Exam Question

### Working Principle of a Differential Pressure Transmitter
A Differential Pressure (DP) Transmitter is an instrument that measures the difference in pressure between two points and converts this measurement into a standardized output signal (typically 3-15 psi pneumatic or 4-20 mA electrical). It operates on the force-balance principle, where the force generated by the differential pressure on a sensing element is continuously balanced by a feedback force.
**Principle of Operation:**
1. **Pressure Sensing:** The transmitter has two pressure ports, a High Pressure (HP) side and a Low Pressure (LP) side. These ports are connected via impulse lines to the two points in the process where pressure is to be measured.