Introduction

In this blog post, we dive into the distinct responsibilities of Warehouse Management Systems (WMS), Warehouse Execution Systems (WES), and Warehousing Control Systems (WCS), highlighting their unique functionalities and providing details about their advantages. More importantly, we want to discuss why the terms are often interchanged and misinterpreted. It seems like every vendor provides their own definitions for each out there in the market.

In the dynamic landscape of modern logistics, effective warehouse management is crucial for businesses aiming to optimize their operations and meet customer demands efficiently. Advanced technological solutions that streamline warehouse processes are crucial to achieving this optimization. WMS, WES, and WCS stand out as essential components among these solutions.

Warehouse Management System (WMS)

A Warehouse Management System (WMS) serves as the central system of any warehouse, managing and optimizing various processes to ensure smooth operations. Its primary responsibilities include planning activities around receiving and shipping goods, inventory management, order processing, and warehouse optimization. WMS software facilitates tasks such as receiving, putaway, picking, packing, and shipping while also providing visibility into inventory levels and warehousing activities. A WMS enables businesses to enhance inventory accuracy, improve order fulfillment speed, and optimize warehouse layout for maximum efficiency by automating these processes and providing accurate data insights.

Warehousing Control System (WCS)

Warehousing Control Systems (WCS) focus on controlling and optimizing automated equipment and material handling systems. A WCS is typically provided by the vendor of the warehouse automation equipment, thus leveraging its native communication to expose interfaces to the other elements in the landscape in the form of software APIs. It is responsible for translating high-level directives from WMS into actionable commands for material handling equipment (MHE), such as conveyors, sorters, and automated storage and retrieval systems (AS/RS). Its key functionalities include material routing, task prioritization, efficient locating and allocating of goods, and equipment control. A WCS ensures that tasks are executed most efficiently by coordinating the movement of its active parts (e.g., robot arms, bots, conveyor outfeed lanes) to deliver goods to the end location with as few movements as possible.

Warehouse Execution System (WES)

Complementing the functionalities of a WMS, a Warehouse Execution System (WES) focuses on the real-time control and orchestration of warehousing tasks and resources within the warehouse. Unlike a WMS, which primarily deals with high-level warehouse processes, a WES operates at a granular level, managing tasks such as equipment scheduling, task interleaving, and order allocation. By dynamically allocating resources and optimizing task sequences based on real-time conditions, a WES ensures efficient material flow throughout the warehouse, minimizing bottlenecks and maximizing throughput. Additionally, a WES often collects large volumes of data from various systems in the warehouse. It provides high-quality data insight with added predictive abilities to alert equipment failures and potential bottlenecks. All the above-mentioned capabilities are possible because a WES is, on the other side, constantly communicating with a WCS to deliver to each warehousing automated equipment the next task to execute, but also to understand what each component is currently executing and in what state it is. We can consider a WES as a bridge between a WMS and a WCS.

Side-by-side comparison

While a WMS, WES, and WCS serve distinct roles within the warehouse ecosystem, they are interconnected and mutually supportive, working together to optimize warehouse operations. The WMS focuses on managing inventory and warehouse processes at a high level, while the WES drills into the real-time control and orchestration of tasks and resources. The WCS is the lowest layer closest to the warehouse hardware and its programmable logic controllers (PLC), ensuring seamless communication and synchronization between warehouse management functions and physical equipment.

All of this sounds very reasonable. In theory. However, when you walk through warehouses, talk to key stakeholders, and try to map their requirements into architectural models, it gets very complicated very quickly. Boundaries between the systems start moving and getting blurred from time to time.

Warehouse Execution System and different types of equipment

For a WES to orchestrate tasks and resources in its warehousing ecosystem, it must be capable of understanding the abilities of each automated equipment installed and integrate and "talk” to each individual WCS in the warehouse. This means the WES requires high intelligence and flexibility to orchestrate tasks effectively across diverse warehouse equipment types. Therefore, there are two crucial groups of capabilities that a WES must provide:

• Maintain profiles of each type of equipment in the warehouse, including specifications, functionalities, and limitations. This information lets the system make informed decisions about task assignments and resource allocation.
• Implement rule-based decision-making algorithms to determine the most efficient way to allocate tasks and resources based on predefined rules and priorities. These rules consider factors such as task urgency, equipment availability, capacity constraints, and operational objectives.

