In a process industry, controls of process variables are required for production. These process variables are level, pressure, temperature, humidity, and flow, etc. In order to maintain these variables, measurements of these variables become important. Instrumentation products are used to measure, monitor and control these process variables. Pneumatic Instrumentation products include Positioners, regulator, relays, electro-pneumatic transducers, pressure switch, flow switch, sensors, solenoid valves, etc. Pneumatic instrumentation products need filtered and dry air. Hence compressed air must be prepared by using filters and dryers before using it for instrumentation products operation. For instrumentation purpose normally regulators with specific consideration as per the application are used. The instrumentation product manufacturer has instruments, in order to control and monitor a certain process.