Industrial PLC Automation Interview Questions 2019

  INDUSTRIAL AUTOMATION 

INSTRUMENTATION QUESTIONS

GENERAL TERMINALOGY-

      Sensor - Sensor is a device that converts a physical property such as temperature, pressure, relative humidity, flow etc. into an electrically or mechanically recognizable, measurable signal.

     Transducer - A transducer  is a device that converts one form of energy to another form of energy such as pneumatic to electric or vice versa.

      Transmitter - Output from a sensor or a transducer may not be strong enough to be transmitted over long distances. Transmitter is a device used to amplify the signal.

      Controller - It is a device that compares the signal from a Sensor, Transducer or Transmitter with the desired value and generates a signal based on error.

      Controlled Device - It receives signal from controller and varies the flow of control agent like water, air. It may be a damper or a control valve connected to an actuator.

      Stat - Combination of sensor and controller functioning in one device is often called a ‘stat’ like thermostat, humidistat, etc.

      Process & Controlled Variable – Say for example, in an air-conditioning system, parameter being controlled such as temperature, RH, pressure etc. is controlledvariable and the changes in these parameters are due to influencing factors in process.

      Control Medium – It is the air, steam or water the flow regulation of which influences the process to get the desired value of controlled variable.

      MEMORY

      Read Only Memory (ROM) - Usually refers to a type of semiconductor memory often used for permanent storage of data or programs that do not change.

      Random Access Memory -Usually refers to a type of semiconductor memory often used for temporary storage because it requires the continual application of power to retain information. For some systems, battery backup is used to prevent data or program loss in the event of a power outage.

      Erasable Programmable Read Only Memory -A type of semiconductor memory often used for storage of data or programs that change infrequently. EPROM chips must be removed from the circuit to be erased and reprogrammed. EPROMS retain their contents when power is lost.

      Baud Rate- A way of describing the amount of data that can be sent on a signal line. Often used synonymously with bits per second; however, baud rate was originally intended for use in telegraphy application to refer to signal events per second.

      Byte  -Eight consecutive bits

      Binary Number- A number made up only of 1's and 0's that represent powers of two (2). Digital equipment uses binary numbers to represent numerical values or the on or off condition of devices.