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What is DCS? (Distributed Control System)

The DCS is a system of sensors, controllers, and associated computers that are distributed throughout a plant. Each of these components serves a different function, such as data acquisition, process control, data storage, and graphical display.

The plant's local area network – also known as a control network – connects these individual elements to a centralized computer. The DCS, as the plant's "central brain," makes automated decisions based on production trends that it sees in real-time throughout the plant.

For example, a power plant's DCS may automatically increase the capacity of multiple turbines to meet changing demand for electricity during hot summer days, and then decrease it as outdoor temperatures cool overnight and demand decreases. Whereas a PLC can only change a single unit operation, a DCS can change all of a plant's interacting unit operations.

In recent years, the use of smart devices and field buses has increased the prominence of distributed control systems (DCS) in large and complex industrial processes, as opposed to the previous centralized control system. This distribution of control system architecture throughout the plant has resulted in more efficient ways to improve control reliability, process quality, and plant efficiency.

Nowadays, distributed control systems can be found in a wide range of industrial fields, including chemical plants, oil and gas industries, food processing plants, nuclear power plants, water management systems, automobile industries, and so on.

How DCA is used?

While DCSs are used in many process control industries to supervise complex production processes, they are most commonly found in large, continuous manufacturing plants such as those in the petrochemical industry.

These and other manufacturers can efficiently coordinate adjustments in a top-down fashion using a centralized network of computers with the help of a DCS. DCS instructions are distributed throughout a plant and fed to individual controllers. When properly configured, the DCS can improve safety while also increasing production efficiency.

Working and operations of DCS system –

DCS works as follows: sensors sense process information and send it to local I/O modules, to which actuators are also connected to control process parameters. The information or data from these remote modules is collected and transmitted to the process control unit via field bus. When smart field devices are used, the sensed data is sent directly to the process control unit via the field bus.

The collected data is then processed, analyzed, and output results are generated based on the control logic implemented in the controller. The outcomes or control actions are then transmitted to the actuator devices via the field bus. As previously stated, DCS configuration, commissioning, and control logic implementation takes place at the engineering station. At operation stations, the operator can view and send control actions manually.

Architecture of DCS –

DCS has three main characteristics, as the name suggests. The first is the division of various control functions into relatively small sets of semiautonomous subsystems that are linked by a high-speed communication bus. These functions include data acquisition, data presentation, process control, process supervision, information reporting, and information storage and retrieval.

The second feature of DCS is the automation of manufacturing processes through the integration of advanced control strategies. The third characteristic is the ability to organize things as a system. DCS organizes the entire control structure as a single automation system in which various subsystems are unified through a proper command structure and information flow. 

These characteristics of DCS can be seen in the architecture displayed in the diagram below. A DCS's basic components include an engineering workstation, an operating station or HMI, a process control unit or local control unit, smart devices, and a communication system.

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In this Info Graphic , you can learn about DCS - Distributed Control System and How DCS is used. 

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What is SCADA?

SCADA stands for supervisory control and data acquisition, and it is a software and hardware system that enables industrial organizations to:

1.   Local or remote control of industrial processes

2.   Real-time data is monitored, gathered, and processed.

3.   Interact directly with equipment such as sensors, valves, pumps, motors, and others using human-machine interface (HMI) software.

4.   Create a log file to keep track of events.

SCADA systems are critical for industrial businesses because they help to maintain efficiency, process data to make better decisions, and notify system faults to save downtime.

The basic SCADA design begins with programmable logic controllers (PLCs) or remote terminal units (RTUs). PLCs and RTUs are microprocessors that communicate with a variety of items, including factory machines, HMIs, sensors, and end devices, and then transport data from those objects to computers using SCADA software. The SCADA software analyses distributes, and displays data, assisting operators and other employees in making vital decisions.

