In digital production environments, several systems capture and visualize process data. Manufacturing Execution Systems (MES) and Supervisory Control and Data Acquisition (SCADA) are often confused because both work with real-time information.
The distinction lies in scope, purpose, and data context:
SCADA monitors and controls machine-level processes.
MES analyzes, records, and optimizes production at plant level.
Both systems are essential parts of the manufacturing IT stack. Their interaction ensures seamless information flow from sensor to management.
| Level | System Type | Main Function |
|---|---|---|
| Level 4 | ERP | Business planning and logistics |
| Level 3 | MES | Production execution and performance analysis |
| Level 2 | SCADA / Control | Process supervision and control |
| Level 1 | PLC / Controller | Machine-level automation |
| Level 0 | Sensors / Actuators | Physical data acquisition |
SCADA operates close to the automation layer; MES manages the operational management layer above it.
| Criterion | MES | SCADA |
|---|---|---|
| ISA-95 Level | 3 | 2 |
| Primary Function | Production execution, KPI analysis, traceability | Real-time visualization, control, alarm handling |
| Data Domain | Aggregated operational and machine data (BDE/MDE) | Raw sensor and process data |
| Time Scale | Minutes – hours | Milliseconds – seconds |
| Users | Production managers, quality, supervisors | Operators, maintenance, control room staff |
| Key KPIs | OEE, scrap, shift output, downtime | Pressure, temperature, flow, valve status |
| Objective | Efficiency and transparency | Process stability and safety |
In short: SCADA shows what happens; MES explains why it happens and what it means for performance.
Modern plants connect MES and SCADA through bidirectional interfaces:
Bottom-up (SCADA → MES)
Equipment states, alarms, cycle times
Process variables such as temperature or pressure
Production start/stop and downtime events
Top-down (MES → SCADA)
Work-order details and setpoints
Operator instructions and authorizations
Parameter adjustments for product or batch changeovers
This integration converts raw signals into contextualized production information.
Example: A SCADA alarm detects a pressure spike; MES links it to a specific order, product, and shift, enabling root-cause analysis and traceability.
Within a Smart Factory, SCADA acts as the data source, MES as the data interpreter:
SCADA captures events in real time.
MES standardizes and contextualizes them for business relevance.
ERP consumes aggregated MES information for costing and planning.
Together they enable vertical data integration, predictive analytics, and closed-loop optimization.
MES increasingly serves as a central data hub, enriching SCADA data with order, material, and quality context from ERP or PLM systems.
SYMESTIC Cloud MES connects directly to SCADA and PLC environments via OPC UA, MQTT, or REST APIs.
Key capabilities:
Real-time data acquisition without gateway delay
Automatic context mapping (order, product, operator, shift)
Central cloud data storage for cross-site analytics
Live KPI dashboards for OEE, scrap, and availability
Event-driven workflows: MES reacts instantly to SCADA triggers (e.g., limit exceeded → process hold)
In this setup, SCADA becomes the data provider, MES the decision layer — essential for digital excellence.
Integrated MES-SCADA environments deliver measurable value:
+20 % higher data accuracy via standardized interfaces
–60 % manual logging effort
Faster root-cause analysis for process deviations
Improved equipment uptime through early-warning mechanisms
Foundation for AI-based process optimization
The synergy lies in interaction: SCADA controls processes, MES interprets performance — together they enable real-time, data-driven manufacturing.
SCADA is the eyes of production.
MES is the brain.
SCADA ensures operational stability; MES provides insight, optimization, and traceability.
Only their integration forms the digital nervous system of the Smart Factory — transparent, efficient, and adaptive.
Summary:
SCADA monitors processes.
MES manages performance.
Together they create the backbone of intelligent manufacturing.