A Manufacturing Execution System (MES) sits between the ERP system and the shop floor, providing real-time visibility into what is actually happening during production. While ERP plans what should be made and when, MES tracks what is being made right now — which jobs are running on which machines, where work-in-process inventory sits, and whether production is on schedule.
Core MES functions include work order dispatching, operator instructions, labor and machine time tracking, material consumption recording, in-process quality data collection, and production status reporting. In regulated industries, MES enforces process controls: verifying operator certifications, enforcing operation sequences, and capturing the electronic signatures that compliance requires.
The ISA-95 standard defines the functional boundary between ERP and MES, but in practice the lines blur. Modern manufacturing platforms increasingly combine MES, quality, and equipment monitoring capabilities into unified systems that eliminate the data silos and integration headaches of managing separate point solutions.