Automation system power over Ethernet redundancy system and method

An automation system comprising:

• an automation component configured to perform an automation operation on a monitored and/or controlled machine or process by exchanging data or signals with an input/output device via an Ethernet network, the input/output device being at least partially powered by power from the Ethernet network;
• a PoE circuit, comprising:
• a detection circuit configured to enable detection of the input/output device;
• an isolation circuit configured to protect the input/output device from current supplied by the Ethernet network during the detection of the input/output device;
• a switch coupled to a first DC/DC converter downstream of the isolation circuit and to an auxiliary power source through a second DC/DC converter, the switch, in operation, in response to determining that power from the Ethernet network is lost or drops below an acceptable level, switches to the auxiliary power source;
• a minimum load circuit configured to maintain a minimum load on the PoE circuit to enable the detection of the input/output device while the input/output device is powered by an auxiliary power source, and the input/output device comprises a comparator circuit to substantially prevent current through the minimum load circuit when power is provided to the input and/or output device from the Ethernet network.

A method comprising:

• providing data and power to an automation input/output device via a PoE connection;
• and
• switching a power source for the automation input/output device from an auxiliary power source to a PoE source, wherein switching does not comprise restarting the powered device;
• wherein power is provided to the automation input/output device via an isolation circuit configured to protect the automation input/output device from current during the detection of the automation input/output device, and a switch coupled to a first DC/DC converter downstream of the isolation circuit and to an auxiliary power source through a second DC/DC converter, the switch, in operation, in response to determining that power from the PoE source is lost or drops below an acceptable level, switches to the auxiliary power source;
• wherein the input/output device comprises a minimum load circuit configured to maintain a minimum load on the PoE connection to enable the detection of the input/output device while the input/output device is powered by an auxiliary power source, and the input/output device comprises a comparator circuit to substantially prevent current through the minimum load circuit when power is provided to the input and/or output device from the PoE source.