The Digital Valve Controller is smart and it is attached to the valve actuator, which controls and monitor the valve operation. The DVC is capable of operating in 4-20mA, HART, Fieldbus or Profibus protocol.
Functions of DVC:
- Reducing the deadband on the control valve
- Controlling single acting actuators and double acting actuators
- Can be used in split range applications
- Increase torque for seat load
- Make the control valve work in accordance with the command signal from the control room
- Modify characteristic flow
- Reduces slow response to control valve
- Reverse the action of the control valve
Components of Digital Valve Controller:
PWB (Printed Wire Board)
PWB can be called the brain of DVC because all settings and parameters in the control valve are stored in PWB
I / P Transducer
I / P transducer functions to convert electrical signals from PWB into pneumatic signals which are then forwarded to the relay.
Relay
The relay functions as a signal amplifier obtained from the transducer which is then channelled to the actuator to adjust the valve opening.
Magnet Feedback
Magnet Feedback functions to become a feeling media in the control valve, and then what is felt / changes that are felt by the magnetic feedback becomes feedback to DVC so that the error in the control valve can be corrected by DVC.
Working of DVC:
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DVC gets a signal from the control room, the signal goes into the PWB for processing then the electrical signal from the PWB enters the I / P transducer for conversion to pneumatic signals.
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The pneumatic signal from the tranducer goes into the relay to strengthen the pressure which then enters the actuator.
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After there is movement in the control valve, the feedback magnet reads the position of the control valve and sends the results of the reading to the PWB to be corrected if something goes wrong.
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And the correction signal is sent to the actuator via the I / P transducer and then to the relay and into the actuator so that the position of the control valve opening is more precise.
Types of DVC:
Digital valve controllers have many types from the first output to the latest types released by Emerson Process management.
DVC 2000:
Digital valve controller type 2000 is the first output, equipped with a display and push-button so that the user can calibrate the control valve directly without any additional devices such as the Hart communicator.
DVC 6000
Digital valve controller type 6000 is the second type of digital valve controllers, this type uses feedback still uses the linkage type. So the possibility of contact is still large.
DVC 6200:
This type of digital valve controllers is the same type as DVC 6000. The only difference is the feedback system that has a magnetic system, so there is no contact between the control valve and DVC.
Applications of DVC:
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Usually DVC is used in control valve and attached to control valve
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Digital valve controllers can be applied to the damper of a fan. The working system is the same, only different applications on a damper and a control valve.
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The ease of the user in setting parameters in the digital valve controllers to match the specifications of the control valve available to optimize the work of the digital valve controllers.