Warehouse Management Systems vs. Warehouse Control Systems
By Thomas R. Cutler, President & CEO, TR Cutler, Inc.
Although there is some functionality overlap, the differences between Warehouse Management Systems (WMS) and Warehouse Control Systems (WCS) can be significant. Without a firm grasp on these concepts, companies that rely on the day-to-day movement of product in and out of a distribution center or warehouse often find themselves at a distinct disadvantage.
"A lot of companies probably don't know the difference in a WMS and a WCS system,' says Jerry List, vice president of QC Software in Cincinnati, OH. "To put it simply, the WMS plans a weekly activity forecast, based on such factors as statistics, trends, and so forth. And a WCS acts like a floor supervisor, working in real time to get the job done by the most effective means."
WMS, for example, can tell the system hours in advance it's going to need five of SKUa and five of SKUb. But by the time it acts, other considerations may have come in to play and create a conveyor logjam.' A WCS can prevent that problem from happening by working in real time and adapting to the situation on the spot,' says List. "It can make a last-minute decision based on current activity and operational status."
Warehouse Management Systems began to flourish in the 1980s, with the introduction of mini-computers. Companies back then were aware when the time was right to implement a WMS into their distribution center operation, according to Kevin Tedford of KT Consulting in Marion, OH, who has worked with warehouse management systems for the past fourteen years.
"Businesses saw the need for a warehouse management system when they started hitting certain 'pain points,' " explains Tedford. "This usually happened when they saw the costs of delivery rising, labor costs on the increase and a need to control inventory and keep track of what their people were doing. It was the moment they first began to realize, ' We have no control!' "
What the warehouse management system did was return that control to the distribution center supervisor. "The greatest advantage was it brought back inventory control and accuracy,' he says. "And brought it back to a super-high level, so much so that companies could now exceed their customers' highest expectations, performing tasks in hours that at one time may have taken days or even weeks."
Since 2000, the increased need to move more products faster and in a shorter amount of time, and do it with fewer workers, accelerated technology.
The simple act of walking up and down a warehouse aisle picking products from a paper order was replaced by high-tech pick-to-light and pick-to-voice technology. The pace quickened, products increased, as well as the need for better order verification and order fulfillment.
"Suddenly, there was a 'better, faster, cheaper' mentality prevalent in the warehouse,' says QC Software's List. "And the old-school WMS mentality was being challenged. As warehouse management systems began to take on more responsibilities, a void was created which warehouse control systems nicely filled, especially as systems became faster and real time demands were established."
Over the last ten years, distribution centers saw an increasing need for improved warehouse communications, from the WMS to the WCS to the conveyor to the customer, according to Jerry Lovell, senior electrical project engineer for TriFactor, LLC, a material systems integrator based in Lakeland, Florida.
"Companies are now able to see the status of their material handling system in real-time with all information up-to-date," Lovell said. Today they can make a hard decision right on the spot, where ten years ago they more or less had to guess. They know right away if something is wrong and they can react with a faster response time. I once had a company executive tell me that having a WCS system in his warehouse "Lets me sleep at night.''
Jerry List agrees. "A warehouse control system enables you to utilize new technology, which allows greater flexibility on the plant floor," he says. "It's an integrating tool that ties everything together. Think of equipment like conveyors and picking technology as building blocks. The WCS is the mortar between the blocks that holds everything together.
"The perfect candidate for a WCS is the company that utilizes a lot of material handling devices and needs to put a lot of decision points in their system and be able to balance them all in an efficient manner," offers List.
List points out that another key advantage to the WCS is location. When faced with running multiple warehouses, the warehouse management system is not physically located in the warehouse, he says. "But even if there's a network-wide problem, the warehouse control systems, being situated in the warehouse, can keep the operation up and running."
Not every operation needs or requires a warehouse control system, particularly those that hand pick from paper and pallets, or have a minimal number of product lines and/or SKUs. But according to a white paper produced by List and QC Software, there are some very real telltale signs that there could be a WCS in your company's future: * The current system is inefficient and takes too long to get a product out the door.
To put the difference between WMS and WCS in simple terms, WMS is a planning system, WCS is an execution system. The WMS collects a vast amount of information, such as inventory data, customer orders and historical data, and then processes it in a non-real time mode, mapping out a workload plan for what needs to be done on the warehouse floor on a day-to-day basis. But it is the warehouse control system that has final control over the large amount of information being placed by the WMS and reacts to "actual' events on the warehouse floor.
According to Jerry List, a company may want to explore the possibility of adding a WCS if they have the following characteristics:
- More than $50M in sales.
- A warehouse larger than 100,000 square feet.
- A conveyor system with multiple sortation points.
- More than an average of three SKUs per order.
- Greater than 1,000 orders per day.
TriFactor's Jerry Lovell agrees. "WMS and WCS is an important piece of the technology puzzle. There's a consistency factor knowing that technology can perform the same tasks, over and over, eliminating the possibility of human error. Technology is reliability. WMS and WCS give you the peace of mind of knowing that your system is using proven technology. If your competition has it, and you don't, then you are at a definite competitive disadvantage."
The author of this piece, Thomas R. Cutler, is the President & CEO of Fort Lauderdale, Florida-based, TR Cutler, Inc. Cutler is the founder of the Manufacturing Media Consortium of three thousand journalists and editors writing about trends in manufacturing. Cutler is a member of the Society of Professional Journalists, Online News Association, American Society of Business Publication Editors, Committee of Concerned Journalists, Society of American Business Editors and Writers, as well as author of more than 300 feature articles annually regarding the manufacturing sector.