Research in Linearization and Anti-interference for Temperature Measurement Module with Platinum Resistance
Zhang Chuan-mi · Automation and Instrumentation · 2014
This paper analysises the reason of nonlinearity of the RTD temperature sensor for Pt100 from resistancetemperature characteristics.Using the current transmitter of XTR105,which is located on-site end,to adjust the output signal of the RTD and compensate its nonlinearity through positive feedback.After that,Output a industry standard current of 4~20 mA to the current loop receiver of RCV420 located on monitoring system side for linear conversion of current-voltage.Besides and analyses the problem of thermometry error,which is derived from DC output offset because of strong RF interference appeared in industrial field applications,and using a filter circuit to filtrate this interference in the paper. Experimental results show that the temperature measurement module can pass a series of EMC tests,which meets the requirements of most industrial field applications.After calibration,the measurement error of the module is less than 0.5 ℃.