The model
The ISA-95 standard, adopted as the IEC 62264 series, describes the integration between enterprise management and production control. It distinguishes several levels, from the physical process to enterprise planning.
Level 4 — business
- ERP: orders, inventory, costs
Level 3 — operations
- MES: execution, detailed scheduling
Levels 0 to 2 — shop floor
- Process, sensors, controllers, supervision
What each level does
- Level 4 — business: orders, purchasing, inventory, costs, planning. This is ERP territory.
- Level 3 — manufacturing operations: detailed scheduling, execution tracking, in-process quality. This is MES territory.
- Levels 0 to 2 — process, sensors, controllers and supervision.
Why it is useful
The model avoids asking the ERP for what belongs to the MES, and vice versa. It forces you to define the exchanges between levels: orders going down, reports and consumption going up.
Limits
In an SME, the ERP often covers part of level 3 with work orders and entries at the work center. The exact boundary is decided on your shop floor, not in the standard.