Application of Digitally Controlled Potentiometers in the Intelligent Sensor´s Measure and Control System

Sensor or transducers is a kind of important tool for completion of signal collection, and is a device which can feel the physical world of light, pressure, temperature, flow, level, acceleration, force, etc. Then convert this signal into usefulness output signal according to a certain law. The output of some sensors, such as piezoresistive sensor, strain sensor bridge sensor, thermocouple sensor, thermal resistance sensor, angle sensor, accelerometer sensor, humidity sensor, capacitive sensor, piezoelectric sensor etc., is very weak. Its temperature dependence and linearity are worse, and the SNR in the process of transference decrease significantly. For this disadvantage, the signals must be processed before post-processing. It can be realized by the digitally controlled potentiometers. In the fiber receiver, photodiode programmable transimpedance amplifier with digitally controlled potentiometers converts the current into voltage. Using the digitally controlled potentiometers, it can be linear that the characteristic of the platinum thermal resistance temperature sensor (including zero adjustment and full-range adjustment) and fault detect, and it can meet the request of accurate temperature measurement. The digitally controlled potentiometers also can be used in pressure measurement system to calibrate the offset voltage and full-range of the pressure sensor. Finally, the topology with feedback system constituted by digitally controlled potentiometers was provided.