SACA IIoT and Industrial Networking 2

Question 1

What is the primary advantage of MQTT protocol over HTTP for IIoT device communications?

Accepted Answer

MQTT uses a lightweight publish-subscribe model with minimal overhead, ideal for constrained devices and unreliable networks

Answer

MQTT provides stronger encryption than HTTPS

Answer

MQTT is faster because it uses UDP instead of TCP

Answer

MQTT supports binary data natively while HTTP only handles text

Question 2

In industrial networking, what is the purpose of 'network segmentation' using VLANs or DMZs for OT systems?

Accepted Answer

To isolate OT control networks from IT business networks, limiting the spread of malware and unauthorized access

Answer

To increase network bandwidth by dedicating separate switches to each machine

Answer

To prioritize QoS traffic shaping for real-time PLC communication

Answer

To reduce cabling costs by sharing network infrastructure between OT and IT

Question 3

What does 'deterministic communication' mean in industrial Ethernet, and which standard achieves it?

Accepted Answer

Messages are guaranteed to be delivered within a bounded, predictable time window regardless of network load

Answer

All packets are encrypted and authenticated, ensuring only authorized devices can communicate

Answer

All connected devices receive every message broadcast, ensuring no data is missed

Answer

Network switches use token passing to control which device can transmit at any given time

Question 4

In Modbus RTU communications, what is the function of the 'CRC' (Cyclic Redundancy Check) appended to each message?

Accepted Answer

It allows the receiving device to detect transmission errors caused by electrical noise on the serial bus

Answer

It encrypts the message data to prevent unauthorized devices from reading register values

Answer

It provides the device address field that tells each slave which message is intended for it

Answer

It defines the function code indicating whether the message is a read or write operation

Question 5

What is a 'Fieldbus' and how does it differ from traditional 4-20mA point-to-point wiring?

Accepted Answer

Fieldbus carries digital communications for multiple devices on a single cable; 4-20mA dedicates one cable pair per device for one analog value

Answer

Fieldbus is a wireless protocol; 4-20mA is wired

Answer

Fieldbus requires intrinsic safety barriers; 4-20mA works without any safety interface

Answer

Fieldbus is only for sensors; 4-20mA supports both sensors and actuators

Question 6

What is 'OPC Unified Architecture' (OPC UA) and why is it significant for industrial data integration?

Accepted Answer

An open, platform-independent communication standard providing secure, structured data access between industrial devices and enterprise systems

Answer

A database schema standard for storing historical process data in SQL format

Answer

A wireless protocol specifically designed for battery-powered industrial sensors

Answer

A PLC programming standard that unifies IEC 61131-3 languages across vendors