IIoT integration with SCADA in SCADA systems - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding IIoT Data Flow in SCADA Systems

Which component in an IIoT integrated SCADA system is primarily responsible for collecting real-time data from field devices?

A Data analytics platform

B Historian server

C Human-Machine Interface (HMI)

D Remote Terminal Unit (RTU)

💡 Hint

Think about the device that directly communicates with sensors and actuators in the field.

The Remote Terminal Unit (RTU) collects real-time data from field devices and sends it to the SCADA system for monitoring and control.

💻 Command Output

intermediate

Output of MQTT Broker Status Command

What is the expected output of the following command on a Linux server running Mosquitto MQTT broker?

systemctl status mosquitto

A Active: active (running) since [timestamp]

B Failed to start mosquitto.service: Unit not found.

C Active: inactive (dead) since [timestamp]

D Syntax error: unknown command 'status'

💡 Hint

Check if the service is running properly.

The command shows the current status of the Mosquitto MQTT broker service. 'Active: active (running)' means it is running correctly.

❓ Configuration

advanced

Correct MQTT Broker Configuration for SCADA Integration

Which MQTT broker configuration snippet correctly enables persistent message storage and allows anonymous client connections for SCADA IIoT integration?

A

persistence true
persistence_location /var/lib/mosquitto/
allow_anonymous true

B

persistence false
persistence_location /tmp/
allow_anonymous false

C

persistence true
persistence_location /etc/mosquitto/
allow_anonymous false

D

persistence false
persistence_location /var/lib/mosquitto/
allow_anonymous true

💡 Hint

Persistent storage keeps messages saved across restarts. Anonymous access allows clients without credentials.

Setting 'persistence true' with a valid storage path and 'allow_anonymous true' enables message durability and client connection without authentication, suitable for some SCADA IIoT setups.

❓ Troubleshoot

advanced

Diagnosing SCADA MQTT Connection Failure

A SCADA system fails to receive data from IIoT devices via MQTT. Which of the following is the most likely cause if the MQTT broker logs show 'Connection refused: not authorized'?

A The MQTT broker is not running.

B The client is using incorrect credentials or lacks permission.

C Network cable is unplugged on the SCADA server.

D The MQTT topic name is misspelled in the SCADA configuration.

💡 Hint

Focus on the authorization error message in the logs.

'Connection refused: not authorized' means the client tried to connect without proper credentials or permissions, causing the broker to reject the connection.

🔀 Workflow

expert

Correct Order of Steps for IIoT Data Integration into SCADA

Arrange the following steps in the correct order to integrate IIoT sensor data into a SCADA system using MQTT:

A 1,3,2,4

B 2,3,1,4

C 1,2,3,4

D 2,1,3,4

💡 Hint

Think about preparing the broker before connecting devices and subscribing.

First, configure the MQTT broker to handle topics and permissions. Then deploy sensors as MQTT clients. Next, configure SCADA to subscribe to topics. Finally, verify data flow.