Supply chain software: Warehouse control systems find their place

You know the old saying: caught between a rock and a hard place. That’s sort of where warehouse control systems (WCS) have traditionally found themselves in the supply chain. They sat somewhere between a warehouse management system (WMS) and automated materials handling equipment and systems. For the most part, WMS systems did the heavy lifting when it came to managing inventory, planning waves and batches of orders and directing the activities on the floor. The WCS, meanwhile, pretty much did what it was told: It took a queue of orders from the WMS and made sure the conveyors or sortation systems turned on and off in time to route product to the right location in a facility.

In the conventional warehouse, the WMS is still the head honcho, directing the activities on the warehouse floor. But as order fulfillment requirements become more complex and more distribution centers adopt automation, a new breed of WCS is emerging that blurs the line between the WCS systems of old and WMS, says Jerry List, vice president of QC Software (www.qcsoftware.com), a Cincinnati-based provider of WCS. “The WCS used to be an equipment manager,” says List. “Today, it’s overlapping into WMS territory by balancing the workload on the floor.”

The evolution from equipment manager to order fulfillment manager has led to not only a new breed of WCS, but also the emergence of a new breed of WCS provider. Most WCS systems are still provided by the leading OEMs, including SSI Shaefer, Daifuku, Dematic, HK Systems, Witron and Swisslog, a handful of vendor neutral providers like QC Software are emerging. And just as the WMS evolved from a custom-coded to packaged solution, companies like QC Software are also developing packaged WCS solutions.

What does this new breed of WCS do? In today’s automated warehouse, the WMS “has been promoted more to a managerial role and isn’t as tied to the day-to-day operations,” says list. “It’s becoming more of a planning system, looking at trends, forecasting and communicating with the ERP.”

The WCS, meanwhile, “can now do the wave planning and even some of the conventional picking that a WMS used to control,” says List. The best WCS systems – those that are the equivalent of a Tier 1 WMS – can also do a real-time allocation of work on the floor by first determining the optimum pick location based on the activity on the floor and then reporting what has occurred back to the WMS. “A WCS still doesn’t do things like labor management or slotting,” says List. “Those are still the role of a WMS.”

In fact, some customers have jumped right from an ERP-controlled warehouse to a WCS-controlled warehouse without adding a WMS. “One of our customers used their ERP system to manage RF-directed picking,” says List. “As business picked up, they added a conveyor system, zone diverts and a WCS. We even were able to add tools to direct the lift truck drivers and carts.” The customer did eventually put in a WMS a few years ago because they needed more sophisticated slotting. “We were able to buy them a number of years before they had to make that investment,” says List.

How then to make the distinction. “If you’re looking at an automated warehouse, what we suggest is that you look at whether a process requires a modification,” says List. “If so, we suggest doing the activity in the WCS because it’s easier to modify. If it’s a modification on a WMS, that can increase the cost of an upgrade.”