For instance, the SCADA system can instantly alert an operator if a batch of products has a high rate of defects. To identify the cause of the problem, the operator pauses the activity and utilizes an HMI to view the SCADA system data. When the operator examines the data, he finds that Machine 4 was not working properly. The capability of the SCADA system to warn the operator of an issue helps him in resolving it and preventing additional product loss.

Who uses Scada?

SCADA systems are used by industrial organizations and businesses in both the public and private sectors to control and maintain efficiency, distribute data for better decision-making, and notify system faults to help reduce downtime. SCADA systems are useful in a variety of businesses since they can range from simple settings to big, complex installations. Many modern industries rely on SCADA systems, including the following:

Energy

Food and beverage

Manufacturing

Oil and gas

Power

Recycling

Transportation

Water and waste water

And many more

 In today's world, SCADA systems can be found virtually everywhere: maintaining the refrigeration systems at your local supermarket, guaranteeing production and safety at a processing plant, meeting quality standards at a waste water treatment plant, or even tracking your energy use at home.

Effective SCADA systems can save time and money. There have been numerous case studies published showing the advantages and cost savings of utilizing a modern SCADA software solution like Ignition. 

Modern SCADA system-

Modern SCADA systems enable remote access to real-time data from the plant floor. Governments, corporations, and individuals may use real-time data to make data-driven decisions about how to improve their processes. Without SCADA software, gathering enough data to make consistently well-informed decisions would be extremely difficult, if not impossible.

Furthermore, most recent SCADA designer products include rapid application development (RAD) features, which enable users to create systems quickly even if they lack considerable software development knowledge.

SCADA software has substantially improved in terms of efficiency, security, productivity, and dependability since the introduction of modern IT standards and techniques like SQL and web-based applications.

SCADA software that makes use of SQL databases has a lot of advantages over older SCADA software. One of the biggest benefits of using SQL databases with a SCADA system is that it's much easier to interface it with current MES and ERP systems, allowing data to flow more smoothly throughout a business. 

Historical data from a SCADA system can also be stored in a SQL database, making data analysis and trends easier.

Components of SCADA systems-

SCADA systems consist of field-deployed components that collect real-time data, as well as related systems that facilitate data collection and improve industrial automation. The following are examples of SCADA components:

 1. Sensors and actuators- A sensor is a component of a device or system that detects industrial process inputs. An actuator is a component of a device or system that controls the process mechanism. A sensor is similar to a metre that shows the status of a machine, whereas an actuator is similar to a switch, dial, or control valve that can be used to control a device. SCADA field controllers control and monitor both sensors and actuators.

2. SCADA field controllers - These are in direct contact with sensors and actuators. Field controllers are divided into two types:

-      Remote telemetry units, also known as remote terminal units (RTUs), connect to sensors to gather data and send it to a core system for processing.

-      PLCs connect with actuators to control industrial processes, which are often based on current telemetry gathered by RTUs and the standards established for the processes.

3. SCADA Supervisory computers- These are in charge of all SCADA activities, and they collect data from field devices and give commands to those equipment in order to regulate industrial processes.  

4. HMI Software- This creates a system that gathers and displays data from SCADA field devices, allowing operators to understand and, if necessary, modify the status of SCADA-controlled processes.

5. Communication infrastructure- This allows supervisory control and data acquisition systems to interface with field devices and controllers. SCADA systems may collect data from field devices and control them using this infrastructure.

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SCADA and its Components

This Info Graphic explains what is SCADA and its Components. If you want to learn more about SCADA. 

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What is an HMI?

A user interface or dashboard that connects a human to a machine, system, or device is known as a Human-Machine Interface (HMI). Although HMI can technically refer to any screen that allows a user to interact with a device, it is most usually associated with industrial processes. Although Human-Machine Interface (HMI) is the most frequent name for this technology, it is also known as Man-Machine Interface (MMI), Operator Interface Terminal (OIT), Local Operator Interface (LOI), or Operator Terminal (OT). HMI and Graphical User Interface (GUI) are related but not the same thing: HMIs frequently use graphical user interfaces (GUIs) to provide visualization capabilities.

