How Differential Flow Meter Works? The differential flow meter is the most common device for measuring fluid flow through pipes. Flow rate and pressure differential of fluids such as gases,vapors and liquids are explored using the orifice plate flow meter. The differential flow meter venuri tube,flow nozzle or orifice plate is an inline instrument,that is …
Process Calibrators Process Calibrators are used by technicians to measure and calibrate sensors and transmitters. Using an RTD (Resistance Temperature Detector) as an example the initial step of calibration is verifying the accuracy of the temperature sensing device.To perform the measurement the process calibrator is programmed to the specific RTD type.The accuracy is determined by …
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How Control Valve Works – Animation Any Valve can be turn in to a Control Valve simply by adding an Actuator. Valve actuates in response to a signal move about to a desired position using an outside power source.These outside power sources may be in the form of pneumatic,electronics or hydraulics. Pneumatic Actuators Pneumatic Actuators …
Working Principle Of Vortex Flow-meter What is Karman Street ? A fluid flows past an object in the flow,alternating Karman Vortices are shed on the downstream side. A vortex meter comprises a meter body with a shedder bar in the flow stream.  Karman Votices are generated at the edge of shedder bar when fluid passes across …
What is a Pressure Transmitter ? A pressure transmitter is a transducer that converts pressure into an electrical signal. It outputs both analog and digital signals corresponding to the pressure. A pressure transmitter measure three phenomena : Differential Pressure,Gauge Pressure,Absolute Pressure. The most common and useful industrial pressure measuring instrument is the differential pressure transmitter. This instrument …
Electrical Protective Device A device used to protect equipment,machinery,components and devices,in electrical and electronic circuit,against short circuit,over current and earth fault,is called as protective devices. Necessity of Protective Devices Protective devices are necessary to protect electrical appliance or equipment against a)Short Circuit b)Abnormal variations in the supply voltage c)Overloading of equipment d)To protect operator against …
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PID (Proportional – Integral – Derivative ) Controller Proportional The proportional term makes the current error signal multiplied with a gain (Kp).The result will be output signal. So output signal = Kp * Error_Signal Integral The integral term makes the current error signal value and duration multiplied by with a gain (Ki). The result will …
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Override It is sometimes necessary to limit a variable in order to maintain safe operation or protect process equipment. If this variable is a function of the system’s primary controlled variable, the two variables can be interlocked in an override system. The primary variable maintains control as long as the second variable does not exceed …
Feedforward A Feedforward control system measures a disturbance in variable, predicts its effect on the process and applies corrective action. Given an exact model of the process, the feedforward controller will adjust the manipulated variable (m) so that the controlled variable (c) is unaffected by the disturbance. In fact, the controlled variable has no influence …
Cascade In cascade control system two controllers are cascaded  to each other as shown in the diagram below.  Primary controllers output is fed to secondary controller as a Set point. Both the controllers has their own sensing elements but only secondary controller gives output to the control valve. Primary controller receives set point from …