TYPES OF CONTROL SYSTEM

1)LEVEL CONTROL SYSTEM

                                                                   Circuit Diagram

                                                                        Block Diagram
  

CONSTRUCTION

1)The liquid level control sytem is mainly consists of a tank (plant), which is filled with liquid.
2)The liquid sensor(transducer) is placed in a liquid tank, which senses the level of the liquid.
3)That sensor is connected to the transmitter.
4)Again the transmitter is connected to the controller, where the signal is to be controlled and compared with the set point value.
5) The controller is connected to the control valve, which controls the flow of liquid.

WORKING

     If the level of the liquid is increased, that level is sensed by the liquid sensor, where the liquid level is converted into electrical signal. Then the electrical signal is transmitted to the transmitter. Then transmitter passes the signal to the controller. In controller, the signal is compared with the set point value. And if the difference is more, then control valve will be closed by the controller. The liquid level of the tank will be decreased by the outlet valve until the level reaches to the set poin value.

    If the level of the liquid is decreased, that level is sensed by the liquid sensor, where the liquid level is converted into electrical signal. Then the electrical signal is transmitted to the transmitter. Then transmitter passes the signal to the controller. In controller, the signal is compared with the set point value. If the diffrence is less, then controlled valve will be opned by the controller. The liquid level of the tank will be increased until the level of the liquid reaches to the set point value.

2)FLOW CONTROL SYSTEM 

                                                                       Circuit Diagram       

                                                                        Block Diagram                

                                                      Differential pressure transducer

CONSTRUCTION

1) The flow control system is consists of a tank, where the liquid is placed.
2) It is also consists of a pipe, the orific plate is placed in the pipe.
3) That orific plate is connected to the transmitter.
4) The transmitter is then connected to the controller.
5) The controller is connected to the control valve, through which the flow of liquid is to be controlled.

WORKING     

1) If the pressure of the flow is increased, that pressure is sensed by the orific plate. The orific plate will passes that signal to the transmitter. The transmitter will transmits the signal to the controller, where the pressure signal will compared with the set point value. And if the pressure is more than the set point value, the control valve will be automatically closed by the controller. Then the flow will be decreased to the set point value.

2) If the pressure of the flow is decreased, that pressure is sensed by the orific plate. The orific plate will passes that signal to the transmitter. The transmitter will transmits the signal to the controller, where the pressure signal will compared with the set point value. And if the pressure is less than the set point value, the control valve will be opened by the controller. Then the pressure of the flow is increased near the set point value. 

3)PRESSURE CONTROL SYSTEM 

                  
                                                                   Circuit diagram

         Block Diagram 

CONSTRUCTION

1) The pressure control system is mainly consists of a chamber (plant).
2) The pressure sensor is placed in the chamber.
3) The sensor is connected to the transmitter, where the signal is to be processed.
4) The transmitter is connected to the controller.
5) The controller is connected to  the control valve, where the flow of gas is to be controlled.

WORKING 

1) If the pressure in the tank is increased above the set point value, then the present pressure in the tank is sensed by the pressure sensor. The sensor converts the pressure into the electrical signal. Then that electrical signal is processed to the transmitter, where the signal is to be measured. That signal is processed to the controller where the signal is compared with the set point value. Then the control valve will be closed and pressure is decreased to the set point value.

 2)  If the pressure in the tank is decreased , then the present pressure in the tank is sensed by the pressure sensor. The sensor converts the pressure into the electrical signal. Then that electrical signal is processed to the transmitter, where the signal is to be measured. That signal is processed to the controller where the signal is compared with the set point value. Then the control valve will be opened and the pressure will increased near the set point value.


4) TEMPERATURE CONTROL SYSTEM 

                                                                 Circuit Diagram

  
                                                                       Block Diagram 

CONSTRUCTION

1) The temperature control system is mainly consists of chamber (plant).
2) The heater and thermocouple is placed in that chamber.
3) The thermocouple is connected to the amplifier.
4) The amplifier is connected to the controller.
5) And the controller is connected to the relay. If the relay is energised, the heater is swicthed off and if the heater is doesn't energised, the heater is switched on.

WORKING

1) If the temperature is increased, then that present temperature is sensed by the thermocouple. The thermocouple converts the temp into the electrical signal. That electrical signal will processed by the sensor to the amplifier for the amplification purpose. After the amplification the amplifier transmits the signal to the controller, where the signal is measured and compared with the set point value. Then the relay gets energized and the heater will be switched off. The temperature gets decreased and controlled to the set point value.
2)If the temperature is increased,hen that present temperature is sensed by the thermocouple. The thermocouple converts the temp into the electrical signal. That electrical signal will processed by the sensor to the amplifier for the amplification purpose. After the amplification the amplifier transmits the signal to the controller, where the signal is measured and compared with the set point value. Then the relay doesn't gets energized and the temperature will be increased by switching on the heater. The temperature is increased until the temperature reaches to the set point value.  


5) CONDUCTIVITY CONTROL SYSTEM

                                                                     Circuit Diagram

                                                                         Block Diagram

 CONSTRUCTION

1) The conductivity control system is mainly consists of a electrolytic tank.
2) The electrodes(sensor) are placed in the tank, which senses the conductivity.
3) The electrodes are connected to transmitter through the cable wire.
4) The transmitter is connected to the controller, which controls the control valve.
5) The controller is connected to the control valve.

WORKING

1) If the level of the tank is increased above the set point value, that level will be sensed by the electrodes(sensor). Then the conductivity of the liquid is converted into electrical signal. That signal is processed to transmitter for the amplification purpose. That amplified signal is further processed to the controller, where the present signal is measured and compared with the set point value. Then the control valve will be closed and the conductivity level is decreased through the outlet pipe, until the conductivity reaches near the set point value.
2)If the level of the tank is decreased below  the set point value, that level will be sensed by the electrodes(sensor). Then the conductivity of the liquid is converted into electrical signal. That signal is processed to transmitter for the amplification purpose. That amplified signal is further processed to the controller, where the present signal is measured and compared with the set point value. Then the control valve will be opened and more electrolyte solution will be filled in the tank so as to increased the conductivity of the liquid.  

6)PNEUMATIC CONTROL SYSTEM

                                                           Circuit Diagram

CONSTRUCTION

1) The pneumatic control system is main consists of a flapper and nozzle.
2) The orific plate of 0.25 mm diameter is placed in the nozzle.
3) The flapper has two ends, one end is fixed, and another end is movable.
4) There is placed to the control valve in the nozzle.

WORKING

1) If the flapper moves towards the nozzle, then the input is increased. The air supply is given to the nozzle through the orific plate. since, the flapper is moves towards the nozzle, there is a restriction to the air, due to which the output is increased by reaches near the set point value.
2) If the flapper moves away from the nozzle, the input is decreased . The air supply is given to the nozzle through the orific plate. since, the flapper is moves away from the nozzle, there no any restriction to the air, due to which the output is decreased and comes near the set point value.