US 5,329,273 AGranted

System controller and remote fault annunciator with cooperative storage, sharing, and presentation of fault data

AssigneeHoneywell Inc.

InventorPaul B. Patton

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Abstract

An annunciator for the conduction status of individual switches wired into a series circuit records this status as status history at regular intervals in a memory. The status history is preferably recorded as individual entries having the identification number of an open switch along with a time stamp specifying the length of time which that switch has been open. The current entry is recorded in the memory and a new entry started each time the switch for which an entry in the memory is being created closes or a switch currently receiving power opens. A controller separate from the annunciator generates a request signal and provides a request time value to the annunciator specifying the time which has elapsed since the request condition was detected. The annunciator uses the request time value to determine the probable switch conduction status at the time of the request.

Claims17

Dependent claims

A status recorder for recording a status history of a plurality of interlock switches each having a pair of contacts, said contacts connected by a plurality of conductors to form a series circuit of interlock switches in a preselected sequence, said series circuit for connection to pass current from a power source to a load and having a first out status value representing the conductive status of the switches, and including a plurality of voltage sensors each associated with an interlock switch, and each voltage sensor connected to a conductor connected to the interlock switch with which the voltage sensor is associated and providing a status signal having a first state responsive to presence of power voltage on the conductor to which it is connected and a second state otherwise, and further comprising

a) signal selector means receiving the status signals for providing a selector signal encoding the first out status value of the interlock switches;
b) a first out register receiving the selector signal and a status change signal, recording as its contents information encoded in the selector signal responsive to the status change signal, and providing a first out register signal encoding the contents of the first out register,
c) an oscillator issuing a clock signal having level changes at preset intervals;
d) a counter storing a time stamp value, receiving the clock signal, changing the time stamp value by a predetermined amount responsive to each level change in the clock signal, and providing a time stamp signal encoding the time stamp value;
e) status change sensing means receiving the selector signal and the first out register signal for comparing the information encoded in the selector signal and the first out register signal, and responsive to disagreement therebetween, providing the status change signal;
and
f) a memory receiving the status change signal, the first out register signal, and the time stamp signal, for sequentially recording responsive to each status change signal, a history entry comprising the information encoded in the first out register signal and the time stamp value encoded in the time stamp signal, and for providing a history signal encoding recorded history entries.

4 more elements

A method for recording in a microprocessor memory having a plurality of addressable storage locations, a status history of a plurality of interlock switches, each interlock switch having a pair of contacts, said contacts connected by a plurality of conductors to form a series circuit of interlock switches in a preselected sequence, said series circuit for connection to pass current from a power source to a load, and having a first out status value representing the conductive status of at least a selected plurality of the switches, said series circuit further including a plurality of voltage sensors each associated with an interlock switch, and each voltage sensor connected to a conductor connected to the interlock switch with which the voltage sensor is associated and providing a status signal having a first state responsive to presence of power voltage on the conductor to which it is connected and a second state otherwise, said method comprising in the microprocessor, the steps of

a) recording in the microprocessor memory location specified by an index recorded in a memory index location, the information currently encoded in at least one selected status signal;
b) issuing a clock signal having level changes at preset intervals;
c) responsive to each level change in the clock signal, incrementing a time stamp value recorded in the memory at the location specified by the index;
and
d) responsive to each level change in the clock signal, comparing the information currently encoded in each selected status signal and the status signal information recorded in the memory location specified by the index, and responsive to disagreement therebetween, incrementing the index, and then recording the information currently encoded in each selected status signal in the microprocessor memory location specified by the index and setting to a preselected value the time stamp value recorded in the memory at the location specified by the index.

2 more elements

Dependencies are inferred from the claim text.