MES software
A manufacturing execution system occupies the layer between process control and ERP: it turns a production order into executed, recorded work. Most MES disappointment comes from buying it to fix problems that live in the layers either side.
| Topic | Key point |
|---|---|
| The layer it occupies | Industrial systems stack roughly like this, and MES is defined by its neighbours more than by its features. |
| What genuinely varies between products | Discrete versus process orientation. |
| What an MES will not fix | An unreliable process. It records variation faithfully; it does not remove it. |
The layer it occupies
Industrial systems stack roughly like this, and MES is defined by its neighbours more than by its features.
| Layer | Question it answers | Typical system |
|---|---|---|
| Control | What is the valve doing right now? | PLC, DCS |
| Supervisory | What is the line doing, and can I intervene? | SCADA, HMI |
| Execution | Which order is running, on what, with what material, by whom, and was it right? | MES |
| Planning | What should we make, from what stock, for which customer? | ERP |
An MES turns a planning instruction into executed, recorded production. Its characteristic outputs are genealogy and traceability, real production performance against plan, and an electronic record of how each batch or unit was actually made.
What genuinely varies between products
- Discrete versus process orientation. Serial-number genealogy and batch genealogy are different data models. Products built for one are usually awkward at the other.
- Regulated-industry depth. Electronic batch records, review by exception and e-signature workflows are heavy features that only some products carry.
- How much it assumes about connectivity. Some expect a clean historian and well-named tags; some bring their own acquisition layer.
- Configuration versus development. Whether a line change is a configuration task or a project decides your long-run cost more than the licence.
- ERP coupling. Pre-built connectors to your specific ERP, or an integration project.
What an MES will not fix
- An unreliable process. It records variation faithfully; it does not remove it.
- Bad master data. Wrong routings and bills of material produce precise records of the wrong thing.
- Planning problems. If the schedule is wrong, executing it accurately does not help.
- Missing instrumentation. An MES reports what it is fed.
The recurring pattern is buying an MES to fix a problem that lives one layer up or one layer down. Establish which layer your actual complaint belongs to before shortlisting.
Frequently asked questions
What does MES software do?
It sits between supervisory control and ERP, turning a production order into executed and recorded work. Its characteristic outputs are traceability and genealogy, production performance against plan, and an electronic record of how each batch or unit was actually made.
What is the difference between MES and SCADA?
SCADA answers what the equipment is doing now and lets an operator intervene. MES answers which order is running, on what equipment, with which material and by whom, and whether the result conformed. SCADA is equipment-centric; MES is order-centric.
Do we need MES if we already have ERP?
ERP plans and settles; it rarely knows what happened on the line in the detail traceability requires. If you need genealogy, batch records or real performance against plan, that gap is what MES fills. If you only need to know that an order completed, you may not need one.
Why do MES projects overrun?
Usually master data and process definition. Routings, bills of material and work instructions have to be correct and complete before the system can execute against them, and that cleanup is frequently discovered rather than planned.
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Software that helps
Proficy
MES, historian and digital-twin tooling for manufacturing; divested by GE Vernova in 2026.
AVEVA Predictive Analytics
Early-warning analytics for critical process and power assets.
Siemens Insights Hub
Industrial IoT-as-a-service for analytics and digital twins (formerly MindSphere).