Explain how a Programmable Logic Controller (PLC) is different from an ordinary personal computer. Also write the advantages and disadvantages of PLC.

1 Answer

Answer :


PLC
PC
1 It has embedded processor with limited computing power
It has a CPU with high computing power 
2 Design of PLC is for reliable operation in industrial environment with nois
Design of PC is suitable for indoor or office use or mid range industrial environment
3 Start up time is negligible
Longer startup time
4 PLC has high reliability
PC is less reliable as comp to PLC
5 Software of PLC is mainly for real time 
Software of PC is designed for information processing
6 PLCs are available in compact sizes
Size of PLC is larger than PLC
7 Modularity is design of PLC makes it very
Addition of I/O module to PC is hardware dependent and

Advantages 

1) Flexibility. 

2) Implementing changes & correcting errors. 

3) Speed of operation. 

4) Reliability & maintainability. 

5) PLCS are smaller in size & can operate Number of devices at a time. 

6) Logic change can be very easily done by just adjusting the ladder logic. 

7) Operation of PLC can be displayed on CRT or LCD screen. 

8) Error occurred in operation can be very easily observed. 

9) PLC can keep records of status of Input & Output signals.

10) PLC can provide security for ladder programming. 


Drawbacks: 

1) PLC code is not portable. 

2) Cost of PLCs with analog I/O is very high as comp to digital i/o PLC 

3) Use of PLCs may be restricted in some high heat, vibration environment not suitable for electronic circuit

Related questions

Description : Explain with block diagram the working of programmable logic control system. (PLC).

Last Answer : Programmable logic controller:  Block diagram: OR Explanation: PLCs are industrially hardened microcomputers that perform discrete or continuous control functions in a variety ... provides an interface between the PLC and user during program development, start-up and trouble shooting

Description : Explain the role of watch dog timer in programmable logic controller.

Last Answer : Watch dog timer is a type of timer used to protect maloperation of PLC. It independently works( starts counting internal clock pulses) each time when PLC starts its execution. User program ... or some unknown condition, then watch dog timer overflows and generates nonmaskable interrupt to reset PLC.

Description : What forma programmable logic controller training is available in Oklahoma City?

Last Answer : Yes, there are formal classroom courses available in Oklahoma City about programmable logic controllers(PLC). You can enroll in Vatterott College which has an outstanding PLC program. They offer a ... Organization of PLC, and many other crucial areas of knowledge to complete your PLC training.

Description : List any two advantages and any two disadvantages of PLC.

Last Answer : Advantages of PLC: i) Increased productivity ii) Increased product quality iii) Increased flexibility and convertibility iv) Reduced manpower v) Reduced cost of product vi) Better inventory control vii) Increased ... v) PLCs are not very good at handling large amount of data, or complex data.

Description : List & explain the timer instruction of PLC. Draw the ladder diagram to verify (i) OR gate& (ii) NOR gate logic 

Last Answer : Depending on the time delay and operation, there are two types of timers  * PLC timer- (i) ON delay timer  (ii) OFF delay timer Description (i) ON delay timer 1) This instruction counts time interval when ... a) OR gate ladder diagram y = A + B b)NOR gate ladder diagram

Description : (i) List and explain the types of ROM.  (ii) List any four advantages of PLC.

Last Answer : ROM types  1) PROM  2) EPROM  3) EEPROM  1) PROM: - (Programmable Read Only Memory): In this memory it may be programed once and once only, by the user/programmer. The user than programs ... signals.  10) PLC can provide security for ladder programming.  11) Speed of PLC is in milliseconds.

Description : Interfacing devices for DMA controller, programmable interval timer are respectively…a) 8257, 8253 b) 8253, 8257 c) 8257,8251 d)8251,825721.

Last Answer : a) 8257, 8253

Description : The Intel 8259 is a - chip programmable interrupt controller  1. Single 2. Double 3. Triple 4. All of the above 

Last Answer : The Intel 8259 is a - chip programmable interrupt controller Single 

Description : State advantages of PLC.

Last Answer : 1) Flexibility. 2) Implementing changes & correcting errors. 3) Speed of operation. 4) Reliability & maintainability. 5) PLCS are smaller in size & can operate Number of devices at a time. 6) ... on CRT or LCD screen. 8) Error occurred in operation can be very easily observed and diagnosed.

Description : In CNC systems multiple microprocessors and programmable logic controllers work a.in parallel b.in series c.one after the other d.for 80% of the total machining time

Last Answer : a.in parallel

Description : Rules of FSM are encoded in. a. ROM b. Random logic c. Programmable logic array d. Allof these

Last Answer : d. Allof these

Description : Full form of PLA in CU: a. Progrmmable Logic Array b. Programs Load Array c. Programmable Logic Accumulator d. all of these

Last Answer : a. Progrmmable Logic Array

Description : What is field programmable logic array?

