Patent ID: 7930042

Claim:
A power supply module for a fieldbus network, comprising: a power supply for supplying DC power to a host device over a host fieldbus cable and to a field device over a field side fieldbus cable; a host side terminal to which a host side fieldbus cable can connect and a field side terminal to which a field side fieldbus cable can connect; host and field power supply paths coupling the power supply to the host side terminal and to the field side terminal, respectively; a fault detector circuit coupled to a host switch positioned along the host power supply path between the power supply and the host side terminal and to a field switch positioned along the field power supply path between the power supply and the field side terminal, the host switch decoupling the power supply from the host terminal upon detecting a fault on the host side and the field switch decoupling the power supply from the field side terminal in response to detection of a fault on the field side; and a noise filter coupled along a communication path between the host side terminal and the field side terminal, the noise filter passing bidirectional communication signals between the host side terminal and the field side terminal when no fault is present on the host side and the field side of the power supply module.