HMIs can be utilized in a variety of ways in the workplace, including:

Visualize data

Keep track of production times, trends, and tags.

Monitor KPIs

Keep track of the machine's inputs and outputs.

And much more

A plant-floor operator might use an HMI to check and regulate the temperature of an industrial water tank, or to see if a specific pump in the facility is currently working, similar to how you might interact with your air-conditioning system to check and adjust the temperature in your home.

HMIs come in a variety of formats, from built-in screens on machines to computer monitors to tablets, but their goal remains the same regardless of the format or term used to refer to them: to provide insight into mechanical performance and progress.

Who Uses HMI?

HMI technology is utilized by almost all industrial organizations, as well as a wide range of other businesses, to interface with their machines and enhance their industrial processes.

Industries using HMI include:

Energy

Food and beverage

Manufacturing

Oil and gas

Power

Recycling

Transportation

Water and waste water, and many more

Operators, system integrators, and engineers, particularly control system engineers, are the most common positions that interact with HMIs. For these specialists, HMIs are critical tools for reviewing and monitoring processes, diagnosing problems, and visualizing data.

Developing Trends in HMI Technology-

Changing operational and corporate needs have prompted interesting improvements in HMI technology during the last decade. Along with more classic models, advanced kinds of HMI such as high-performance HMIs, touch screens, and mobile devices are becoming more popular. More chances for equipment interaction and analysis are being created by these upgraded interfaces.

1. High performance HMI – High-performance HMI, a type of HMI design that helps in fast, effective interaction, is becoming increasingly popular among operators and users. This design strategy helps the viewer in seeing and responding to problems more effectively, as well as make better-informed judgments, by only drawing attention to the most necessary or critical indicators on the interface. High-performance HMI indicators are basic, clean, and purposefully devoid of any unnecessary images or controls. Colour, size, and placement, among other design components, are utilized sparingly to improve the user experience.

2. Touch Screens and Mobile Devices – Touch displays and mobile HMI are two examples of technology advancements made possible by smartphones. Instead of buttons and switches, modern HMIs allow operators to access controls by pressing or touching the physical screen. Touch displays are especially significant when it comes to mobile HMI, which can be delivered via web-based HMI/SCADA or an app. Users benefit from mobile HMI for a variety of reasons, including rapid access to HMI data and remote monitoring.

3. Remote monitoring – Operators and managers benefit from mobile-friendly remote monitoring since it gives them more flexibility and access. An offsite control system engineer, for example, can utilize this capability to confirm the temperature of a warehouse on a portable device, removing the requirement for onsite supervision after business hours. Checking in on a process on your factory floor while thousands of kilometers away will soon become routine.

4. Edge-of-Network and Cloud HMIs – Operators want edge-of-network HMIs because they give them access to data and visualization from field devices. Additionally, sending data from local HMIs to the cloud, where it can be accessed and analyzed remotely while maintaining control capabilities local, is becoming more prevalent.

5. Peering into the future of HMI – Leading engineers are even looking into ways to use Augmented Reality (AR) and Virtual Reality (VR) to visualize industrial functions in the future. The future of HMI appears to be bright since data plays an increasingly important role in production. This technology has come a long way, but it still has a lot of potential for improvement.

Common uses of HMI -

To get and display information for users, HMIs interface with Programmable Logic Controllers (PLCs) and input/output sensors. Depending on how they are implemented, HMI screens can be used for a single purpose, such as monitoring and tracking, or for more complex actions, such as shutting machines off or raising production speed.

HMIs are used to improve an industrial process by automating and coordinating data for a viewer. Operators can monitor important data in graphs, charts, or digital dashboards, view and handle alarms, and interface with SCADA and MES systems all from a single console using HMI.

Previously, operators had to walk the floor regularly to check on mechanical progress and record it on paper or a whiteboard. HMI technology eliminates the need for this outdated practice by allowing PLCs to convey real-time data directly to an HMI display, reducing numerous costly problems caused by a lack of knowledge or human error.

