Patent ID: 6683432
Filing Date: 2004-01-27
Classification: G05B

Abstract:
An electronic control system for machinery comprising:a motion control system comprising means to effect controlled motion of each axis of said machinery, wherein said motion control system carries out the task of said machinery; an emergency-stop circuit comprising means for controlling the flow of bulk power, wherein presence of said flow of bulk power empowers said motion control system to effect controlled motion for said each axis, wherein absence of said flow of bulk power prevents uncontrolled motion of said each axis, wherein said means for controlling said flow of bulk power is responsive to the command of an operator; at least one hazard sensor, wherein each hazard sensor provides at least one hazard sensor value; and at least one safety circuit, wherein said safety circuit prevents hazardous situations, wherein said safety circuit receives from at least one of said at least one hazard sensor at least one of said at least one hazard sensor value; wherein said safety circuit further comprises a risk assessment means that generates at least one hazard assessment, each of which is a sensed degree of hazard present for at least one of said at least one of said at least one hazard sensor value, wherein said risk assessment means further determines the most severe of said at least one hazard assessment which sets the hazard severity level for said safety circuit, whereby said hazard severity level is assigned one of at least three severity levels (a) hazard is not present, (b) hazard is present but not dangerous, or (c) hazard is dangerous; wherein said safety circuit further comprises (d) a first control means to variably restrict operation of said motion control system, (e) a second control means to stop or keep stopped said flow of bulk power by way of said emergency-stop circuit, wherein said second control means when activated overrides the command of an operator to start said flow of bulk power, and (f) a first sensing means to determine whether said bulk power flows or whether said emergency-stop circuit is energized, wherein said safety circuit further controls operation of said machinery in a plurality of operating states, wherein said operating states comprise unrestricted operation (ACTIVE), partially restricted operation (HALT), and totally restricted operation (KILLED), wherein said states qualify operation so that (g) said ACTIVE state does not restrict operation, (h) said HALT state restricts motion for each affected axis through said motion control system wherein said first control means is used, and (i) said KILLED state stops motion for each affected axis through said motion control system wherein said first control means is used and stops said flow of bulk power to said machinery through said emergency-stop circuit wherein said second control means is used and keeps stopped said flow of bulk power wherein said second control means is continuously used as long as said hazard severity level is hazard is dangerous, wherein said safety circuit further comprises a state machine means to maintain state or change state so that said safety circuit maintains (j) said KILLED state when said hazard severity level is hazard is dangerous, and otherwise transitions to (k) said KILLED state when power is first applied to logic of said electronic control system or when said first sensing means to sense said flow of bulk power determines said bulk power has stopped flowing or when said hazard severity level is hazard is dangerous, or (l) said HALT state when said hazard severity level is hazard is present but not dangerous and said bulk power flows as sensed by said first sensing means, or (m) said ACTIVE state when said hazard severity level is hazard is not present and said bulk power flows as sensed by said first sensing means.