Showing posts with the label PLC

What are PLC System Design Steps?

What are PLC System Design Steps?  PLC system design steps are: Environmental details,  Grounding and earthing,  Safety concerns networking,  Field devices and IO numbers,  Proper grouping of equipment,  Field wiring voltage level,  Program complexity and redundancy.

What is the Sequential Function Chart (SFC) PLC programming language?

What is the Sequential Function Chart (SFC) PLC programming language? Basically Sequential Function Chart (SFC) is another PLC programming language that uses graphical blocks for logic, but in SFC each block is called a step and your code will continue to execute the instructions within it until the transition condition is met. Allows logic to proceed to the next step. This concept is similar to a flow chart, hence the word chart in SFC. The decision to move to the next step of your SFC logic can be based on timing, a particular step in the process, or the physical state of the equipment. Unlike traditional flow charts, SFCs can have multiple paths (branches), and you can use branches to execute multiple steps at once. Some advantages of Sequential Function Charts are useful for large processes you can break down into major steps, easy online debugging, you can see exactly at which point your logic stopped, much faster to design your process. And some of the disadvantages of sequential

What is the Instruction List (IL) PLC programming language?

What is the Instruction List (IL) PLC programming language? Basically an Instruction List (IL) is another textual language that you can use to program your PLC, as the name suggests; You can write your reasoning in this language as a list of instructions. Each command is written on a new line. IL is a low-level language and resembles assembly. You can add any comments you want at the end of each one. Some of the advantages of Instruction List (IL) are very useful for compact code, very useful for time-critical code, very fast and consumes less memory. Some of the disadvantages of instruction lists (IL) are that they are slightly more limited in terms of structuring code, are more difficult to debug and resolve errors, are more prone to run-time errors, and can lead to infinite loops.

What is Structured List (ST) PLC Programming Language?

What is Structured List (ST) PLC Programming Language? Basically Structured List (ST) is a high-level programming language like Basic, Pascal and C. It is very powerful and well suited for complex mathematical functions and data analysis tasks. And Structured List is a text-based language, so you have to write each line of code. The ST uses functions such as IF, WHILE, FOR, and CASE. Some of the advantages of Structured List are that it is suitable for complex logic and data handling tasks, very organized and good for large mathematical calculations, more flexible than ladder logic. And some disadvantages of structured lists are that the syntax can be difficult if not familiar with high-level languages like C, difficult to debug and edit online.

What is Delta PLC?

What is Delta PLC? Basically a programmable logic controller (PLC) is a control system that uses electronic operations. And PLC has easy storage process, easy expansion principles. Delta DVP Series Programmable Logic Controllers offer high-speed, stable and highly reliable applications in all types of industrial automation machines. And it has fast logic operations with multiple instructions and multiple function cards. And this Delta PLC is economical. Also this PLC supports various communication protocols to connect AC motor drives, servos, human machine interfaces and temperature controllers through industrial networks in a complete "Delta Solution" for all users.

Ladder Diagram (LD)

Ladder Diagram (LD) A ladder diagram is also called ladder logic and originally developed from relay logic that uses devices such as switches and mechanical relays to control processes.


Relay A relay is an electrically operated switch whose purpose is to close and open circuits electronically as well as electromechanically. Relays are required to control automation systems and loads. Also Relays convert small electrical impulses into large currents using electromagnetism. These conversions occur when electrical inputs activate electromagnets and make or break existing circuits.

PLC SCADA Relationship

PLC SCADA Relationship PLCs are a part of the system that SCADA oversees. The PLCs need SCADA to control their function, but SCADA relies on data from the PLCs to complete its overview. PLC SCADA relationship is invariably powerful in creating an automated system to accurately prescribe maintenance tasks. For example, if used to monitor a turbine, the PLC may collect data that suggests there is too much vibration in the system. The PLC will transmit that data back to the SCADA software. SCADA will analyze the readouts and determine whether or not an adjustment needs to be made to the system. If a change must be made, SCADA transmits the changes back through the PLCs to facilitate the correction.

Difference between PLC and DCS

Difference between PLC and DCS PLC  PLCs are can respond to a change within one tenth of a second DCS DCS are slower than PLCs. Typical respond time of DCS is 30ms PLC  A PLC is capable of handling few hundred IOs. It can handle tens of them. DCS A DCS can handle thousands of IOs. It can handle hundreds or even thousands of analogs IOs and PID functions PLC  PLC can programmed be programmed based on our application DCS DCS comes with built in control functions that need to be configured based on the application PLC  PLCs can be made redundant with additional hardware which makes them expensive than DCS  DCS Redundancy is a default feature of distributed control systems. PLC  PLCs have a simple and flexible architecture. A PLC system consists of controllers., IO modules, HMIs and an engineering software.  DCS DCS system are less flexible. They come with controllers, IO systems, database servers, engineering and operating servers. PLC  PLCs are best suited for dedicated applications that



What is Structured Text Programming?

