Blogger Tips and TricksLatest Tips And TricksBlogger Tricks

Friday, 20 May 2016

PLC SCADA DCS Interview Questions and Answers 1


 PLC SCADA DCS Interview Questions and Answers 1

PLC Interview Questions and Answers


SCADA Interview Questions and Answers



DCS Interview Questions and Answers

Friends this the most awaited post I am writing for all the freasher in the field of Automation and those are looking for job and preparing for interviews. It is difficult to find the PLC interview questions and answers If you like the post Please like our FB page ,Do comment, and Share.
So here we go.
Question : What is a PLC?
Answer: Programmable Logic Controllers are industrially hardened micro computers, designed to replac e electromechanical relays, used to control machines and processes.
Question : What are the main advantages of PLC?
Answer:
1.      Modular design
2.      Increased reliability  
3.      Lower cost
4.      Compact size
5.      Ease of programming
6.      Rugged construction and designed to withstand vibrations, temperature, humidity and noise
7.      Ability to communicate with computer
Question : What are the major areas of application of PLC?
Answer:
1.       Sequence control, timing, counting, and data calculation
2.       Batch or continuous process control
3.       Precise position/motion control
4.       Open loop or feedback control, process data acquisition and display

Question :  What are the advantages of PLC over Relays?
Answer:
1.       They have to be hard-wired to perform a specific function
2.       No hard-wire requirement
3.       When the system requirement change, the relay wiring has to be changed or modified
4.       Can be easily changed or expanded through program
5.       Higher power consumption
6.       Lower power consumption

Question :  Explain the classification of PLC.
Answer:
There are five major classification of PLC based on number of inputs and outputs, cost, functionality and physical size. They are
i.                 Nano : 16 I/O pins
ii.                Micro : 32 I/O pins
iii.              Nano or micro PLC could used on applications such as elevators, car washes or mixing machines.
iv.              Small : 128 I/O pins,2Kbytes memory, capable of simple to advanced level of machine control
v.                Medium: 2048 I/O pins, 32Kbytes memory, used for process control applications
vi.              Large: 8192 I/O pins, 750 Kbytes memory, mostly used to control individual production process or entire plants like paper and pulp, chemical and automotive and power plants.
 Question :  Explain the functions of PLC-input and output modules
Answer:
1. Input interface modules accept signals from the machine or process devices (120Vac) and convert them into signals (5Vdc) that can be used by the controller.
2. Output interface modules convert controller signals (5Vdc) in to external signals (120Vdc) used to control machine or process.
Question :  List out the programming languages in PLC.
Answer:
a. Ladder Logic Diagram
b. Sequential Function Charts
c. Instruction List
d. Function Block
e. Structured Text Diagram


Question: What is Ladder LogicDiagram?
Answer:
Ladder Logic Diagram is a symbolic language used in PLC. This diagram consist of series of symbols interconnected by lines to indicate the flow of current through the various devices. In ladder logic diagram the sides of the ladder forms the power sources and current flows through the various –logic input devices that form the rungs of the ladder.

Question: List the conditions for drawing thw ladder logic.

Answer:
a.      Contacts may be always inserted in the upper left.
b.      Coils must be inserted at the end of the rung.
c.      All contact must run horizontally.
d.      The number of contacts per network are limited
e.      Only one outout may be connected to a group of contacts
f.       Flow must be from left to right.
g.      The contact must be nested.
h.     Contact progression should be straight cross.
Question : Explain On-Delay and Off-Delay Timer instruction in PLC

Answer:
a)      The on delay timer operates such that when the rung containing the timer is true, the timer tiomed out period commences. At the end of the timer time out period an output is made active.
b)     The Off delay timer operation will keep the output energized for  time period after the rung cotaining the timer has gone false.
c)       
Question: What is PLC SCAN ?

Answer:
During each operating cycle the processor reads all the inputs , takes the values and energizes or de-energizes the output according to the user program. This process is known as PLC Scan . A single PLC scan consists of the I/O scan and the program scan.

ShareThis

Subscribe To Get FREE Tutorials! And More....

