Exam Question
(a) Describe the principles of operation of an electro-pneumatic controller. (8)
(b) Describe the principles of a fuel-air ratio controller. (8)
Class 4 (4th Engineer)
MET
📅 Sep 2022
Reference Answer
### (a) Principles of Operation of an Electro-Pneumatic Controller
An electro-pneumatic controller, often referred to as an I/P (Current-to-Pneumatic) converter or positioner, serves as a critical interface between an electronic control system (like a PID controller in a control room) and a pneumatically operated final control element (such as a diaphragm-actuated valve).
Its primary function is to convert a standard low-power electrical control signal (typically 4-20 mA DC) into a proportional, high-power pneumatic output signal (typically 3-15 psi or 0.2-1.0 bar).
**Core Components:**
An electro-pneumatic controller, often referred to as an I/P (Current-to-Pneumatic) converter or positioner, serves as a critical interface between an electronic control system (like a PID controller in a control room) and a pneumatically operated final control element (such as a diaphragm-actuated valve).
Its primary function is to convert a standard low-power electrical control signal (typically 4-20 mA DC) into a proportional, high-power pneumatic output signal (typically 3-15 psi or 0.2-1.0 bar).
**Core Components:**
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