Structured text Structured Text is a programming language and is primarily designed for PLCs and Structured Text is ST or STX. Structured Text Language is the simplest language of PLC and this language does not need to be written for PLC programming background. And this language does not require PLC programming software to create structured text programs. Basically structured text is a text based language in which this language writes a simple text file and copy and paste into the PLC project. Structured text languages ​​have common advantages Text based language Light language No programming background required Cost effective What is Structured Text? Structured Text is the programming language of PLC and is a text based language. Basically structured text is known as ST or STX. What is the use of structured text? Basically the use of structured text is to program the PLC.

Ladder logic for controlling the running state of the single phase motor by pressing START and STOP pushbuttons

Ladder logic for controlling the running state of the single phase motor by pressing START and STOP pushbuttons

PTO function used in PLC systems

PTO function used in PLC systems   PTO (Pulse Train Output) PTO is for accurate positioning or precise velocity-control. A pulse rotates the motor by a fractional amount. Changing of frequency while duty cycle remains at 50%. T (duration) is varied. The control is done from software. The ratio of T (OFF) to T (ON) can be fixed at 50%:50%. Motion control: The open loop control of stepper motor the stepper motor amplifier ensures a constant distance increment for each pulse received. The duration of the increment is given by the frequency of the pulse. This is more familiar to use than PWM, used for stepper motors and servo motors. Position and speed can be controlled even if only open loop control is used. The Programmable Logical control provides for motion control. With the S7-1200 FW4.2 a new block is available that can set the frequency. A user program can manipulate directly the frequency. This is helpful for working speed control of variable speed drives instead of using analog co

PLC based Multi-channel Fire Alarm System

  PLC based Multi-channel Fire Alarm System Nowadays, securing one’s property and business against fire is becoming more and more important. Monitoring commercial and residential areas all-round is an effective method to reduce personal and property losses due to fire disasters. Automatic fire alarm system is widely deployed in those sites recent years. Large numbers of small fire detectors should report their information to the control center of a building or a block. This project is design and implementation of a fire alarm system using the PLC which operates the entire system. Any signal from each detector at any level is detected and monitored using monitoring system. The appliance system has components like buzzer for alarming and motor pump to stop the fire. Relay driver to make switch on/off relay according to PLC output. The entire system is controlled by PLC. The PLC is programmed in such way by using ladder diagrams. From the project done, the system can detects smoke, heat e

Programmable Logic Controller (PLC) and Supervisory Control And Data Acquisition (SCADA) Interview Question and Answers

  Programmable Logic Controller (PLC) and Supervisory Control And Data Acquisition (SCADA) Interview Question and Answers 1. What Is Plc? Answer:  PLC means Programmable Logic Controller. It is a class of industrially hardened devices that provides hardware interface for input sensors and output control element. The field I/p include element like limit switches, sensors, push button and the final control elements like actuator,  solenoid/control valves, drives, hooters etc. PLC Senses the input through I/P modules, Processes the logic through CPU and memory and gives output through output module. 2. Applications Of Plc? Answer:  PLC can be used in almost all industrial application solutions right from small machine to large manufacturing plants. Even it caters applications of redundant systems at critical process plants. 3. Explain The Role Of Plc In Automation ? Answer:  PLC plays most important role in automation. All the monitoring as well as the control actions are taken by PLCs. P

Programmable Logic Controller multiple choice questions

  Programmable Logic Controller 1. The acronym PLC stands for a) Pressure Load Control b) Programmable Logic Controller c) Pneumatic Logic Capstan d) PID Loop Controller Answer: Programmable Logic Controller 2. In PLC programming, a retentive function is one that a) Defaults to the “on” state b) Is not reset after a power cycle c) Defaults to the “off” state d) Cannot be edited or deleted Answer: Is not reset after a power cycle 3. A good application for a timed interrupt in a PLC program would be a) A communications function block b) A PID function block c) A math function block d) A motor start/stop rung Answer: A PID function block 4. In a PLC, the scan time refers to the amount of time in which   a) the technician enters the program b) timers and counters are indexed by c) one “rung” of ladder logic takes to complete d) the entire program takes to execute Answer: the entire program takes to execute 5. The difference between online and offline PLC programming is a) whether the PLC i

Programmable Logic Controllers

Programmable Logic Controllers (PLC) A PLC is known as a programmable logic controller and is an industrial computer that connects a number of I/O modules. And are commonly available in various I/O modules such as Micro PLC, Nano PLC, Medium PLC and Large PLC, basically Nano PLC has some 100 I/O modules and Large PLC has more than 5000 I/O modules. Also PLCs are available in compact type and modular type and compact type PLC has fixed size I/O and all the modules included basically compact type PLC does not increase the number of I/O modules but modular PLC has modified these I/O modules as required. A PLC has a separate module and is placed  in a rack or box type. Commonly PLC with SMPS and without SMPS. SMPS is a switch mode power supply and is also known as switching or switch mode power supply. Basically SMPS is used in PLC to convert AC supply to DC supply. And it converts 230 volt AC supply to 24 volt DC supply so PLC works on DC as well as AC supply.  And the plc response time i