MES architecture
ERP and MES: who owns what
The ERP runs the business; the MES runs production. A clear division of responsibilities avoids duplicated data, fragile integrations and spreadsheets in between.
Many manufacturers try to run production from the ERP. It is an understandable instinct — the ERP already has the items, the orders and the costs — and an expensive mistake.
Different questions, different models
The ERP answers business questions: what was sold, what must be bought, what it costs, what was invoiced. Its item records are administrative.
The MES answers production questions: how exactly is this product made, on which machine, with which tool, by whom, with which lot, how long did it take, what went wrong. Its records describe the process in detail.
Forcing one to do the other’s job produces either an ERP full of shop-floor workarounds or an MES duplicating the ledger.
A clean division
ERP → MES: production and sales orders, items, routings and bills of materials (as a starting point), purchase orders.
MES → ERP: progress and completions, actual consumption, scrap, quality results, actual times and costs.
The MES owns the detailed production model — routing steps, parameters, setups, reasons, controls — because it is the system that needs them every minute.
Integration that lasts
- exchange through structured, documented interfaces rather than direct table writes
- make errors visible and re-processable, not silent
- flag what has been exported so nothing is sent twice
- keep the ERP as the system of record for business data, and the MES for production facts
Done this way, each system does what it is good at — and nobody re-keys orders at the end of the shift.