Operations · MES

Manufacturing execution (MES)

The record of what actually happened on the line, minute by minute.

Vendors Siemens Opcenter, Rockwell FactoryTalk, AVEVA, SAP ME / DMC, in-house

01 What it holds

The data inside it

In one sentence

Production confirmations, downtime events, speed loss, quality results and batch genealogy — the only place the difference between planned and actual production exists.

meskey records
Work order, Operation, Asset / Work centre, Downtime event, Reason code, Batch / Lot, Quality result, Material consumption

02 Getting the data out

Extraction, and the keys that decide whether it joins

Extraction

Usually a plant historian or database per site, extracted per site rather than centrally. Site-by-site schema variation is the norm even under one vendor.

Join keys

Work order links to ERP but often with a site prefix or a local numbering scheme. Asset identifiers rarely match the ERP equipment master or the CMMS.

03 What goes wrong

The failures that look like success

Each of these produces a number that is plausible, reconciles to something, and is wrong. They are worth reading before the first extract, not after the first dispute.

Gotcha 01

Reason codes differ per plant

Downtime taxonomy is configured locally, so group-level loss analysis needs a mapping layer that somebody has to own.

Gotcha 02

Time is local and shifts cross midnight

Shift definitions, daylight saving and site time zones make naive time-based aggregation wrong in a way that is very hard to spot.

Gotcha 03

Confirmed quantity is not produced quantity

ERP confirmation and MES output are recorded at different moments and often at different granularity. The reconciliation rule has to be defined, not discovered.

Gotcha 04

High volume, low value per row

Second-level data is enormous. Aggregating too early loses the ability to explain a loss; aggregating too late costs a fortune to store.

04 Joins that matter

What this system is worth joining to

Join toWhat it lets you answer
ERPto value output and losses at standard cost
CMMSto connect downtime to maintenance history and spares
QMSto trace a complaint back to the batch and shift that made it

06 Questions

Frequently asked

Why do MES and ERP never agree?

They are answering different questions at different times. MES records physical events as they happen; ERP records financial confirmations when they are posted. Both are right, and the reconciliation has to be a governed rule.

What is the first join worth making?

MES output and scrap to ERP standard cost. It turns a percentage into a margin line and is usually the fastest way to make a factory conversation financial.

Connect this system without replacing it

SCIKIQ reads it in place, resolves the entities inside it and governs what the fields mean.

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