What is a Warehouse Control System (WCS)?

A warehouse control system (WCS) is software application that operates at the lowest level of abstraction within a warehouse or distribution center (DC).  While warehouse management systems (WMS) interact at the highest level, integrating with enterprise resource planning (ERP) systems, managing labor, and more, the WCS interacts at the lowest level, interacting directly with material handling equipment (MHE). In some cases, the warehouse execution system (WES) bridges the gap between the WMS and WCS.

The boundaries that separate the WMS, the warehouse execution system (WES), and WCS are blurred, with modern WMS solutions adding more and more lower-level features to their portfolio.  Similarly, WES solutions can extend the lowest level, supplanting the need for a WCS, as well as take on more and more higher-level tasks typically reserved for a WMS.  In a typical DC, all or most of the tasks in Figure 1 must be managed and directed, somehow.  How tasks are divided between software solutions will depend on the systems solution provider and the MHE utilized.

A key aspect of a warehouse control system is that it interacts with the WMS and material handling equipment in real time.  While the WMS may queue up a variety of orders to be picked, and may even optimize the sequence of those tasks, it is the WCS that actually interacts with the conveyor system to ensure that an order carton is diverted to the proper shipping lane or packout station.  All of this happens in real time, with the WCS receiving barcode data from the in-line scanner, processing it, querying the WMS or a database for the shipping destination, and then instructing the conveyor system to activate the proper divert in sync with the carton's arrival (see Figure 2).  In this case, the WCS completes its tasks in the time between the carton passing through the scanner and reaching the sorter.

Why do I need a WCS?

As consumer expectations for delivery time get shorter and shorter the need for improvements in DC efficiency is only increasing.   The average expected delivery time for e-commerce is less than 3 days. Furthermore, current trends suggest that many consumers prioritize delivery expediency over price reduction.  

The bottom line is that distribution centers need to be more efficient. This is typically achieved by utilizing more automation whether via software, hardware, or both.  Even “manual” processes are often aided by some level of automation, whether it be pick-to-light or utilizing mobile devices for scanning and task direction.  It may be possible and even effective to integrate a few systems without the use of a WCS, like a simple pick-to-light system with a scanner and some conveyor, using some peer-to-peer (P2P) communication.  Such an arrangement, however, becomes more complex as additional devices and systems are added, necessitating centralized control which can be provided by a warehouse control system (see Figure 3).

Examples of ad-hoc control with peer-to-peer connections vs centralized control with a WCS.  Lines with arrows denote flows of communication and control

The Core Functions of WCS

At the most fundamental level, a warehouse control system acts as a conductor of a symphony, cueing all of the actions occurring on the warehouse floor in real time.  Consequently, a critical part of any WCS is its ability to integrate with MHE.  The WCS must communicate with and control a wide array of devices from programmable logic controllers (PLC) in a conveyor system to automated guided vehicles (AGV) and their management software to printers and scanners at workstations.   This means that the WCS must be capable of interacting with devices and their control software via APIs, industrial control protocols such as Profinet and EtherNet/IP, sockets over ethernet, RS-232 and RS-485, and more.  

Additionally, acting as a middle-man between the MHE and WMS, the WCS must be capable of integrating with the WMS.  In some cases, the WMS and WCS are separate solutions from different providers and the ability of the two to interact seamlessly is a necessity.  As a result, the WCS must be capable of interacting with a variety of protocols such as RESTful, RPC, SOAP APIs, message services, etc.

Considerations for Implementing WCS

The selection of a warehouse control system is typically downstream of the warehouse management system.  Modern WMS systems include varying degrees of capability, some providing all of the features of a traditional WCS.  It is important to consider that the systems employed are capable of enabling the tasks required within the DC.  Some combination of WMS, WES, and WCS may be required depending on the business needs and the MHE employed.  

Another consideration when deploying a WCS is future growth.  How will the business change over time?  Will the same WMS be in place in the future?  Will the WCS work with another WMS?  How easily can the WCS scale to handle higher throughput and control future MHE that might be added to the operation?  These are some of the basic questions that must be considered before implementing a WCS.

Beyond the basic functionality, it is necessary to understand the capabilities, features, and limitations of every system and device in the operation in order to properly control it.  It is one thing to speak the same language as a coworker; knowing what instructions to give that coworker is equally important.  Given the myriad solutions for WMS, conveyor, sortation, AGVs, goods-to-person systems (GtP), pick-to-light, etc. in the marketplace, selecting an experienced, unbiased systems integrator is crucial. A capable integration partner will have the expertise required to navigate the aforementioned considerations, the experience to navigate the technology landscape, and the insight to plan for future flexibility resulting in maximal efficiency and return on investment. 

Future Trends in WCS

The high-end software marketplace continues to trend towards full-suite subscription solutions, where a single provider provides a modular system that includes features of a traditional WMS and WCS.  These products are typically cloud-based services though the lowest-level applications, those which perform the WCS tasks, are often locally hosted for purposes of speed/latency.

There still is a market, though, for separate WMS and WCS/WES solutions, and every operation will have different needs.  By working with clients across industries and across the spectrum of size and throughput, at Maveneer we are staying ahead of the curve by taking the best products and experiences and adding them to our portfolio.   

Conclusion

The warehouse control system is playing a larger role in DCs as they become faster, more automated, and employ a wider variety of equipment and systems.  However, the WCS is also increasingly being bundled into WMS offerings, especially from the largest providers.

When contemplating whether or not to utilize a WCS, or which WCS to select, it is important to consider the holistic needs of the business and the operation on the warehouse floor.  What are the tasks and outputs required to succeed, from the moment an order is received to the moment it leaves on a truck?  Some tasks may be handled by the WMS, others by a WCS or WES.  At Maveneer it is our job to help you figure it all out and, as a supplier-agnostic integrator, we explore all possibilities to ensure that your operation thrives.

If you have an application or problem related to warehouse systems or control, or you’re looking to improve your current operation or even design a new facility, speak with a Maveneer today.