Labels

PLC Practice Problem PLC Ladder PLC Ladder Programming training & tutorials Free Training on PLC Ladder Programming training & tutorials PLC Timer SCADA Delta PLC PLC & Visual Basic Communication PLC Definition Introduction PLC Error PLC Error LED RSLinx Tutorial Types of Timers in PLC programmable Logic Controllers AB addressing ABB AC Drive AC Drive training cource Actuators Advantages and Disadvantages Addressing of Allen Bradley PLC Micrologix 1000 Addressing of Delta PLC DVP SS/ES/EX Addressing of Mitsubishi PLC FX2N Addressing of Modicon PLC Micro TSX 3722 Addressing of Siemens PLC S7 200 Advantages & Disadvantages of RTD Advantages & Disadvantages of all types Sensors Advantages of SCADA Allen Bradley PLC PWM (Pulse Width Modulation) error codes Allen Bradley SLC Controller Error Codes Ampere Voltage Ratings of circuit brakers Analog addressing Allen bradley Analog input in Allen Bradley PLC Applications of Sensors Basic PLC Ladder Programming Examples Capacitive Proximity Sensors blck diagram Capacitive proximity sensors Circuit brakers Circuit diagram of motor starter Communication Between two E1000 HMI and mitsubishi Fx2n PLC Communication between FX3U PLC and SCADA via RS485BD Configuring the DF1 Driver using RSLinx Configuring the Ethernet Driver Connection between 2 E-Terminals and FX2N PLC. DOL Motor Starter PLC logic DOP Series Human Machine Interface DVP14ss Delta HMI Delta HMI Program Download.Delta HMI Communication Cable Delta HMI and RS485 Communication Delta MMI Delta PLC Projects Delta PLC input output addressing Different types of Special motor Diffrence between PLC and DCS Ebook on Basics of Allen Bradley PLC pdf Ebook on Basics of Siemens PLC pdf Ebook on Basics of VFD PDF download Electrical maintenannce tips Electromagnetic relay Error Messages from RSLogix Emulate 500 Failsafe meaning Features of Delta HMI/MMI Following are the Free PLC Software's available from all leading brands such as Allen Bradley Free PLC Ebooks Free PLC SCADA TRAINNING & TUTORIAL Free PLC Training Full form of HART HART OSI reference model HART protocol structure HMI & ZIGBEE How Capacitive Proximity Sensors Works? How Inductive Proximity Sensor Works? How Ultrasonic Sensors Works? How to Select a Suitable Motor How to Select the Right VFD (Inverter) or AC Motor Drive Ladder Logic for AND Ladder Program for Automatic Door open close Ladder Programs for Gates List of Top Most Widely used PLC’s in the Industry List of Widley used PLC Companies. Low cost Wireless I/O’s using PLC Mitsubishi Mitsubishi PLC FX2N & HMI E1000 Networking using BDTP Technology Mitsubishi PLC input output addressing Modbus Communication Modbus Ethernet Modbus Serial Modbus.dll for Visual Basic Mormally open Contact Normally Close Contact Explained Motion Actuators Motor starter in control circuit NAND NO NC Explained NOR Gates with Truth Tables Nashik Nexgenie PLC Features Nexgenie PLC Port Nexgenie PLC input output OFF Delay Timer OLE for Process and Control ON Delay Timer OR Omron On line Ladder Program Editing for RSLogix 500 On line Ladder changes Online Editing Ladder Program Online Servo tuning PID Control Instruction PID PLC PID instruction in Allen Bradley PLC PLC & VB PLC Counter PLC Error Allen Bradley PLC Error messages in Allen Bradley PLC FBD PLC Fault PLC Industrial Automation Training Institute PLC Ladder Logic PLC ON Delay Timer PLC Run Led PLC SCADA Communication PLC SCADA DCS Training Centers PLC SCADA Driver PLC SCADA Training Chennai PLC and ZIGBEE PLC application PLC based Automated Guided Vehicle PLC based Final year Project PLC based Line follower robot PLC based Project Report PLC functional Block Diagram PLC input wiring PLC interview Question PLC interview questions PLC maiintence PLC power LED PLC program for star delta starter PLC retentive timer PLC training in Delhi PLC training in Mumbai PLC training in Pune PTO Allen Bradley PTO [Pulse Train Output] Instruction in Allen Bradley PLC Photoelectric Sensor Applications Photoelectric Sensor Applications in Automation industry Power cable Selection Proficy HMI/SCADA Cimplicity 8.1 Programming Languages for PLC Proximity sensor application Push to ON PUSH to OFF PLC program using NO NC and Coil Pwm RSLinx Tutorial | Configuring the DF1 Driver RSLinx Tutorial | Configuring the Ethernet Driver Scaling Analog Input using SCL Instruction in PLC [Scale Data] Schneider Schneider PLC addressing Selction of Servo Motor Selction of Stepper Motor Selection of AC Motor Selection of VFD Selection of stepper or Servo Motor Sensor applications Servo Motor Servo auto tuning Parameters Siemens Siemens input output addressing Signal Cables selection Simatic Wincc SCADA Single Push button to on and off motor Sinking and sourcing operations Softwares used in SCADA Solid State Relay construction Solid State Relay uses and Advantages Sourcing and Sinking Concept in PLC Standard Wiring Color Codes Stepper Motor Applications and Advantages Disadvantages Stepper application Stepper motor Selection Stepper motor and PLC Tag in SCADA Temperature sensors used with PLC Theory of Capacitive Proximity Sensors Theory of Ultrasonic Sensors Theory or Operation of Inductive Proximity Sensors Thermistor & Temp IC Sensors Thermocouple Trial Run of PLC Troubleshooting Allen Bradley PLC with RSLogix Emulate 500 Troubleshooting Tips for Electrical /Electronic Maintenance Tutorial on PLC Types of Actuators Types of Actuators used for Motion in Automation with Advantages & Disadvantages Types of Sensors Types of Timers in PLC | ON Delay Timer (TON) Typical circuit diagram of Star Delta starter Ultrasonic Sensor Applications Ultrasonic sensors Unitronics VB 6.0 and PLC VIsual Basic as SCADA What is HART What is SCADA (Supervisory Control And Data Acquisition) What is SMART Communication What is a PLC ? What is DCS? What is the difference between PLC and Microcontroller? XIO [Examine if Open] & XIC [Examine if Closed] Explained advantages & disadvantages of Servo Motors anlog input addressing DELTA PLC anlog input addressing Mitsubishi PLC anlog input addressing siemens automation training comparison of PLC and DCS connecting field devices to Programmable Logic Controllers contact reting of relay design of fail safe systems digital common ground connections distributed control system drawbacks of Servo Motor fail safe PLC Redundancy ladder logic Programming modbus examples noise in cables one input one output PLC program using NO NC logic opc overload relay operation photoelectric plc Response Time plc output wiring plc program for TV remote plc training programmable Logic Controllers List relay coil rating relay driving circuit relay isolation voltage selection of relay servo basics servo training star delta starter control wiring diagram types of Counter typical circuit diagram of Direct on line starter