What is SCADA in SCADA systems - Visual Explanation

Process Flow - What is SCADA

Sensors collect data

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Data sent to RTUs/PLCs

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RTUs/PLCs process data

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Data sent to SCADA Master Station

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SCADA software displays data

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Operator monitors and controls

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Commands sent back to RTUs/PLCs

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Field devices act on commands

SCADA collects data from sensors, processes it, shows it to operators, who then control devices remotely.

Execution Sample

SCADA systems

Sensor -> RTU/PLC -> SCADA Master -> Operator -> Command -> RTU/PLC -> Device

Shows the flow of data and commands in a SCADA system from sensors to operator and back.

Process Table

Step	Action	Source	Destination	Result
1	Collect data	Sensor	RTU/PLC	Data captured from field device
2	Send data	RTU/PLC	SCADA Master Station	Data transmitted for processing
3	Display data	SCADA Master Station	Operator	Operator sees real-time info
4	Operator decision	Operator	SCADA Master Station	Control command created
5	Send command	SCADA Master Station	RTU/PLC	Command sent to field device
6	Execute command	RTU/PLC	Field Device	Device changes state as commanded
7	Loop back	Field Device	Sensor	New data collected reflecting change

💡 Cycle repeats continuously to monitor and control the system

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	Final
Data	None	Raw sensor data	Processed data at SCADA	Displayed data	Command created	Command sent	Device state changed	New sensor data

Key Moments - 3 Insights

Why does data flow back to the sensor after command execution?

Because the system continuously monitors changes, new sensor data reflects the device's updated state, as shown in execution_table step 7.

Who controls the devices in a SCADA system?

The operator controls devices remotely via commands sent through the SCADA Master Station, as seen in steps 4 and 5.

What role do RTUs/PLCs play?

RTUs/PLCs act as middlemen that collect data from sensors and execute commands on devices, bridging field devices and the SCADA Master Station (steps 1, 2, 5, 6).

Visual Quiz - 3 Questions

Look at the execution_table, at which step does the operator see the real-time data?

A Step 3

B Step 1

C Step 5

D Step 7

💡 Hint

Check the 'Display data' action in execution_table step 3.

At which step is a control command sent to the RTU/PLC?

A Step 2

B Step 4

C Step 5

D Step 6

💡 Hint

Look for 'Send command' action in execution_table.

If the operator does not send any command, which step will not occur?

A Step 3

B Step 6

C Step 4

D Step 1

💡 Hint

Commands trigger device actions at step 6; without commands, devices don't change state.

Concept Snapshot

SCADA is a system that monitors and controls industrial devices.
Sensors collect data sent to RTUs/PLCs.
RTUs/PLCs forward data to SCADA Master Station.
Operators view data and send commands.
Commands go back to RTUs/PLCs to control devices.
This cycle repeats continuously.

Full Transcript

SCADA stands for Supervisory Control and Data Acquisition. It is a system used to monitor and control industrial processes. Sensors collect data from devices in the field. This data is sent to RTUs or PLCs, which process and forward it to the SCADA Master Station. The SCADA software displays this data to an operator. The operator can then send control commands back through the SCADA Master Station to the RTUs or PLCs. These commands cause devices to change their state. The system continuously loops, collecting new data to reflect changes. This allows remote monitoring and control of equipment.