PC based temperature monitoring and alarm system

A PC based temperature monitoring and alarm system has been designed, constructed and tested. The system uses a linear and highly sensitive temperature transducer whose analog output is converted to digital format using an 8 bit analog to digital converter (ADC) before the digital signals are fed to the personal computer (PC) through the parallel port for display on the monitor. A program was written using Visual C++ which provides a user interface through which a predefined temperature limit can be set so that the threshold alarm is triggered when this limit is exceeded. A database to record the temperature readings for a certain period of time is also incorporated in the program. The device was tested within a temperature range of 25°C to 150°C while varying the threshold temperature. From the results obtained the alarm was triggered at ± 0.1°C of the selected threshold temperature. The system finds application in power plants, laboratories, workshops and domestic kitchens. The system can also be adopted for multiple zone temperature sensing such as the simultaneous temperature measurement of automobile radiators and engines and measurement of boiler temperatures in power plants.