Instrumentation

Variable area meters are special form of head meters. Where in the area of flow restrictor is varied. So as to hold the differential pressure constant. The rota meter consists of a vertical tapered tube through which the metered fluid flows in upward direction. As the flow varies the ‘float’ rises or falls to vary the area of the passages that the differential across it balances the gravitational force on the ‘float’. The differential pressure is maintained constant. The position of the ‘float’ is the measure of the rate of flow.

The most common range for differential range for liquid measurement is 0-100. This range is high enough to minimize the errors caused by unequal heads in the seal chambers. It is also dependent on the differences in the temperature of the load lines. The 100 range permits an increased in capacity up to 400. While decrease down up to 20 by merely changing the range tubes or range adjustments.

Turbine meters consist of straight flow tube within which a turbine or fan is free to rotate about it s axis which is fixed along g the centre line of the tube. Mostly, a magnetic pick up system senses the rotation of the rotor through the tube walls. The turbine meter is a flow rate device

, since the rotor speed is directly proportional to the flow rate. The output is usually in the form of electric pulses from the magnetic pick up with a frequency proportional to the flow rate.

An electric potential is developed when a conductor is moved across the magnetic field. In most electrical machinery the conductor is a wire. The principle is equally applicable to a moving, electrically conductive liquid. The primary device of commercial magnetic meters consist of straight cylindrical electrically insulated tube with a pair of electrodes nearly flush with the tube walls and located at opposite end of a tube diameter. This device is limited to electrically conducting liquids. The magnetic meter is particularly suited to measurement of slurries and dirty fluids.

Pt100 is a type of Resistence temprature detector(RTD).It is made by platanium.It means 100 ohms,resistance of 0 degree c.

normally in electronics and instrumentation cct the pnp transistr is used thats y the olp is 24vlt bt in vibartion he npn transistr is used thats y v use -24vlt

Rpm means rotating per minute... We can only checking the rotating by usen of talkometer and reflecting sticke(stripes)

RTD you can measured resisitance Thermocouple you can measure millivolts.

NEMA VE2 is followed in installation of Cable tray

principle - karmans

working: biuff body is placed in pipeline. There is no flow pressure sensor getting zero. When flow in the pipe line bluff body beyond generate votices if floe is increase vortices are increased these vortices are sensed by pressure sensors and fed to transmitter generate output.

MODBUS is a commonly used industrial communications protocol. It allows the exchange of data between PLCs and computers. It was originally designed for Modicon (Schneider Electric) PLCs but has become widely used by many PLC manufacturers and industrial networks.

For pneumatic Control valve : air Lock Relay holds the Air in locked condition when the supply Air pressure falls below the set value.

Instrumentation is the variety of measuring instruments to monitoring & control a process.

Mass flow meter works on the principle of "coriols effect"

By checking the terminal block, thermoucouples should have a polarity sig or indication

Pre-commissioning and commissioning activities before a plant or facilities handed over for normal operation it should be inspected checked clean flushed verified and tested, in short pre-commissioning is the testing of non energized system and commissioning is the testing of energized system