12-05-2010, 09:09 PM
[attachment=3491]
[attachment=3492]
Components
The system comprises a Transmitter, converter module, float chamber, a feedline modulating control valve and an electronic microprocessor based PID/FUZZY controller.
Operation
A positive change of water level in the boiler alters the level transmitter inductance value of coil causing an imbalance in the system. This signal is transmitted through the electronic control box and connected to PID controller. Then the microprocessor-based PID level controller transmitted an electrical signal to the pneumatic positioner to position and adjusts the position of control valve.A additional low/high water level alarm or burner cut out contact are also provided in the microprocessor-based level controller with the adjustable setting position.
Operating principle:
Transmitter - Detect the water levels in the drum and send signal to the digital controller. Digital controller - With the signal given by the Transmitter and the controller will show the level on the meter (Process value) and it requite a Set Value to control the level. The signal converted and it sends to control valve to give an indication.
Control Valve - The control valve work depend on the signal given by controller and after done the job it send a feed back signal to controller for confirmation. The valve open is depending on supply air with the signal given by controller and the Positioner then adjustment opening of valve will be make.
