Distributed SCADA architecture in SCADA systems - Step-by-Step Execution

Process Flow - Distributed SCADA architecture

Field Devices

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Remote Terminal Units (RTUs)

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Communication Network

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SCADA Master Stations

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Central Control System

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Operator Interface

Data flows from field devices through RTUs over a network to master stations, then to central control and operator interfaces.

Execution Sample

SCADA systems

Field Devices -> RTUs -> Network -> Master Stations -> Central Control -> Operator Interface

Shows the data path in a distributed SCADA system from sensors to operator.

Process Table

Step	Component	Action	Data Flow	Result
1	Field Devices	Collect sensor data	Data generated	Raw data ready
2	RTUs	Receive data from field devices	Data received	Data formatted and buffered
3	Communication Network	Transmit data	Data sent over network	Data arrives at master stations
4	SCADA Master Stations	Process and analyze data	Data processed	Control commands generated
5	Central Control System	Aggregate data from masters	Data aggregated	System-wide view created
6	Operator Interface	Display data and controls	Data displayed	Operator monitors and controls
7	End	No more data to process	N/A	System waits for new data

💡 System waits for new data after completing one full data cycle

Status Tracker

Component	Initial State	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	Final State
Field Devices	Idle	Data generated	Data sent	N/A	N/A	N/A	Idle
RTUs	Idle	Idle	Data received	Data forwarded	N/A	N/A	Idle
Communication Network	Idle	Idle	Idle	Data transmitted	N/A	N/A	Idle
SCADA Master Stations	Idle	Idle	Idle	Idle	Data processed	Commands sent	Idle
Central Control System	Idle	Idle	Idle	Idle	Idle	Data aggregated	Idle
Operator Interface	Idle	Idle	Idle	Idle	Idle	Idle	Data displayed

Key Moments - 3 Insights

Why does data pass through RTUs before reaching master stations?

RTUs collect and format data from field devices, acting as local gateways before sending data over the network to master stations, as shown in steps 1 and 2 of the execution_table.

What happens if the communication network fails?

Data cannot reach master stations, stopping the flow at step 3. The system waits for new data, as noted in the exit_note.

How does the operator interface get updated data?

Data flows through central control after master stations process it, then to the operator interface for display, as seen in steps 5 and 6.

Visual Quiz - 3 Questions

Look at the execution_table, at which step does the SCADA Master Station process data?

A Step 3

B Step 4

C Step 5

D Step 6

💡 Hint

Check the 'Component' and 'Action' columns in execution_table row for step 4.

According to variable_tracker, what is the state of RTUs after step 3?

A Data forwarded

B Data received

C Idle

D Data generated

💡 Hint

Look at the RTUs row under 'After Step 3' in variable_tracker.

If the communication network is down, which step in execution_table will fail?

A Step 2

B Step 4

C Step 3

D Step 5

💡 Hint

Step 3 involves data transmission over the network.

Concept Snapshot

Distributed SCADA architecture moves data from field devices through RTUs and a communication network to master stations, then to central control and operator interfaces.
Each component processes or forwards data.
Network reliability is critical.
Operators monitor system-wide data via interfaces.
This setup improves scalability and fault tolerance.

Full Transcript

Distributed SCADA architecture involves several components working together to collect, transmit, process, and display data. Field devices collect raw data, which RTUs receive and format. This data travels over a communication network to SCADA master stations that analyze and generate control commands. The central control system aggregates data from multiple master stations to provide a comprehensive system view. Finally, the operator interface displays this data and controls for human monitoring and intervention. The execution table shows each step's action and result, while the variable tracker follows the state of each component through the process. Key moments clarify why RTUs are needed, the impact of network failure, and how operators receive updated data. The visual quiz tests understanding of these steps and states. This architecture ensures efficient, scalable, and reliable control of industrial processes.