# US 10,873,264 B2 · Automation system power over Ethernet redundancy system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,264 B2 - Document ID: US10873264B2 - Status: Granted - Kind: B2 - Application number: 15/624,253 - Filed: 2017-06-15 - Published: 2018-12-20 - Granted: 2020-12-22 - Earliest claimed: 2017-06-15 - Assignees: Rockwell Automation Technologies, Inc. - Applicants: Rockwell Automation Technologies, Inc. - Inventors: Gary D. Dotson - Web page: https://patentgrep.com/patent/US10873264B2 ## CPC - H02J 9/061: {for DC powered loads} - H02M 3/33523: {with galvanic isolation between input and output of both the power stage and the feedback loop} - H04L 12/10: Current supply arrangements - H02J 1/00: Circuit arrangements for DC mains or DC distribution networks - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract There is provided a powered device configured to switch between a power over Ethernet (PoE) source and an auxiliary power source without restarting the device. A PoE circuit within the device includes a minimum load circuit which enables detection of the device by PoE power sourcing equipment (PSE) even when the device is powered by the auxiliary power source. The minimum load circuit may maintain a load of around 10 mA to simulate powered components, thereby enabling the PSE to reinitiate PoE even though the powered components of the device are at that time powered by the auxiliary power source. When the power supplied to the powered components by the PSE overcomes that of the auxiliary power source, the power scheme may automatically revert to PoE. ## Claims ### Claim 1 An automation system comprising: a monitoring and/or control component configured to control a machine or process; an Ethernet network coupled to the monitoring and/or control component for exchanging data during operation of the machine or process; an input and/or output device coupled to the monitoring and/or control component via the Ethernet network that, in operation, provides data to or receives data from the monitoring and/or control component via the Ethernet network and that is powered by the monitoring and/or control component via a PoE scheme during operation; an isolation circuit configured to protect the automation component input and/or output device from current supplied by the monitoring and/or control component during the detection of the input and/or 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 Ethernet network is lost or drops below an acceptable level, switches to the auxiliary power source; wherein the input and/or output device comprises a minimum load circuit configured to maintain a minimum load for the PoE scheme, 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. ### Claim 2 (depends on 1) The automation system of claim 1, wherein the minimum load circuit is configured to maintain the minimum load only when the input and/or output device is not powered by power sourcing equipment via an Ethernet connection. ### Claim 3 (depends on 1) The automation system of claim 1, wherein the minimum load circuit comprises a single resistor configured to maintain the minimum load. ### Claim 4 (depends on 1) The automation system of claim 1, wherein the minimum load circuit comprises a voltage regulator and a resistor to maintain the minimum load. ### Claim 5 (depends on 1) The automation system of claim 1, wherein the comparator circuit comprises an operational amplifier, a field-effect transistor, and a resistor to maintain the minimum load. ### Claim 6 (depends on 1) The automation system of claim 1, wherein the minimum load comprises a nominal 10 mA current. ### Claim 7 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. ### Claim 8 (depends on 7) The automation system of claim 7, wherein the PoE circuit comprises a classification circuit configured to enable classification of the input/output device based on the power required by the input/output device. ### Claim 9 (depends on 7) The automation system of claim 7, wherein the minimum load circuit comprises a single resistor configured to maintain the minimum load. ### Claim 10 (depends on 7) The automation system of claim 7, wherein the minimum load circuit comprises a voltage regulator and a resistor to maintain the minimum load. ### Claim 11 (depends on 7) The automation system of claim 7, wherein the comparator circuit comprises an operational amplifier, a field-effect transistor, and a resistor to maintain the minimum load. ### Claim 12 (depends on 7) The automation system of claim 7, comprising a DC/DC converter. ### Claim 13 (depends on 12) The automation system of claim 12, comprising an auxiliary power source connector configured to enable connection of an auxiliary power source on a power input pathway between the PoE circuit and the DC/DC converter. ### Claim 14 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. ### Claim 15 (depends on 14) The method of claim 14, comprising maintaining a minimum load on a PoE connection in the automation input/output device to enable detection of the automation input/output device by the PoE source. ### Claim 16 (depends on 15) The method of claim 15, wherein the minimum load circuit comprises a single resistor configured to maintain the minimum load. ### Claim 17 (depends on 15) The method of claim 15, wherein the minimum load circuit comprises a voltage regulator and a resistor to maintain the minimum load. ### Claim 18 (depends on 14) The method of claim 14, comprising switching to providing power to the input/output device from the PoE source when the PoE source supplies more power than the auxiliary power source. ### Claim 19 (depends on 18) The method of claim 18, comprising providing an auxiliary power connection coupled to the power input pathway after the minimum load circuit. ### Claim 20 (depends on 19) The method of claim 19, comprising providing the auxiliary power connection to the power input pathway after the minimum load circuit via the second DC/DC converter.