In the latest of a series of articles from members of the Automated Material Handling Systems Association (AMHSA), John Barton, Managing Director of Keymas Ltd, examines warehouse management systems.

 At the fall of France in 1940, the French had over two thousand modern fighter planes - more than twice the number deployed by the victorious Luftwaffe. The problem was that the French administration didn’t know where most of them were. The German Blitzkrieg attack had led many local commanders in France to make tactical decisions to move aircraft, men and equipment south, away from the invaders. These parochial decisions had no easy way of becoming known centrally, with the result being chaos and capitulation. Acolytes of the military theorist Carl von Clausewitz will know of the parallels that exist between military and business strategies. If only the French had had a management system that allowed lower-level local commanders to input information, then those at the top could have made decisions and acted upon it.

WMS is not the full answer

In the modern logistics industry, we have software information systems known as warehouse management systems (WMS), which perform a vital role but are not the full answer in a dynamic business environment. Much WMS software is highly sophisticated and its strength is, in essence, that all information goes into the centre and the WMS ‘runs the business’ from the top down. Perhaps it should not be called a warehouse management system at all, but rather a business management system, as its remit is so wide. There can be a similarity between a modern WMS and what happened in France in 1940, if the lower levels cannot input information. Such input is normally achieved by utilising subsystems that run particular aspects of the logistics solution. The strength of WMS - its central input of information - can also be a weakness, if relevant information cannot be input at these lower levels. Important considerations here include: if there is a problem centrally, will the whole system shut down? Can subsystems add information that the central WMS will accept?

Subsystem control is key

Let’s call these subsystems SMWs (Systems that Manage the actual Warehouse) and let’s visualise them as a local warehouse foreman or manager. Local management makes decisions based on transient factors such as heavy snowfall or a local dock strike - not the distant board of directors. With local knowledge, the site management is best placed to make such tactical decisions. So the ideal logistics solution is one with a WMS that looks after the strategic, commercial aspects of the business - such as the databases, the commercial parameters and the financial paperwork to cover invoicing and billing. Under this, one should consider having tactical subsystems that look up to the main WMS and make it an effective and efficient system as a whole. The advantage of this kind of setup is that there is less electronic traffic on the system in terms of information interchange. The WMS does not have to cope with all the minutiae of logistical movements.

Plan subsystem control at the outset

When considering WMS, one size definitely does not fit all! Many subsystems that will each control a material flow function - such as a miniload crane or an AGV - can be added onto the WMS until it is a comfortable fit for the business at its local level. We could therefore prophesy that the best solution will normally be an efficient, strategic WMS supported by as many tactical machine control subsystems (SMWs) as are required to make the whole system buzz. To extend this to a rule of thumb, one needs to consider the tactical subsystems at the same time as the strategic WMS - never afterwards.

Check out www.k-store.co.uk for information on Keymas’ System to Manage your Warehouse