System Architecture and Configuration
What the exam tests
This domain covers MES deployment structure: ISA-95 equipment hierarchy, servers and high availability, network segmentation, master data, configuration versions, environments, and workflow design.
Core rules
- The ISA-95 equipment hierarchy commonly runs enterprise, site, area, work center, work unit, and equipment. Consistent hierarchy supports reporting and authorization.
- Production configuration includes product definitions, routings, BOMs, work-center capabilities, reason codes, and workflow rules. Changes need versioning and effective dates.
- A DMZ separates plant-floor networks from enterprise networks. Flat, unrestricted connectivity is an architectural red flag.
- High availability reduces single points of failure; it does not replace backup, restore testing, or disaster recovery.
- Configuration should move through development, test, and production environments with controlled promotion.
Worked example
A new product requires a revised routing and a new BOM effective 1 March. If the routing is edited in place, February work orders may pick up March logic. The correct approach is to create a new version with an effective date, test it in a non-production environment, and validate that released orders retain their intended version. Reasoning: effective dating preserves historical execution and auditability.
Traps
- Hard-coding site names, equipment IDs, or reason codes into custom code.
- Testing configuration changes directly in production.
- Treating backups as disaster recovery without restore tests.
- Ignoring time synchronization and certificate management in architecture design.