Intrinsically safe barrier and field bus system

摘要

In a field bus system for performing communication between at least one field device and at least one higher-rank apparatus which are connected on a field bus transmission line constituted by a pair of transmission lines, an intrinsically safe barrier disposed between a hazardous area and a safe area on the transmission line in order to limit energy to be used in the hazardous area, the intrinsically safe barrier comprising impedance converting circuits provided in the barrier for reducing impedance in a frequency band of communication data.