Condition control system with safety feedback means
AssigneeHoneywell Inc.
InventorsRobert A. Black, Gary A. Peterson
Life of this patent
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Abstract
A condition control system in the form of a fuel burner control means is disclosed. A group of relays and their associated contacts are used to control the burner means. The status of the relays and their contacts are continuously checked by a control logic means by having the voltage on key relay output contacts fed into the control logic means through isolated signal transmission means. All of the relays are capable of being deenergized in the event of the need for safety shut down as determined by the control logic means.
Claims18
A condition control system having a plurality of output relays adapted to control load means with said load means including at least one critical load and wherein said output relays are monitored to insure the safe operation of said load means, including;
- control logic means having a plurality of output relays with said control logic means adapted to operate said load means in response to condition responsive means;
- said output relays each having at least one pair of relay contacts;
- said output relay contacts connected wherein a pair of contacts from at least two relays electrically are connected in a series energizing circuit to said critical load to insure that electrical failure of one of said pairs of contacts will not preclude the deenergization of said critical load upon said relays being operated by said control logic means to open said series circuit;
- isolated signal transmission means connected to said relay contacts to supply signals to said control logic means as to the state of said relay contacts;
- and solid state switch means controlled by said control logic means and connected to all of said relays to operably control power to all of said relays;
- said solid state switch means responding to said control logic means to remove power from all of said control logic means to remove power from all of said relays when said control logic means discerns a relay contact failure in response to signals from said isolated signal transmission means.
A condition control system having a plurality of output relays adapted to control load means wherein said output relays are monitored to insure the safe operation of said load means, including;
- control logic means having a plurality of output relays with said control logic means adapted to operate said load means in response to condition responsive means by selectively operating said relays in a predetermined sequence;
- said output relays each having at least one pair of relay contacts;
- said output relay contacts selectively connecting said load means to a source of power upon said relays being operated by said control logic means to operably energize said load means;
- isolated signal transmission means connected to said relay contacts to supply signals to said control logic means as to the state of said relay contacts;
- said control logic means selectively operating said plurality of output relays and responding to said isolated signal transmission means;
- and solid state switch means controlled by said control logic means and connected to all of said relays to operably control power to all of said relays;
- said solid state switch means responding to said control logic means to remove power from all of said relays when said control logic means discerns a relay contact failure in response to signals from said isolated signal transmission means.
Dependencies are inferred from the claim text.