An industrial pressure transmitter is an industrial instrument that measures the physical pressure of a liquid or gas and converts it into a standardized electrical signal. This signal is then sent to a control system—such as a PLC (Programmable Logic Controller) or DCS (Distributed Control System)—for monitoring and process automation.
✸A differential pressure transmitter is a device for pressure measurement of gases or liquids. 

✸Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. 

✸A conservative estimate would be that there may be over 50 technologies and at least 300 companies making industrial pressure sensors worldwide.