issues
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Solutions include
Performing site surveys: Strategically positioning antennas away from metal, adjusting reader power, using shielding materials
Appropriate tag selection: Selecting appropriate tags (on-metal, waterproof) and frequencies (UHF, LF/HF)
Avoid signal congestion: Configure your readers to avoid congested frequencies using frequency hopping and dense reader mode, minimize the presence of other wireless devices like Wi-Fi routers, and use RFID-shielded enclosures when necessary.
Software: Implementing software features like frequency hopping, and employing repeaters to extend signal range.
Issues of RFID: Technical Data Issues
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1. Adjust Tag and Antenna Characteristics
Use specialized tags: For metal surfaces, use on-metal RFID tags that are designed to mitigate metal interference. For liquids, use near-field antennas or tags designed to handle moisture.
Adjust tag placement: Place tags in a consistent, visible location on items and avoid placing them on seams, edges, or near foil stamps on books.
Optimize antenna placement: Mount antennas at least 30–50 cm (20 inches) away from metal and liquid surfaces to reduce signal absorption and reflections.
Angle antennas: Tilt antennas 15-30° downward to focus the signal on the target items and reduce reflections from nearby machinery or walls.
Choose the right antenna: Circular-polarized antennas are effective in metal-rich environments like warehouses with steel shelves.
Issues of RFID: Technical Data Issues
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2. Manage Reader and System Settings
Enable frequency hopping: Utilize Frequency Hopping Spread Spectrum (FHSS) technology to allow the reader to dynamically change frequencies and avoid congested channels, especially for UHF readers.
Use dense reader mode: Configure readers to prevent cross-talk and interference in multi-reader setups.
Optimize reader power: In crowded environments, reduce the transmit power of your RFID readers to minimize signal overlap.
Issues of RFID: Technical Data Issues
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3. Control the Environment
Separate devices: Keep RFID systems at least 3 meters (10 feet) away from other wireless devices, such as Wi-Fi routers and Bluetooth devices, that operate on similar frequencies.
Shield sensitive areas: Use RFID-shielded enclosures or materials around sensitive equipment or areas with high interference to block unwanted signals.
Minimize obstacles: Reduce the number of metal and liquid obstacles in the environment to improve signal penetration and reduce reflections.
Issues of RFID: Technical Data Issues
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4. Plan and Test the System
Conduct an RF spectrum audit: Before deployment, audit the surrounding environment to identify existing sources of wireless interference.
Perform pilot testing: Conduct a pilot installation to measure system performance in the planned environment and make necessary adjustments before full deployment.
Consult experts: If you continue to experience interference issues, contact RFID specialists for professional consulting and troubleshooting.
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Challenges in RFID in SAP EWM
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RFID integration issues with SAP are often a result of technical challenges like signal interference from metal and liquids, poor reader placement, and environmental factors, which lead to inaccurate data and visibility gaps. However, integration problems are also heavily rooted in gaps in real-time data synchronization between the RFID system and SAP EWM (Extended Warehouse Management) and insufficient manual intervention for error correction. Other factors include the high cost of RFID systems, a lack of standardization, and data security concerns that make it difficult to implement end-to-end solutions.
Challenges in RFID in SAP EWM
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Technical & Environmental Challenges
Signal Interference: Metal, water, and other materials can block or distort RFID signals, leading to missed scans and inaccurate data.
Reader Placement & Signal Capture: Poor placement of readers and inadequate signal capture can result in unreliable tracking.
Tag Issues: Damaged or improperly encoded tags will cause scanning failures and data discrepancies.
Environmental Factors: Temperature, humidity, and exposure to chemicals can affect RFID tag and reader performance.
Challenges in RFID in SAP EWM
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Integration & System Synchronization Issues
Data Synchronization: Inaccurate or delayed data synchronization between RFID hardware and SAP EWM creates a gap in real-time inventory visibility.
RF Device Interface Design: UI on the Hand-held Device must be clear and concise.
Manual Intervention: Gaps in automated integration often require manual data entry and error correction, reducing efficiency and introducing delays.
Lack of End-to-End Integration: Deploying RFID as a point solution without integrating it with the wider SAP system or across the entire value chain results in a fragmented system that fails to provide true traceability.
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SAP RFID support for EPC
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Electronic Product Codes (EPC) is highly recommended and is a standard practice for SAP RFID integration with EWM (Extended Warehouse Management) because it provides a standardized, unique identifier for physical objects, which is crucial for accurate tracking and management within the warehouse and across the supply chain. SAP's Auto-ID Infrastructure (AII) component, which is often used with EWM, supports the use of EPCs and provides the framework for their integration with warehouse processes.
SAP RFID support for EPC
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Why EPCs are Recommended:
Standardization: EPCs are a widely adopted standard for RFID tag encoding, ensuring global interoperability and consistent data formats across different systems and partners.
Uniqueness: Each physical item can be assigned a unique EPC, allowing for precise identification and tracking of individual items, cases, or pallets.
Flexibility: The EPC standard is flexible and can be linked with other dynamic data, such as manufacturing dates or origin, providing rich contextual information for the identified products.
SAP Support: SAP provides specific components like SAP Auto-ID Infrastructure and SAP OER (Object Event Repository) that are designed to handle and manage EPC data, ensuring seamless integration with SAP EWM.
Improved Operations: Using EPCs with RFID enables real-time inventory accuracy, faster order fulfillment, and enhanced supply chain visibility by automating data collection and processing.
SAP RFID support for EPC
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How it Works in SAP EWM:
RFID Hardware and Middleware: RFID readers, compliant with EPC standards like EPC Gen2v2, collect data from RFID tags on products.
RFID middleware filters and formats this data before it's sent to SAP.
SAP Auto-ID Infrastructure (AII): This component receives the RFID data and processes the EPC information.
Integration with SAP EWM: The EPC data is linked to handling units (HUs) and other master data within SAP EWM.
Real-time Visibility: EWM uses the EPCs to track items in real-time, leading to improved inventory management and operational efficiency.
SAP RFID support for EPC
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RFID support for EPC is not new, it was already there in SAP EWM 5.1. For using it SAP EWM should be combined with SAP AII (Auto ID Infrastructure).
This is a separate piece of software running on Netweaver stack and connects to SAP EWM through RFC/ web services. An overview of functionalities can be found in the SAP Help (https://help.sap.com/docs/SAP_EXTENDED_WAREHOUSE_MANAGEMENT/3d97bec9bf1649099384bb8167df3cf2/cac9cb53ad377114e10000000a174cb4.html?locale=en-US).
SAP RFID support for EPC
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Technical Details of SAP EWM RFID
There are a few objects to know when working with RFID in SAP EWM.
Function groups
The function group /SCWM/RFID has one function module /SCWM/RFID_ACTION. This is the heart for performing all RFID actions. It is RFC enabled and called by AII. Likewise I used it to call it directly in a test program as I had no AII at hand. You can perform the following actions with it:
SAP RFID support for EPC
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Classes
Classes and their methods are used by the above FM for all actions.
information stored on RFID tags used for tracking and identification within the warehouse.
SAP RFID support for EPC
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Views
/SCWM/V_EPC_RSRC. You use this view to maintain the assignment of a regular EWM resource to an EPC code which you want to see associated to a RFID device and to a printer. I couldn't find this in the IMG so I found it worth mentioning.
SAP RFID support for EPC
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Persistence layer
There are two tables where the data is stored: