Demonstration of the NTC ceramic application for temperature measurement and control using the LabVIEW-based measurement system

Abstract

In the present paper, ZnO+0.01SnO₂ ceramics were prepared using a standard ceramic method. We present the NTC ceramic application for temperature measurement and control using the LabVIEW-based measurement system. The measured resistance of the sample at room temperature was about 6.5 kΩ. The electrical resistance versus temperature of the sample was measured. The negative temperature coefficient of resistance of the sample was -1.018 %/°C. This sample showed NTC effect and exhibited NTC resistor, indicating their potential application as temperature sensor with low cost. It can be used as temperature sensor by using the NTC effect. The measured temperature (T) varies with voltage drop across the sample (Vs), as shown in the eqn, T= -6.125Vs2- 29.336Vs+109. The self-heating of the sensor was negligible. The sensitivity of temperature measurement provides 3°C resolution. The experimental setup and technical aspects for oven temperature control system was presented. The apparatus described here was suitable for controlling oven in constant temperature room and operated on the principle of supplying a constant input energy that was maintained by alternately raising and lowering the input voltage between two limits. This apparatus was simple, easily obtained, and allowed of temperature control within very close limits. The aim of this paper was to introduce a system developed for measuring sample resistance versus temperature using a procedure based on virtual instrumentation. The measu rements and processing of the data were made using LP connector, a DAQ data acquisition card, computer and LabVIEW program. The system was able to store and display the data. This prepared system can, in addition, be used for oven temperature control testing. ZnO+0.01SnO₂ sample can be used as temperature measurement and control sensor. LM335 was used for calibration for measure temperature using ZnO+0.01SnO₂ sample. The operation of this sample for temperature control will use the comparison result between the measured temperature (T) and setpoint temperature (T_set). This result will control the operation of relay and solid state relay. The input power to the electric oven was controlled by solid state relay and using LabVIEW program. So, the oven temperature control system using ZnO+0.01SnO2temperature sensor and LabVIEW-based masurement system was successfully constructed and tested. This system can be used in the temperature range of 30°C to 100°C. The system has been put into operation this year and all its units have functioned well.