Instrumentation

Instrumentation=measure+control.
It measure the parameters which helps the process and control the process.
The basic parameters associated with process are temperature,flow level and measure.

Origin of instrumentation.

Instrumentation is the combintion of electrical,mechanical and electronics. In the first stage of instrumentation the connection between the instrument and controller were mechanical(Pneumatic connection). In pneumatic connection 3-15 psi pressure was used as signal. In 1970’sindustries started to using electrical connection between instrument and controller instead of pneumatic connection. Two types of signals are using in electrical transmission.

Analog
Digital

Analog Signal

signal which varies continously with time. From the real world itsel we can found out so many examples for analog signals. Sound,light etc.. But in the case of instrumentaton we are using 4-20 ma or 0-20 ma as analog signals. Here the voltage between controller and instrument is kept constant and taking the current as signal.

Digital Signal

Digital signal is discrete to time. Actually digitally signal is sampled from analog signal. In the conventional method they use two discreet levels for transmitting the signal from instrument to controller. Logic high And Logic low. Relays are used for implement the digital signal transmission.