Abstract: A pumping unit remote monitoring system's concentrator applied to oil fields designed by using Two way Automatic Communication System (TWACS). The principle of modulating around voltage zero point is used, and the TWACS carries message by modulating weak distortions on the voltage and current waveforms around voltage zero point so as to realize the two way communication. The real time remote monitoring is realized for all kinds of electric parameters and fault alarm of pumping unit electrical Machinery. The test run in oil field shows that this concentrator can meet the needs of visualized measurement and accuracy target.