A pressure sensor 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 pressure sensor usually acts as a transducer; it generates a signal as a function of the pressure imposed.

The 4-20 mA current loop is the prevailing process control signal in many industries. It is an ideal method of transferring process information because current does not change as it travels from transmitter to receiver. Since 4 mA is equal to 0% output, it is incredibly simple to detect a fault in the system.

Accuracy refers to how close measurements are to the “true” value, while precision refers to how close measurements are to each other. Accuracy describes the difference between the measurement and the part’s actual value and precision describes the variation we see when we measure the same part repeatedly with the same device.  

Precision can be broken down further into two components: Repeatability: The variation observed when the same operator measures the same part repeatedly with the same device. Reproducibility: The variation observed when different operators measure the same part using the same device.


The Math: