The basic measurement and control loop measures a process variable and determines what control action needs to be performed based on the processor’s control algorithm. The measurement path takes an analog variable (such as pressure, temperature etc) and signal conditions it in the analog domain before applying it to an ADC. The ADC provides a digital output corresponding to the value of the analog input signal relative to the reference voltage. The resolution of the converter determines the number of bits (n) in the digital representation. On the control side, the digital word from the processor is converted to an analog value using a DAC. The number of digital bits which are converted to an analog value is determined by the resolution of the DAC.