What do you mean by sequential controllers state steps that might be present in the sequential control of a dishwasher and washing machine with system diagrams?
A sequential control system involve the sequential execution of well- defined operations that are performed in a prescribed order. Each operations or activity is called step. Each step may be an open or closed loop continues process or even a sequential sub- process.
What is a sequential control?
A control system in which the individual steps are processed in a predetermined order, progression from one sequence step to the next being dependent on defined conditions being satisfied.
Which device control the operations in sequential control systems?
Logic Controllers
How sequential control is utilized?
A Sequential Control System is used to repeat all the events in operation throughout a production cycle that consists of on/off relay logic, time delay and elapsed-time periods, predetermined counts of pulses and pulse outputs for set-point control.
What are the types of sequence control?
1) Expressions – They form the building blocks for statements. 1) Statements – The statements (conditional & iterative) determine how control flows from one part of program to another. 2) Declarative Programming – This is an execution model of program which is independent of the program statements.
Where is sequential control needed?
This type of control is required whenever the auxiliary equipment associated with a machine, such as high-pressure lubricating and hydraulic pumps, must be operating before the machine itself can be operated safely. Another application of sequence control is in main or subassembly line conveyors.
What is sequence control in PLC?
What is Sequence and Logic Control? For example, in the operation of transfer lines and automated assembly machines, sequence control is used to coordinate the various actions of the production system (e.g., transfer of parts, changing of the tool, feeding of the metal cutting tool, etc.).
What is the main difference between sequential control and process control?
Sequential control is an event-based process, in which one event follows another until a process sequence is complete. Many process control functions are sequential. Continuous control requires continuous monitoring of the process variables, so that they can be held at set levels.
What is sequential motor starting?
Sequence control allows a motor starter to be utilized as part of a complex motor control circuit that uses one set of conditions to determine the operation of another circuit. The ladder diagram shows a typical start/stop circuit with an auxiliary contact being used as a seal around the start button.
What are 3 types of motor control?
There are mainly there are three types of motor control circuits:
- Direct On Line Starter (DOL starter)
- Star Delta Starter.
- Auto Transformer Starter.
What is the reason behind starting conveyor motor in sequential manner?
Operation of each conveyor zone is initiated in a controlled sequential manner in response to when the drive motor of a conveyor zone downstream thereof reaches a predefined current draw and speed during start-up. The predefined current draw and speed for at least one conveyor zone can be different from the others.
How is across the line starting accomplished?
Across the line start circuitry is by far the most common starting circuit encountered. It is also the circuity that experience the highest current during motor starting. When the contactor coil is energized, the L1-3 contacts close and line voltage and starting current is connected directly to the stator windings.
What is the simplest starting method?
The simplest method of starting is across the line starting by connecting the motor directly to the power line this method of starting can be established.
What is meant by across the line starting?
A direct on line (DOL) or across the line starter applies the full line voltage to the motor terminals. This is the simplest type of motor starter. A DOL motor starter often contains protection devices (see below), and in some cases, condition monitoring.
What is primary resistance starting?
Primary resistance starting method is based on the reduced starting voltage concept. This method introduces the resistance in series with the stator windings of squirrel cage induction motor. Voltage drop occurs in the added resistors during starting which provides reduced voltage across the stator windings.
What is the function of the starting resistance?
Motor Starting Resistors are used to reduce the voltage at the motor terminals and also decrease the starting current. Motor Starting Resistors are necessary because the self resistance of a motor armature is very low. When the voltage is first applied, excessive current will flow.
What is the least expensive method of motor starting?
Direct-on-line
What is a resistance starter?
Slip Ring Motors are primarily used to start high inertia load or a load that requires a starting torque across a full speed range. For High Voltage wound motors, on the stator side, a High Voltage Circuit Breaker or Vacuum Contactor can be incorporated into the design. …
What is DOL starter with diagram?
The DOL starter comprises an MCCB or circuit breaker, contactor and an overload relay for protection. These two buttons, i.e. Green and Red or start and stop buttons control the contacts. To start the motor, we close the contact by pushing the Green Button, and the full line voltage appears to the motor.
What is the principle of rotor resistance starter?
Connection of extra resistance in the rotor circuit decreases the starting current and at the same time increases the starting torque. As the motor starts rotating the extra resistance is gradually cut out.