Low power self-limiting input circuit
AssigneeRockwell Automation Technologies, Inc.
InventorsJoseph Vazach, Terry L. Deloria
Life of this patent
Estimating the term…
Abstract
An input circuit for an input module having a plurality of inputs is disclosed. Each input circuit has a reduced number of components, providing for an increased number of inputs within an input module of comparable size to prior art input modules. Alternately, the input module may have a like number of inputs in a reduced size in comparison to prior art input modules. The reduced number of components similarly reduces the power dissipated by each input circuit.
Claims9
An input circuit for an industrial controller, comprising:
- a first terminal and a second terminal configured to receive a voltage potential, wherein the first terminal is configured to be a positive terminal for the voltage potential with respect to the second terminal;
- a zener diode having a cathode and an anode, the cathode electrically connected to the first terminal;
- a current limit diode having a cathode and an anode, the anode of the current limit diode electrically connected to the anode of the zener diode;
- and
- an opto-coupler having a light emitter and a photosensor, the light emitter electrically connected in series between the cathode of the current limit diode and the second terminal.
An input circuit for an input module in an industrial controller, comprising:
- an input configured to receive a range of direct current (DC) voltages;
- a zener diode electrically connected to the input to operate in a breakdown region when the DC voltage is applied to the input;
- a current limit diode electrically connected in series with the zener diode to operate in a current limiting mode when the DC voltage is applied to the input;
- and
- an opto-coupler having an input and an optically isolated output wherein the input is electrically connected to the series-connected zener diode and current limit diode and the optically isolated output generates a signal that corresponds to a logical true when the DC voltage is applied to the input and a logical false when the DC voltage is removed from the input.
Dependencies are inferred from the claim text.