Black-box warehousing automation solution

In the context of black-box automated storage and retrieval solutions, the WMS and WCS play distinct yet complementary roles in ensuring the efficient operation of the warehouse.

The WMS is responsible for managing inventory within the warehouse. It keeps track of stock levels, locations, and movement history. When integrated with automated storage systems, the WMS updates inventory records in real time as the system stores or retrieves items. The WMS assigns tasks to warehouse personnel and equipment. It prioritizes tasks based on deadlines, order types, and resource availability. For automated storage systems, the WMS generates instructions for WCS to execute tasks such as picking, replenishment, and putaway.

The WCS is responsible for controlling automated equipment within the warehouse, such as an AS/RS, conveyor systems, robotic arms, and sortation systems. It coordinates the movement of equipment to execute tasks efficiently. The WCS receives instructions from the WMS and translates them into commands for automated equipment. It manages tasks such as storing items in designated locations, retrieving items for orders, and transporting goods between different zones within the warehouse. The WCS also continuously monitors equipment status and adjusts operations in real-time to optimize efficiency. It may reassign tasks, adjust routing, or prioritize certain operations based on changing conditions such as equipment failures or traffic congestion.

During every implementation, two crucial questions arise and more or less drive in which direction the solution's architecture will go:

• Which system will manage the locations from the automated warehouse, and to what level of details will inventory in the automated warehouse be tracked?
• Which system will be responsible for tracking the on-hand inventory from the automated warehouse?

We suggest using a black-box automated storage solution, which inherently means the automated warehouse is represented as a single physical location in WMS. With this approach, the WMS only knows the total inventory of certain products in automated storage regardless of more detailed tracking details, e.g., locations or license plates.

However, the challenge with this solution is that the WCS often can't track the inventory by license plates. It makes sense since WCS is natively a solution that excels at instructing automated equipment about the next task. Anyway, there are two ways to address this issue:

• The WMS takes over responsibility for detailed inventory on-hand tracking for an automated warehouse. This approach moves the workload of hosting additional inventory on-hand data and processing inventory transactions to WMS, making this solution a white-box solution. It is definitely not an architectural approach that we would recommend implementing.
• The other approach would be to enrich the WCS by extending it with a certain level of intelligence and data. This way, the component of the WMS, which is responsible for handling operations in the automated warehouse, remains very simple. On the other hand, the WCS embraces more than it is supposed to by definition. One could say that the WCS, by taking over new responsibilities, becomes "the brains" of the warehousing operations. Furthermore, this additional logic and data could be removed from the WCS and encapsulated in a separate solution. Let's call it the WES. This way, we keep the warehouse automation solution black-boxed, at least from the WMS perspective.

Is WES just another name for existing solutions?

A WES can theoretically replace the WMS and WCS by managing warehouse inventory records and overseeing warehousing automation. The WMS, which helps with automation, could be called WES. But really, it's just a customized mix of tools designed to fit what you need. When deciding on a software system for your business, focusing on what you need will get you a better and cheaper solution than just buying something off the shelf.

The crucial aspect in selecting the most suitable system for your facility isn't about embracing a new name promising a blend of solutions but instead opting for a modularized solution that enables you to define the necessary functionality. A WMS and WCS are not universally applicable products. WMS and WCS providers must collaborate with their customers to identify the specific system aspects required for each scenario.

Conclusion

While each system has distinct responsibilities, their interchangeable use and misinterpretation persist in the market. Effective warehouse management is vital in today's dynamic logistics landscape, necessitating the adoption of advanced technological solutions. A WMS primarily oversees high-level processes, a WES orchestrates real-time task allocation, and a WCS controls automated equipment. Challenges arise in integrating these systems, especially in orchestrating tasks across diverse equipment types. While theoretically, a WES may replace a WMS and WCS by managing inventory and automation, the complexity of business requirements necessitates tailored, modular solutions rather than off-the-shelf options. Collaboration between warehousing specialists and end users is crucial to align solutions with specific scenarios, ensuring optimal warehouse operations.

Would you like to gain deeper insights into incorporating these topics with Dynamics 365 Supply Chain Management and its material handling equipment integration solution? Reach out to our team for expert guidance from specialized professionals in the field.