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Learn what is an HMI and its common uses. 

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Timer in PLC and its types

 A PLC timer is an electrical system component used in ladder logic programming. Timers are devices that count time divisions.

A PLC timer is a program that controls and operates a device for a set period. We can use the timer to do any certain activities for a fixed period.

A timer is one of the most important and helpful entities. With the help of a PLC programming timer order, you can build up a time-based action. Each PLC has a unique set of timer functions.

The timer instruction is used to provide programming logic and to decide when to switch on or off the circuit. It contains two types of contacts: normally open (NO) and typically closed (NC).

On connection or instant disconnection, the timer causes a delay in both PLC programming and relay boards.

Simply stated, when the input is turned on, the timer begins to run and keeps track of the time. The timer activates its output when this time exceeds the programmed time.

In the programming of the Ladder Diagram (LD) PLC, you could specify the timer from milliseconds (ms) to hours (hr).

Here are some of the key terms to know about timers in PLCs:

1. Input and Output Modules-

In the PLC system, there are several input (I) and output (O) modules. They serve as a link between the CPU and programmable devices. Input Module refers to the component that interacts with the input signal. It is necessary to connect input devices such as different types of switches. Output Module refers to the component that interacts with the output signal. The output module is necessary for connecting output devices, such as electric applications.

2. Power Supply Module-

The power module supplies electricity to the timing circuit, which allows it to function properly. It can be connected to either an ac (120, 230 V AC) or a dc voltage source (like 5,12, 24 V DC).

3. Internal Timer Circuit-

The set and reset functions are performed by the timer circuit. The timer will provide the momentary input pulse for the set and reset operation if the auxiliary power source is turned on. 

4. Timer Digital Display-

The set and elapsed timing values are displayed on the digital timer. Values can be shown in a few milliseconds for automated purposes (ms). This will make tracking your automation system simple.

Different types of PLC Timer:

1. On Delay Timer-

Timers are the most commonly used timer in electric circuits. You may be familiar with the term "on delay," which means "delayed on." It means that the timer will not update the contacts until the preset time has passed. These timers are used in Star-delta starter, capacitive load starter etc.

As you can see in the diagram, the input supply is delivered, but there is no output until the predetermined time has passed. The contact changeover occurs when the timer reaches the preset time. Such Timers are called on delay timers.

2. Off Delay Timer (TOFF)-

You may recognize the term "off-delay = delayed off" from the word itself. This means that even if the timer's input power is turned off, the timer continues to give contacts to the exiting circuit.

As shown in the diagram, the input signal is turned off, but the contact remains closed. Such timers are called off delay timer. These off delay timers are used in motor cooling systems.

3. Retentive On/Off Timer (RTO)-

The RTO's primary function is to hold or store the set (accumulated) time. RTO is used when the rung status changes, there is a power outage, or there is a system disruption.

Applications of Timer:

Here are some of the most common timer applications in a PLC automation setting:

1. Use for the delay action.

2. It's used to start and stop operations according to the user's instruction.

3. The RTO timer is useful for storing or recording intermediate time values.

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Learn what it timer in plc and its types. There are 3 types of timer in plc- on delay, off delay and retentive on/off timer. 

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What is a Contactor?

A contactor is an electrical device that is used to turn on and off an electrical circuit. It is regarded as a unique sort of relay. The main difference between a contractor and a relay is that the contractor is utilized in applications that require a larger current carrying capacity, whilst the relay is used in situations that require a lower current carrying capacity. Contactors are small and easy to install in the field. These electrical devices usually have many contacts. When the contactor coil is powered, these contactors are generally open and give operating power to the load. For the most part, contactors are used to regulate electric motors.

Contactors come in a variety of shapes and sizes. Each type has its own set of characteristics, capabilities, and uses. Contactors can handle currents ranging from a few amperes to thousands of amperes, as well as voltages ranging from 24 VDC to thousands of volts. Moreover, these electrical devices come in a multitude of sizes, – from small hand-held devices to all those measuring a meter or yard on one side (approximately).

The contactor is most commonly used in high-current load applications. Contactors are well-known for their capacity to manage currents of more than 5000 amperes and high power of more than 100 kW. When a large motor current is interrupted, it produces arcs. These arcs can be decreased and controlled with a contractor.

Contactor Components-

The contactor is made up of three essential components:

1. Coil or Electromagnet: This is the most essential part of the contactor. The coil or electromagnet of the contactor offers the required driving force to close the contacts. An enclosure protects the coil or electromagnet and its contacts.

2. Enclosure: Contactors, like any other device, have an enclosure that provides insulation and protection against personnel touching the contacts. Polycarbonate, polyester, Nylon 6, Bakelite, thermosetting polymers, and other materials are used to construct the protective enclosure. In most instances, an additional enclosure is built to the open-frame contactor to protect it from severe weather, explosion threats, dust, and oil.

3. Contacts: This is another vital part of this electrical device. The contacts are currently performing the contactor's carrying role. In a contactor, there are mainly three types of contacts: contact springs, auxiliary contacts, and power contacts. Each type of contact has a certain function to perform.

Different Types of Contactor Devices-

1. Knife Blade Switch- In the late 1800s, the knife blade switch was introduced. It was most likely the very first contactor used to control (start or stop) electric motors. The switch was made out of a metal strip that slid across a contact. This switch had a lever that could be used to pull the switch down or up. The knife blade switch had to be lowered into the closed position by standing next to it back then. However, there was an issue with this way of switching. Because it was difficult to manually open and close the switch fast enough to avoid arcing, the contacts wore out quickly. As a result, the soft copper switches began to rust, increasing susceptibility to moisture and filth. The size of the motors became larger over time, requiring the use of larger currents to operate them. As a result, operating such high current carrying switches could be dangerous, posing a major safety concern. Despite the number of technical advances, the knife blade switch was never fully developed due to the challenges and risks of dangerous operation as well as the contacts' short life.

2. Manual Contactor- Engineers created a new contactor device after the knife blade switch became potentially unsafe to use. This contactor device included several functions that the knife blade switch lacked. This device was described as a manual controller. 

These characteristics included:

Operation is risk-free

A unit that is not visible and is appropriately enclosed

Smaller in size

Contacts with single breaks have been replaced by contacts with double    breaks

3. Magnetic Contactor- The magnetic contactor is operated electromechanically and does not require human interaction. This is one of the most advanced contactor designs available, and it can be remotely operated. As a result, it reduces the dangers of running it manually and placing operational staff in danger. The magnetic contactor only requires a small amount of control current to open or close the circuit. In industrial control applications, this is the most common type of contactor. 

How Does the Contactor Work?

The electromagnet is activated by the current that flows through the contactor. The contactor core moves the armature due to the magnetic field produced by the excited electromagnet. The circuit between the fixed contacts and the movable contacts is completed by a normally closed (NC) contact. This allows current to flow from the contacts to the load. The coil de-energizes and closes the circuit when the current is released. Contactor contacts are recognized for their quick opening and closing action.

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Learn what is a contactor and its components. There are 3 essential components of contactors- Coil or Electromagnet, Enclosure and Contacts.

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What is Direct Online Starter?

The DOL starter is a kind of motor starter that connects the electric engine straightway to the line voltage. It's the simplest and cheapest approach to start an induction motor. In the DOL launch, the outstations of the motor are connected to the powerful force through a contactor and overload safeguard device. 

Although DOL starter is the most frequent starting approach accessible on the demand, it's meaningful to reflect that it has some limitations. The starting current of an induction engine is 6 to 8 times higher than the rated current when straightway connected to the power supply voltage. The control of current and torque isn't achievable. For this reason, large power motors cannot be competent to start with this system.

