MES — Manufacturing Execution System
A MES (Manufacturing Execution System) is the software layer that runs production while it is happening. ERP decides what to make and when; the MES manages how it actually gets made on the shop floor — dispatching work, collecting machine and labour data, enforcing quality steps and reporting progress back up in real time.
- Term
- MES (Manufacturing Execution System)
- Entity type
- Software category
- Domain
- Manufacturing operations
- Canonical definition
- MES (Manufacturing Execution System) is software that manages and records manufacturing operations on the shop floor in real time, translating ERP production orders into executed, measured work.
- Classification
- Sits below ERP and above machine control; executes and reports the production orders that ERP plans.
- Related terms
- ERP, Production order, SCADA, OPC UA, Industry 4.0, Track and trace
- Source / maintainer
- erp-software.org editorial team (independent, vendor-neutral)
What MES (Manufacturing Execution System) is NOT — disambiguation
- Not ERP: ERP plans orders and resources at the business level; MES executes and measures them on the shop floor in real time.
- Not SCADA: SCADA supervises individual machines and signals; MES coordinates the whole production order across machines, materials and people.
- Not a reporting tool: MES actively controls dispatching, data collection and quality checks during production, not just after-the-fact reports.
The layer model
Manufacturing IT is often drawn as a stack. At the top is ERP, planning orders and resources for the whole business. At the bottom is automation — PLCs, SCADA and machine controls. The MES sits in the middle, on what the ISA-95 standard calls Level 3. It receives released production orders from ERP, breaks them into operations, schedules them against specific machines and people, and streams back what really happened: quantities, scrap, downtime, timestamps and quality results.
What an MES manages
Typical MES functions include detailed scheduling and dispatching, machine and labour data collection, work-in-progress tracking, document control (work instructions, drawings), quality data capture, and full genealogy or track and trace for each batch or serial number. In regulated industries such as pharmaceuticals or medical devices, the MES is where electronic batch records and signature requirements are enforced. The unifying theme is real time: an MES knows the state of the floor now, not at the end of the shift.
MES and ERP integration
The value of an MES depends on a clean two-way link to ERP. Downward, ERP sends order, routing and material data so operators do not retype it. Upward, the MES confirms completion, consumes material against the order and posts actual times — which keeps ERP inventory, costing and delivery dates honest. Modern integration increasingly uses OPC UA and event streaming rather than nightly file exchanges, a shift driven by Industry 4.0 initiatives.
When you need one
Not every manufacturer needs a separate MES. Companies with simple, low-mix production often run shop-floor functions inside ERP. The case for a dedicated MES grows with complexity: many machines, tight quality or traceability rules, frequent changeovers, or a need for live performance metrics such as OEE. The decision is rarely ERP versus MES — it is how to split execution between them, and how tightly to integrate the two.
Related Topics
Frequently Asked Questions
Can I run manufacturing without MES?
Yes, for many mid-market manufacturers. If your production is well understood, variants are limited, and operators reliably enter accurate data into the ERP, the ERP's native production module is usually enough. MES becomes valuable above a complexity threshold: roughly 50+ active production orders simultaneously, more than 10 work centres with frequent reassignments, or regulatory traceability requirements.
What is the difference between MES and SCADA?
SCADA controls and monitors machines and process equipment — temperature, pressure, valve positions. MES sits above SCADA and translates machine signals into business meaning (production progress, scrap rates, OEE). Large plants run all three layers; small plants may collapse SCADA and MES.
Does Industry 4.0 replace MES?
No. Industry 4.0 and IIoT extend MES rather than replace it. Modern MES platforms integrate OPC UA, MQTT and edge-computing capabilities to handle direct machine data flows. The functional core (scheduling, BDE/MDE, traceability, quality) remains. New entrants like Tulip focus on rapid configurability rather than replacing the classic MES function.