Multiparametric capillary sensor – stabilization of local heating

To this day, the micro-heating unit in a multiparametric capillary sensor’s setup has been controlled using laboratory power supply with constant voltage. In this method it was assumed that the micro heater’s resistance value is constant. However, due to the fact that degradation effects induced by high power density dissipation in prolonged heating cycles may cause it to vary, a new approach had to be found. Therefore, in this paper, a development of a power stabilization method using PID controller to compensate for micro-heater’s resistance changes during prolonged heating is described. Additionally, a current sensing resistor, a programmable power supply and a data acquisition system are incorporated into the setup to provide closed-loop feedback.