Interview Questions on Automation Part-1

Introduction

This is our second post regarding the most asked interview question answers for instrumentation and control or industrial automation. In this post, you can find Interview Questions on Automation Part-1.

1. Difference between PLC and DCS?

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Check out the whole post on this topic https://worldofinstrumentation.com/what-is-a-difference-between-plc-scada-and-dcs/

2. What is the difference between SCADA and DCS?

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Ans: -See my post on the Difference Between PLC, SCADA, and DCS?

3. Full for SCADA and DCS?

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• Supervisory Control and Data Acquisition
• Distributed Control System

4. What is VFD?

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Its variable frequency drives. To know more information, see our dedicated post about VFD

5. Different types of PLC programming language?

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• Instruction List (IL)
• Structured Text (ST)
• Ladder Logic (LD)
• Sequential Function Charts (SFC)
• Function Block Diagram (FBD)

6. What is the full form of PLC?

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Programmable Logic Controller (PLC)

7. What is an SIS system?

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SIS is Safety Instrument System and is an additional protection layer created for plant safety.

To learn more about SIS I recommended Exida Website, on this website you can find all the resources related to Functional Safety.

8. Must condition for cascade control strategy?

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Must condition for Cascade control is inner loop is faster than the outer loop

9. What derivative control is not used alone?

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The derivative controller is not used alone because when a sudden change in input signal leads to a large steady-state error makes the process unstable.

And the Derivative controller amplifies noise in the system. The rate of change of error is zero then the output of the controller becomes zero.

10. What is used in critical loops of plant DCS or PLC?

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For critical loops like Fire Alarms plc is preferred because the

The response time of PLC is faster than DCS.

11. Which type of controller is used for temperature control?

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PID controller used for temperature controller.

12. What is VFD and tell something about it?

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Full form of VFD (Variable Frequency Drive). It is used for precise speed control of any AC Motor. VFD helps to improve power saving for any industry.

13. What is HMI?

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HMI stands for Human Machine Interface. HMI is a software application that offers interaction and communication between operator and machine or production. It is translating complex data into accessible information.

14. How does VFD work? or is the Working principle of VFD?

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If you want to know about how VFD works then check out my post on VFD working principles and VFD provider companies in the world.

15. Full form of SIS?

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Safety Instrument System

Note: –

Before appearing for an interview to go through your projects you must thoroughly know your project details.

Remember what you have mentioned in your resume like

• 1)area of interest
• 2)skills

and consider it in your preparation.