Multichannel Emulator for Resistance Temperature Detectors (RTDs)

Some industries are in need of emulating banks with tens or hundreds of resistance temperature detectors (RTDs). This happens, for example, in the realization of the control electronics for big power generators employed in energy production. Unfortunately, the few RTD emulators commercially available are quite expensive, limited to few channels, and often do not present a true ohmic behavior. This work proposes a low-cost 10-b RTD emulator suitable for multichannel implementation. The proposed RTD is based on a nonstandard combination of "serial" and "parallel" resistive cells that allows the minimization of the effects of inaccuracies and parasitic elements and offers a true ohmic emulation. Mathematical models, simulations, and measurements on prototypes show that the proposed circuit emulates a temperature range between −100 and +450 °C, and it is monotonic and compliant to tolerance class "B" and/or "A" of the IEC 60751 standard.