What is the primary function of a pressure transmitter in a process control system?

The primary function of a pressure transmitter in a process control system is to measure pressure and convert it into an electrical signal that can be transmitted to a control system for monitoring and control purposes. A pressure transmitter is a sensor that is used to measure the pressure of a fluid (liquid or gas) in a process. It typically consists of a pressure-sensing element, such as a diaphragm or strain gauge, and electronic circuitry that converts the pressure measurement into an electrical signal, usually a 4-20 mA current signal or a digital signal. This electrical signal is then sent to a process controller, which uses the pressure measurement to make decisions about how to control the process. For example, a pressure transmitter might be used to measure the pressure in a vessel and send the signal to a controller that adjusts a valve to maintain the desired pressure. The transmitter allows the control system to "see" the pressure and respond accordingly.