A wiring diagram of Direct Online Starter :

The DOL starter attaches the engine immediately to the main supply line of the device connected, the motor draws a high amount of current compared to the full loading current of the motor (up to 6-8 times advanced). The valuation of this bulky current decreases as the motor reaches its rated speed.

A DOL starter can exclusively be implemented in situations when the high flow current of the engine doesn't generate an intolerable voltage drop in the force circuit. However, a star-delta starter should be used rather, if a high voltage drop needs to be avoided. Direct online starters are generally used to start fragile engines, especially 3 phase squirrel cage induction engines.

The protection offered by DOL Starter-

The Motor starters not exclusively give the safe starting current but also give protection to keep the engine all right during operation. It's crystal clear that the DOL starter provides the full line voltage but it does give the following protection.

The overcurrent condition can generate damage to the engine, power lines and can be a threat for operators. Such a quantum of current is too hazardous for a brief occasion.

In the DOL starter, we apply a circuit breaker or fuses for security against overcurrent. They unclose the circuit and break the current inflow in a moment until the challenge in the system is resolved. The fuse or circuit breaker is precisely named with its degree kept in mind. Because we don't demand the fuse to break up but to permit the starting current as well as the heavy load current. The overcurrent breaker’s standing is kept a bit advanced than the rated starting current of the motor.

Overload Protection-

The condition where the load connected to the motor increases beyond its limitation and the engine draws an extreme quantum of current is called overload condition. During load, the current inflow is beyond the safe boundaries which damages the cables as well as the motor windings. It melts the windings and may invoke fire threats. To safeguard the motor from overloading, we apply an overload relay that trips the power supply and protects the system from overheating. The overload relay monitors the current and breaks the current inflow when it exceeds some limit for a period of moment. The tripping mechanism may differ and depends on the operation of the motor.

Different Types of Overload Relays used for motor protection-

1. Thermal Overload Relay- This class of overload relay works on the principle of expansion due to the heat generated by the current inflow. A bimetallic strip is employed with distinguishable thermal expansion to break up or form the circuit grounded on the temperature.

2. Magnetic Overload Relay- Similar relays of this type work on the principle of the magnetic field generated by the current inflow through a coil. An intolerable current drawn by the engine (that is a predetermined quantum) generates enough magnetic field to trips the contact outstations and breaks the current supply.

3. Electronic Overload Relay- An electronic relay is a solid-state device without any portable region or connections. It utilizes current detectors to cover the motor current and has an adjustable setting that allows the tripping at a wide range of current rankings.

Construction of DOL Starter-

A DOL or Direct Online starter has exclusively two push buttons; Green and Red, where the green button is employed for starting and the red is employed for stopping the motor. The green button connects the outstations and closes the circuit while the red button disconnects the outstations and breaks the circuit.

The DOL starter is manufactured of a circuit breaker or MCCB or fuse, a load relay, and a contactor or coil. The circuit breaker is used for security against short circuits while the overload relay protects the engine from overfilling. The contractor is utilized for starting and stopping the engine where the green and red buttons are compounded.

Parts of DOL Starter-

1. Circuit Breaker or Fuse- The circuit breaker or fuse is straightway compounded to the power mains and it's used for protection against short circuits. It trips the power supply in case of a short circuit to safeguard the system from any possible hazards. 

2. Magnetic Contactors- A magnetic contactor is an electromagnetic switch that operates electromagnetically to exchange the power supplied to the engine. It connects and disconnects multiple connections accessibly by supplying remote control over the operation. The magnetic field generated by the coil is harnessed for switching the terminals. The passing current through the coil magnetizes the iron core that's encircled by the coil. The magnetic force pulls on the armature to close or open the connections. 

3. Overload Relay- OLR or load relay is the last part used in the DOL starter and it's used for protection against overloading of the motor. It breaks the current inflow when it exceeds a certain limit but it also tolerates the high starting current. So the OLR is precisely named in such a way that its tripping current limitation doesn't tumble below the starting current range.

