This is the second of the series and we are going straight to the heart of WITNESS, the main element. In a game of Chess this would be the Queen, the Machine (in the original Witness) or Activity (in business process version). Unlike many of the simulation products often labelled as ‘Simulators’, WITNESS doesn’t have a large selection of different elements to represent work locations or process steps. The WITNESS machine is a ‘super’ element; it is a combination of ‘operation’ and ‘location or resource’. 

The Machine has great flexibility allowing it to be easily configured through a series of options selectable from droplists etc in a remarkably simple ‘form’ such that WITNESS only needs the one Machine. The flexibility offered includes the number of steps/sub-cycles, numbers of entities entering and leaving at each sub-cycle, ability to combine or split entities and use of additional resources.

This means the single element can represent a plethora of real-world objects, machine tools, desks, ovens, robots, palletisers, lorries, loading bays etc. Not surprisingly the machine also has the features to support multiple changeovers and breakdowns.

Added to the droplist options that the modeller has at their disposal they can also add control logic at all the key points, i.e. events or state changes that occur in the machine however it is configured. We have always felt this super flexible element is always much more powerful for a modeller than either a long list of pre-configured elements or more conceptual approaches offering a pure code interface or diagramming facility.

Given the machine is a ‘resource’ it can be controlled by shift patterns and very importantly it has a ‘quantity’ which manages multiple instances of a machine. This quantity can be varied by data during a simulation experiment to model the investment in new equipment at particular dates or simulate the disposal of assets. The real power and flexibility comes from the fact that 99% of the information that used to configure a machine can be different for each instance of a machine.  The machine element is a huge part of the power and flexibility of WITNESS; it is loved by the users and provides the answer to many modelling situations faced across a wide selection of industries and applications. One could say the machine is the ‘super hero’ of WITNESS.