Today we look at the second approach towards MES migration, the Phased Introduction method. Again as the name suggests, the approach entails phase by phase introduction of the new application, while gradually switching off the old one. There are mainly two ways in which a Phased Introduction might take place. First would be the introduction of the new application area by area, step by step and equipment by equipment, the other would be the introduction of new functionality one function at a time or more depending on requirements and the state of the particular process in question.
Why go with a phase by phase introduction instead of say a big bang migration? Phased Introduction would be ideal for organizations where the level of integration the old MES application has with other enterprise applications is higher and where the risks associated with downtime are also high. For such organizations, the time required to make the switch is no longer the top priority, rather it’s the mitigation of risks and comparatively affordable cost that matters. What is also important is the fact that master data is retained and transferred properly to the new application, without disrupting the operation.
Phased approach implies that at a given time during migration, both the old MES and the new MES would be playing an active part in the execution of the process; however their roles in the operation would be different. As the migration process moves forward, the old MES loses ground to the new one, until at one time the new MES is fully responsible for the operation.
The first variant of the phased approach is the Phased Introduction by Manufacturing Unit approach, where the new MES is introduced area wise. Here generally the introduction of the new MES would be right at the point where the process begins, but this again is not mandatory. The new MES would replace the old MES one area at a time, and in that particular area the new MES covers all its execution steps and equipment. The Master Data resides in both systems, and generally an interface between them allows routing of material from one system to the other. There is a routing layer which is equipped with the logic to understand which system to place a particular command requisition and also to pass data between the two systems. In terms of functionality the new MES application needs to have at least the functionality corresponding to the old system, in order to maintain the seamlessness of the operation and to avoid any UX related issues.
Another key point to mention here is that in complex and layered processes with multiple loops, it is important to carefully maneuver the data between the two MES systems, as the ideal flow of information between the two applications is unidirectional rather than looped. Instances where loops can be avoided should be preferred, as it helps to maintain data integrity and avoid the hassle of creating a complex routing protocol between the two systems.
As the users get acquainted with the new system’s functionality the next phase of introduction is implemented, and so on until all areas of the process are governed by the new application.
Phased Introduction approach executed by Functionality, where the new MES replaces the old application one function at a time. It sounds lucrative in theory - imagine that only an SPC of the new MES is required and the users can access it while using their old system with which they are more comfortable.
But, before getting too happy, ...
... read more and the complete blog on MES migration here