Principle of DOL Starter-

The Direct Online starter works on full voltage or across-the-line methodology where the engine is directly compounded to the full voltage supply. Since there's no voltage deduction, the starting current is genuinely high which leads to high starting torque.

When the engine starts, it'll drag a huge current generally 5 to 6 times that of its rated full speed current. The huge current draw will effectuate a dip in the line voltage. The gradational increment in the speed will drop the current drawn from the lines but not below a certain speed (typically at 75). Once the engine reaches its rated speed, the current drawn and the line voltage will return to normal.

Also, keep in mind, the jumping current may harm the windings of the motor. Therefore, motors having a low power rating are connected through the DOL starter.

Advantages of DOL Starter- 

1. Simple to design

2. Easy to operate and maintain

3. Cheapest and Economical

4. Provides 100% starting torque

5. Troubleshooting and understanding the system is easier.

6. Connects the delta winding of the motor. 

Disadvantages of DOL Starter-

1.  Starting current is very high.

2. Starting current can damage the motor

3. The high inrush of current causes a voltage drop in the lines that can be connected to other appliances.

4.  High starting is torque unnecessary in many cases.

5.  High starting torque produces mechanical stress which reduces the life span of the motor.

6. There is no control over the starting current and torque.

Features of DOL Starter- 

1. Provides high starting current.

2. Provides high starting torque.

3. Produces voltage dip in the power mains.

4. Simplest controlling mechanism.

5. Suitable for low power rated motor. 

Applications of DOL Starter- 

1. The DOL starters are used in motors having low power ratings.

2. Starting current does not cause huge dips in the line voltage.

3. DOLs are used for small water pumps, conveyor belts, compressors, and fans.

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What is Direct On Starter?

This infographic explains what is DOL starter and its principle.  The DOL starter is a kind of motor starter that connects the electric engine straightway to the line voltage. It's the simplest and cheapest approach to start an induction motor. In 

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What is Star-Delta Starter?

Star-Delta Starter is the most commonly used method that reduces the starting current and starting torque of an electrical motor.  The star/delta are used in an attempt to reduce the start current applied to the motor for reducing the trouble and intervention on the electrical supply.  Star/delta are consist of three contactors- An overload relay or circuit breaker and a timer. For the functioning of the delta starter, a motor must be connected to the delta.  In the star-delta starter, starting current is 33% during direct online start, and starting torque is reduced by about 33% of the torque available at a direct online starter. 

Types of Star-Delta Starter -

There are 3 types of star-delta starter:

1. Manual Star-Delta Starter - Manual star delta is a perfect solution for Oil mills, Flour mills and Agro Industries. It gives assurance of same dependability and protection.

2. Semi-Automatic Star-Delta Starter - These starters work with a 3-push button system. The third push yellow button is used to change the sequence of the running motor from Star to Delta. To protect against overloading and single phasing problem bimetallic thermal overload Relay is fitted in these starters.

3. Fully Automatic Star Delta Starter (wye delta) - These starters work automatically with the help of the timer fitted inside the starter. The time period can be adjusted between 7 to 15 sec.

Star-Delta Starter working principle: 

1. When Star/Delta motor starts working, the start-up of the three-phase induction motor is applied by a changeover of windings.  2. All 6 winding connections are attached to the main supply with the help of Star-Delta Switch and, jumpers in the motor terminal box are excluded.  3. The windings of the motor are connected throughout the operating connection.  4. The winding voltage (WV) must be equal to the phase voltage of the three-phase system. 5. In a star connection, the mains voltage (ULN) on the individual motor windings is lower by a factor of 0.58.

Advantages of Star-Delta Starter: 

Star Delta-Starter are widely used because of their low price. 

There is no limit on operating them. 

The components of star/delta do not require much space. 

It reduces mechanical stress on the motors. 

The operating function of star/delta is simple.

Disadvantages of Star-Delta Starter: 

The star/delta can only be applied to motors where the six leads and terminals can be accessed. 

