US 5,993,039 A · Power-loss interlocking interface method and apparatus

Abstract

A latching interface is provided between a machine and a monitoring or control system for the machine to latch the machine in a mode that is safe for the machine and for operating personnel upon power loss. The interface includes one or more latching relay switches, connected into one or more input signal circuits, that may be selectively set and reset by an interface microprocessor to actuate or deactuate the machine from performing certain functions. The interface microprocessor is programmable to set or reset the latching relay switches in response to a signal from a power loss sensor indicating that power to a monitor/controller device, that monitors and controls the functions of the machine, has been interrupted. The interface system further includes a power feed circuit to provide a back-up power supply to power the interface microprocessor during setting and resetting of the latching relay switches to the safe mode upon loss of normal power. Alternately, a solid state switch in series with an additional latching relay switch is connected into the input signal circuit in parallel with one or more of the latching relay switches. During normal operations, the interface microprocessor may operate these solid state switches in response to signals from the monitor/controller to control normal operating modes or functions of the machine. Upon power loss, the interface microprocessor opens the latching relay switch in series with each solid state switch and operates the parallel latching relay switch to place and keep the machine in a safe operating mode.

Claims9

Dependent claims

For a machine that is powered by a primary power source and that requires repetitious input signals from a monitor/controller system that is also powered by the primary power source via a primary power circuit to continue performing functions for which the machine is designed, and in which the machine has an input signal circuit that requires on and off switching of electricity in the input signal circuit to actuate the machine to perform certain functions or to deactuate the machine from performing said functions, an interface system comprising:

a latching relay switch positioned in said input signal circuit, which latching relay switch has the capability to close the input signal circuit of the machine in response to a close signal and the capability to open the input signal circuit of the machine in response to an open signal;
an interface microprocessor that is programmed to generate whichever close signal or open signal that is required to set the latching relay switch in a state that, in response to a power-fail signal, deactuates and prevents the machine from performing said functions regardless of whether the machine is or is not powered by said primary power source;
a power-fail detector connected to the primary power circuit, which power-fail detector has a capability to detect when electric power from the primary power source is interrupted or fails and in response to generate the power-fail signal;
an isolated power supply connected to the interface microprocessor, but not to the machine, said isolated power supply having sufficient back-up electric power to enable the interface microprocessor, in response to said power-fail signal, to generate the close signal or the open signal that sets or resets the latching relay switch in a state that deactuates and prevents the machine from performing said functions.

1 more element

A method of controlling a machine that is powered by a primary power source and has an input signal circuit which actuates the machine to perform a function or that deactuates the machine from performing the function, depending on whether the input signal circuit is opened or closed, comprising the steps of:

connecting a first latching relay switch into said input signal circuit of the machine such that said first latching relay switch in a closed state closes said input signal circuit of the machine and that said first latching relay switch in an open state opens said input signal circuit of the machine;
connecting an interface microprocessor to said first latching relay switch in such a manner that said interface microprocessor is responsive to an actuate signal from a controller that is also powered by the primary power source to assert whichever open state or closed state of the first latching relay switch results in such actuation and is also responsive to a power-fail signal to assert whichever open state or closed state of the first latching relay switch results in deactuating and preventing the machine from performing said function regardless of whether the machine is or is not powered by said primary power source;
and
monitoring the primary power source in a manner that detects any interruption or failure of the primary power source to the controller and generating the power-fail signal in response to detection of such an interruption or failure of the primary power source to the controller.

1 more element

Dependencies are inferred from the claim text.

Power-loss interlocking interface method and apparatus

Life of this patent

Power-loss interlocking interface method and apparatus

Life of this patent

Abstract

Claims9