Last Answer : The second type of PLA is called a field programmable logic array. The user by means of certain recommended procedures can program the EPLA.

Description : What is programmable logic array? How it differs from ROM?

Last Answer : In some cases the number of don’t care conditions is excessive, it is more economical to use a second type of LSI component called a PLA. A PLA is similar to a ROM in concept; however it does not provide full decoding of the variables and does not generates all the min-terms as in the ROM.

Description : What is programmable logic array? How it differs from ROM?

Last Answer : In some cases the number of don’t care conditions is excessive, it is more economical to use a second type of LSI component called a PLA. A PLA is similar to a ROM in concept; however it does not provide full decoding of the variables and does not generates all the min-terms as in the ROM.

Description : List basic types of programmable logic devices.

Last Answer : 1. . Read only memory 2. . Programmable logic Array 3. . Programmable Array Logic

Description : Draw the block diagram of Programmable Logic Array.

Last Answer : block diagram of Programmable Logic Array

Description : Complex Programmable Logic Devices (CPLD)

Last Answer : Complex Programmable Logic Devices (CPLD) CPLDs are the collection of SPLD structures which are interconnected via multiplexer or switch matrix. CPLD consists of number of logic blocks or ... timing characteristics. CPLD are use in cost sensitive application and it have low power usage.

Description : Simple Programmable Logic Devices 

Last Answer : Simple Programmable Logic Devices (SPLD) There are three main types of SPLD architecture Programmable Logic Array (PLA), Programmable Array Logic (PAL) and Generic Array Logic (GAL). SPLD is made ... ). PAL can not be reconfigured. GAL uses EEPROM configuration so it can be reconfigured.

Description : What is programmable logic device?

Last Answer : Programmable Logic Devices (PLD) PLD chips can be erased electrically and program to implement different logic function. Designing with PLD chips is faster which  ... Logic (GAL). FPGA and CLPD are the types of advanced PLDs.

Description : Draw and explain the working principle of ultrasonic level measurement system. Also give advantages, disadvantages and applications of it.

Last Answer : Ultrasonic level detectors operate either by the absorption of acoustic energy as it travels from source to receiver or by the attenuation (frequency change) of a vibrating diaphragm face, oscillating at ... without making physical contact with the process material. 2. They have no moving parts.

Description : List and explain the different counters of PLC in detail.

Last Answer : A counter in PLC is an instruction equivalent to mechanical counter. A counter block of PLC has two control inputs, Count line and Reset line. When count line makes FALSE-to-TRUE transition, the counter ... down counter. The up-down counter has three inputs, count up, count down and reset.

Description : Draw and explain the block diagram of fuzzy logic controller.

Last Answer : Ans:  OR 1 Fuzzification: It is the action of transforming a given state as crisp input into fuzzy values by evaluating membership function for purpose to be used by a ... at producing a non- fuzzy control action that best represent the possibility of an inferred fuzzy control action

Description : Draw and explain Fuzzy logic controller. 

Last Answer : Explanation:-- Fuzzification: It is the action of transforming a given state as crisp input into fuzzy values by evaluating membership function for purpose to be used by a fuzzy ... a non- fuzzy control action that best represent the possibility of an inferred fuzzy control action

Description : Concerned about the impact on her firm's promotional messages, Karen Dickson of Magnum PLC., seeks an approach with immediate feedback. She is most likely to achieve this through. A)television advertising B)newspaper advertising C)publicity D)personal selling E)sales promotion

Last Answer : D)personal selling

Description : List advantages and applications of PLC.

Last Answer : The advantages of PLC are as follows: 1. Flexible in Nature: One model of PLC can be used for different operations as per requirement. 2. Easy to install and troubleshooting: In hard ... 1.Continuous bottle filling system 2.Batch mixing system 3.stage air conditioning system 4.Traffic control 

Description : Which one of the magnetic storage disk is also known as diskette? Explain it with its advantages and disadvantages. -Technology

Last Answer : Floppy disk drive is also known as diskette or FDD. It is a computer disk drive that enables a user to save data on removable diskettes.This portable storage device is a rewritable media that can ... damaged and not much reliable.2. Quite slow to access and retrieve data.3. Easily affected by heat

Description : Explain the Mendeleev’s Law of classification of elements also describe advantages & disadvantages of his periodic table.

Last Answer : Ans : Mendeleeve's Law of Classification : Mendeleeve in 1869 arrange elements in order of increasing atomic masses. He placed chemically similar elements vertically beneath each other & concluded that : The ... metals. No Idea Of Atomic Structure : It failed to give the idea of atomic structure.

Description : Describe the resistive method for liquid level measurement. Write its advantages and disadvantages.

Last Answer : Working: This method uses mercury as a conductor as shown in the figure. A number of contact rods are placed at various liquid levels. As the level of liquid rises in the tank, head h ... connected in series is calibrated in terms of the liquid level and indicates the liquid level directly. 

Description : Write any four advantages and four disadvantages of thermal power plant.

Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Description : Write advantages and disadvantages of positive and negative feedback.

Last Answer : Advantages of Positive Feedback: i) Voltage gain increases. ii) No phase shift is provided. iii) Feedback signal and input signal are in phase. iv) Input and Output voltage increases.  ... ii) Feedback signal and input signal are out of phase. iii) Input and Output voltage decreases.

Description : An aspect of Input/Output controller of data logic is called (1) General Buffering (2) Zero Buffering (3) Buffering (4) Data Buffering

Last Answer : Buffering

Description : Define Integral controller. State their advantages

Last Answer : Advantages of integral control action: 1) Improves steady state response 2) Removes offset error in the process variable. 3) Eliminates steady state error

Description : Draw and explain analog input module of PLC.

Last Answer : Analog input module are used for supplying analog input signal to PLC. Analog signals are generated by transducers, potentiometers. PLCs analog input module consists of analog-to-digital converter (ADC). ... of PLC. PLC reads the binary number and takes further decision based on the required logic 

Description : Explain the function of ROM & RAM memory of PLC. 

Last Answer : Read Only Memory (ROM) is used by PLC for storing operating system. The operating system is programmed by the manufacturer.  Random access memory (RAM) is a Read Write memory and used by ... store temporary data like status of I/O pins, temporary results of calculations, timer counter values etc.

Description : Draw the block diagram for PLC power supply and explain the function of each block.

Last Answer : PLC power supply generates the required dc voltage levels for operation of the internal circuit of PLC. It is a switched mode power supply which accepts wide range of AC/ DC input ... of power failure from AC input, Battery backup becomes active and prevents accidental shut down of PLC

Description : Define opto-isolator. Explain the role of opto-isolator in PLC.

Last Answer : Role of optoisolator in PLC: An optoisolator is a semiconductor device that uses a short optical transmission path to transfer an electrical signal between circuits or elements of a ... disruptions, optoisolators offer a safe interface between high-voltage components and low-voltage devices.

Description : Draw a neat labelled diagram of PLC. Explain the function of each block.

Last Answer : Block Diagram of PLC:-  A simplified block diagram of a PLC shown in above Fig. It has three major units/sections.  I/O (Input/Output) Modules.  CPU (Central ... membrane keypad for program entry, and a display device (LED or LCD) for viewing program steps of functions. 

Description : Explain ON delay timer and OFF delay timer of PLC.

Last Answer : On delay timer operates such that when rung containing timer is true, the timer starts counting time ticks. At the end of timer preset time period, output is made active. The off- ... is an operation to turn OFF output when preset time expires after a predetermined input is given.

Description : The law of evidence consists of (a) Ordinary rules of reasoning (b) Legal rules of evidence (c) Rules of logic (d) All the above.

Last Answer : (b) Legal rules of evidence

Description : The law of evidence consists of (a) Ordinary rules of reasoning (b) Legal rules of evidence (c) Rules of logic (d) All the above.

Last Answer : (c) Physical as well as psychological facts

Description : Draw and explain temperature measurement using RTD. State its advantages and disadvantages.

Last Answer : https://youtu.be/rYcglFW4y0I

Description : ________is also called Flash BIOS: a) PROM b) EEPROM (Electrically Erasable Programmable ROM) c) EPROM d) None of These

Last Answer : b) EEPROM (Electrically Erasable Programmable ROM)

Description : The system unit of a personal computer typically contains all of the following except: A) Microprocessor B) Disk controller C) Serial interface D) Modem

Last Answer : Answer : D

Description : The system unit of a personal computer typically contains all of the following except: a. Microprocessor b. Disk controller c. Serial interface d. Modem

Last Answer : Modem

Description : The system unit of a personal computer typically contains all of the following except: a. Microprocessor b. Disk controller c. Serial interface d. Modem

Last Answer : d. Modem

Description : The system unit of a personal computer typically contains all of the following except: a. Microprocessor b. Disk controller c. Serial interface d. Modem

Last Answer : d. Modem

Description : List the different actuators. Explain any two types of actuators with advantages and disadvantages

Last Answer : Actuators [1] Hydraulic Actuator [2] Electrical Actuator [3] Pneumatic Actuator [4] Mechanical Actuator Hydraulic Actuator According to Pascal, when there is an increase in ... efficiency Disadvantages [1] Requires more power [2] Possibilities of fire hazards / accidents

Description : Write any four points that state how a traction transformer is different from ordinary transformer.

Last Answer : Ans: 1) Specially designed to withstand severe operating conditions.  2) Are required to have high short time peak capacity.  3) Class A insulation , specially reinforced to withstand frequent short circuits.  4) Can ... effect of SC impedance not less than 8.5 % for 10 MVA and 10 % for 12.5 MVA.

Description : Drawthe PLC ladder diagram of ON-OFF control of lamp. Write the input and output devises.

Last Answer : Diagram: