System and method for controlling a latching relay failsafe
AssigneeParker-Hannifin Corporation
InventorsZachary R. WRIGHT, Ted W. SUNDERLAND
Life of this patent
Estimating the term…
Abstract
A control circuit includes a latching relay, a power loss activation circuit, and a watchdog circuit. A microcontrol unit (MCU) communicates with the watchdog circuit in a normal operation of the control circuit. As an action of a failsafe precaution in the event of a main power loss or a component failure, the MCU stops communicating with the watchdog circuit, at which point the watchdog circuit instructs the power loss activation circuit to continue operation of the control circuit. The control circuit further operates to implement mitigation operations in the event of a main power loss or component failure.
Claims22
A control circuit, comprising:
- a relay including at least a first coil terminal and a second coil terminal;
- a first monitoring circuit having a first node coupled to a power supply input configured to activate the first coil terminal in the event of a power loss;
- a microcontrol unit (MCU), wherein, under a normal operation, the MCU operates to constantly reinforce a state of the relay;
- and
- a watchdog circuit communicative with the MCU, wherein the watchdog circuit is configured to activate the first coil terminal in the event that the MCU stops communication with the watchdog circuit.
A method of driving a relay, comprising:
- monitoring an operation of a control circuit, wherein a microcontrol unit (MCU) communicates directly with a watchdog circuit, wherein, under a normal operation, the MCU operates to constantly reinforce a state of the relay;
- and activating the watchdog circuit in the event that communication of the MCU with the watchdog circuit ceases, wherein the watchdog circuit is configured to activate a first coil terminal of the relay by way of a first relay control circuit to control operation of a relay.
Dependencies are inferred from the claim text.