Once the starting torque is reduced to 33% it cannot be adjusted. 

There are many devices and much wiring. 

It requires higher maintenance. 

When the starting current is reduced to approximately one-third of the rated current, the starting torque is also reduced to one-third. 

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What is Star-Delta Starter?

This infographic explains what is Star-Delta Starter and its three different types. Star/Delta Starter comes under the PLC program. Manual Star Delta Starter, Semi-Automatic Star Delta Starter and Fully Automatic Star Delta Starter, these three types are explained in an above image

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What is Level Sensor and How does it works?

What is Level Sensor? 

A level sensor is a tool that is used to monitor, maintain and measure liquid levels that flow in an open system or closed system. Once the liquid level is measured, these sensors helps in converting received data into an electric signal. Level sensors are primarily used in the manufacturing and automotive industries, but are also used in many household appliances.

There are two Types of  Level Sensors- 

1. Point Level Sensor- 

Point level sensors are used in measuring the liquid at a certain point in a tank or a chamber. These sensors are mainly used to managed high and low levels of liquid. Most of the time, they work as a switch to engage a function when the tank level is either rises or falls to a certain level. The sensor detects when the liquid has reached the expected point and it moves as a switch to activate the necessary response.

2. Continuous Level Sensor- 

Continuous level sensors are used to give liquid level detection through every point in the tank or a chamber. In simple words, it is a transmitter that calculates liquid within a specified range that controls the same amount of liquid within the limited area. These sensors come in both vertical and horizontal mount transmitters that are perfect for monitoring the liquids in tight and restricted areas.

How does level sensor works- 

1. Level sensors are put into a certain depth in the liquid to be measured. After putting these sensors into the liquid, the pressure on the sensor’s front surface transfers into the liquid level height.  2. The calculation formula for measuring the level of liquid is- P=ρ.g. H+Po.  3. Here, P stands for Pressure on the liquid surface of the sensor, ρ stands for the density of the liquid to be measured, g is for local acceleration of gravity, H is for depth at which sensor drops into the liquid and Po is the atmospheric pressure on the liquid surface.

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This info graphic gives the information about what is Level sensor and how does it work. All the information is explained in very simple language. 

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What is sensor and What are the types of sensors?

What is Sensor?

A sensor is a device that helps to make advancements in electronic quantities and physical quantities and other quantities. It shall result in making progress by affirming yield. In Industrial automation, sensors play very important role by making the products intellectual and unusually automatic.

Different Types of Sensors used in Industrial Automation- 

Temperature     Sensor

Pressure     Sensor

MEMS     Sensor

Torque     Sensor     

1. Temperature Sensor- 

A temperature sensor is a device that helps in collecting the information regarding the temperature from a resource and it changes in such a form which can be understood by another device. 

Digital temperature and humidity & temperature sensors are two main sensors that are used in automation.

Digital     Temperature Sensor: 

Digital temperature sensors are silicon-based temperature sensing ICs that gives the exact output through the digital representation of temperatures they are measuring. This helps in making simple control system’s design.

Humidity     and Temperature Sensor: 

These devices are used to give the actual humidity condition within the air at any given time or a place. Such devices are of most use where the air condition is extreme or it need to be controlled that are caused by different reason. By using these sensors, it gives a surety of high consistency and exceptional long standing stability.

2. Pressure Sensor- 

Pressure sensor is a device that catches the pressure and manages to change it into an electronic signal where the quantity depends upon how much pressure appealed.

3. MEMS Sensor-

MEMS sensors helps in converting measured mechanical signals into electrical signals.

 Acceleration and Motion MEMS are two types used most in Industrial Automation.

4. Torque Sensor- 

Torque sensors is defined as transducer used for torque measurement (torque sensing) that transforms an input mechanical torque into an electrical output signal. This sensor is also commonly known as Torque transducer, Torque cell, Torque tester, Torque gauge and Moment sensor.

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