Pressure is the next most important parameter after Temperature. In Hydraulics and Pneumatics, the measurement, indication, control and logging-charting of pressure is indispensable.
Popular Pressure Sensors are based on either Piezoresistive or Strain-Gauge Technologies. Strain-Gauge types can be Metal Foil or Semiconductor Film.
The Analog Strip Chart Recorder is used in Simple Systems where a Record or Report has to be generated. Data Loggers and PC based Data Acquisition Systems expand this capability by making the Data Electronically Accessible for Charting-Analysis and Reporting using database applications.
The Liquid-Fluid Level in containers of uniform cross-section can be computed by measuring the pressure of the fluid head. In cases where levels of semi-volatile fluids are measured, sensors with Micro-watts of power usage or data transmission is required to protect from sparking related accidents. Even Zener Barriers can help reduce risks due to wrong connections or cross connection due to cable damages.
In the field, due to various constrains many safety practices can be overlooked or circumvented. The Sensors and System design must be over-engineered in some cases to safeguard man-machine assets.