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US 4,395,638 AGranted
Self-checking flame failure control
AssigneeElectronics Corporation of America
InventorPhillip J. Cade
Life of this patent
Estimating the term…
Abstract
This invention relates to control circuits of the type which continuously monitor their own performance so as to be self-checking, i.e., to produce a response whenever the system shows the absence of a condition being monitored or a change therein and also produces a response if the control system itself should become inoperative or otherwise malfunction.
Claims6
A solid state self-checking system comprising
- first and second sensor means for sensing the same event and generating signals which are comparable upon sensing the same event;
- signal comparing means responsive to said signals from said first and second sensor means for generating a negation response in the absence of comparable signals and responsive to the presence of said comparable signals for generating a comparison response;
- switching means coupled to the output of said signal comparing means for alternately interrupting comparison of said signals in said comparison means in response to said comparison response and restoring comparison in response to said negation response;
- and
- utilization means operable in response to the alternating operation of said switching means.
2 more elements
A fail-safe self-checking system comprising:
- a pair of sensors each adapted to sense the affirmation or negation of the same event and produce comparable signals representative of the state of the event;
- a signal comparator coupled to said sensors for comparing said signals from said sensors;
- means responsive to the output of said comparator representing the affirmation comparison of both said signals applied to said comparator for interrupting one of said signals, said means terminating said interrupting upon a failure to maintain said affirmation comparison output;
- and
- means responsive to the sustained alternation of presence and absence of comparison output for maintaining said system energized, said means deenergizing said system upon cessation of said alternation.
2 more elements
Dependencies are inferred from the claim text.