Reliable system for measurement and monitoring of environmental parameters

The monitoring and control of environmental conditions in fabrication areas has become an important issue due to the newest technologies that are usually very complex and very sensitive to the external influences produced by humidity, dust particles, temperature and pressure variations etc. In this context, this paper presents a data acquisition system that is capable to monitor and measure three types of environmental parameters: pressure, temperature, and humidity. The remote board containing sensors and processing circuits is connected to the PC through parallel port. The analog to digital conversion is realized with a resolution of 8 bits using the ADC0804 circuit. The systems can operate in two specific modes: monitoring and measurement. The sensors are read periodically with a selectable frequency and the selection of the sensors is realized with three signals of parallel port: STROBE for temperature, AUTOFD for pressure and INIT for humidity. The board control and the acquired data processing are realized with a LabVIEW application that is capable to simultaneously display the measured data. With minimal changes, the proposed system can be extended to operate with more types of sensors. Using a wireless transmission method between PC and remote board, the operation distance of the system can be further extended.