Interview questions about PLC SCADA DCS

These are topics from where most of the questions are asked if you apply for PLC SCADA DCS jobs.

If you are a fresher then Normal PLC questions you would be asked:

  1. Like which are the family of PLC’s you have worked on or you know about. Most of the industries use Rockwell and siemens PLC’s
  2. What kind of PLC programs you can work on - like ladder or structural text or functional blocks (FB’s)

If you are a bit experienced these questions will be asked:

  1. Recent projects where you have configured PLC’s
  2. How did you set up the communication? which communication interface did you use?
  3. PLC to PLC communication basics
  4. PLC to server communication basics
  5. Data concentrators logic
  6. Interviewer may ask you to write a small logic program for a scenario

Mostly PLC communication is one topic where you would be asked more questions as that is one challenging area

SCADA questions mostly will be

  1. which scada you had worked on
  2. What kind of Scada, bottling industry or automotive industry
  3. Which PLC you have communicated for designing your SCADA
  4. PLC - SCADA communication setuP


  1. which DCS and for which industry did you setup DCS?
  2. What communication protocol did you use
  3. How you validated the data

Apart from that questions will be on:

  1. communication protocols
  2. TCP/IP communication
  3. Ethernet IP (this one is rockwells)
  4. Profinet (siemens)
  5. Profibus
  6. Modbus communication