# US 7,608,169 B2 · Apparatus and method for break recovery in a paper machine or other system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,169 B2 - Document ID: US7608169B2 - Status: Granted - Kind: B2 - Application number: 11/501,576 - Filed: 2006-08-09 - Published: 2008-02-14 - Granted: 2009-10-27 - Earliest claimed: 2006-08-09 - Assignees: Honeywell ASCa Inc. - Inventors: Johan U. Backstrom; Gregory E. Stewart - Web page: https://patentgrep.com/patent/US7608169B2 ## CPC - D21F 7/06: Indicating or regulating the thickness of the layer; Signal devices - D21G 9/0036: {controlling the press or drying section} - D21F: PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON - D21G: CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H) ## Abstract A method includes determining one or more setpoint changes for one or more actuators in a process control system. Determining the one or more setpoint changes includes making larger or more frequent setpoint changes when operating in a first mode and making smaller or less frequent setpoint changes when operating in a second mode. The method also includes outputting the one or more setpoint changes to the one or more actuators. The method could further include entering the first mode after a paper sheet has broken and been rethreaded through a paper machine. The method could also include entering the second mode (i) after a specified amount of time has elapsed since entering the first mode or (ii) after the first mode has been entered and a caliper profile of the paper sheet is within a specified threshold of a desired caliper profile. ## Claims ### Claim 1 A method, comprising: determining one or more setpoint changes for one or more actuators in a process control system, wherein determining the one or more setpoint changes comprises: making larger or more frequent setpoint changes when operating in a first mode; and making smaller or less frequent setpoint changes when operating in a second mode; and outputting the one or more setpoint changes to the one or more actuators; wherein making the smaller or less frequent setpoint changes comprises determining the smaller or less frequent setpoint changes using control logic; and wherein making the larger or more frequent setpoint changes comprises applying a gain to the smaller or less frequent setpoint changes determined by the control logic. ### Claim 2 (depends on 1) The method of claim 1, wherein the process control system comprises a paper machine operable to produce a paper sheet; and further comprising entering the first mode after the paper sheet has broken and been rethreaded through the paper machine. ### Claim 3 (depends on 2) The method of claim 2, further comprising entering the second mode after a specified amount of time has elapsed since entering the first mode. ### Claim 4 (depends on 2) The method of claim 2, wherein the one or more actuators comprise one or more induction heating actuators operable to adjust a caliper profile of the paper sheet; and further comprising entering the second mode after the first mode has been entered and the caliper profile of the paper sheet is within a specified threshold of a desired caliper profile. ### Claim 5 (depends on 1) The method of claim 1, further comprising: providing a graphical user interface to a user; and receiving from the user, using the graphical user interface, at least one of: information specifying whether a transition from the first mode to the second mode occurs manually or automatically; information specifying a length of time required before automatically switching from the first mode to the second mode; and information indicating when the transition from the first mode to the second mode manually occurs. ### Claim 6 (depends on 1) The method of claim 1, wherein outputting the one or more setpoint changes comprises processing the one or more setpoint changes to provide anti-windup protection and outputting the one or more processed setpoint changes to the one or more actuators. ### Claim 7 (depends on 6) The method of claim 6, further comprising: receiving information from a user specifying a level of anti-windup protection. ### Claim 8 An apparatus, comprising: a control module operable to determine one or more setpoint changes for one or more actuators in a process control system, the control module operable to determine the one or more setpoint changes by: making larger or more frequent setpoint changes when operating in a first mode; and making smaller or less frequent setpoint changes when operating in a second mode; and an interface operable to output the one or more setpoint changes to the one or more actuators; wherein the control module comprises: control logic operable to determine the smaller or less frequent setpoint changes; and a gain unit operable to apply again to the smaller or less frequent setpoint changes to produce the larger or more frequent setpoint changes. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein: the process control system comprises a paper machine operable to produce a paper sheet; and the control module is further operable to enter the first mode after the paper sheet has broken and been rethreaded through the paper machine. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the control module is further operable to enter the second mode after a specified amount of time has elapsed since entering the first mode. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein: the one or more actuators comprise one or more induction heating actuators operable to adjust a caliper profile of the paper sheet; and the control module is further operable to enter the second mode after the first mode has been entered and the caliper profile of the paper sheet is within a specified threshold of a desired caliper profile. ### Claim 12 (depends on 8) The apparatus of claim 8, further comprising a graphical user interface operable to receive from a user at least one of: information specifying whether a transition from the first mode to the second mode occurs manually or automatically; information specifying a length of time required before automatically switching from the first mode to the second mode; and information indicating when the transition from the first mode to the second mode manually occurs. ### Claim 13 (depends on 8) The apparatus of claim 8, further comprising an anti-windup unit operable to process the one or more setpoint changes to provide anti-windup protection; and wherein the interface is operable to output the one or more processed setpoint changes to the one or more actuators. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein a level of anti-windup protection is specified by a user. ### Claim 15 (depends on 8) The apparatus of claim 8, wherein the control module is executed by a controller in the process control system. ### Claim 16 A computer readable medium embodying a computer program, the computer program comprising: computer readable program code for determining one or more setpoint changes for one or more actuators in a process control system, wherein the computer readable program code for determining the one or more setpoint changes comprises: computer readable program code for making larger or more frequent setpoint changes when operating in a first mode; and computer readable program code for making smaller or less frequent setpoint changes when operating in a second mode; and computer readable program code for outputting the one or more setpoint changes to the one or more actuators; wherein the computer readable program code for making the smaller or less frequent setpoint changes implements control logic for determining the smaller or less frequent setpoint changes; and wherein the computer readable program code for making the larger or more frequent setpoint changes comprises computer readable program code for applying a gain to the smaller or less frequent setpoint changes. ### Claim 17 (depends on 16) The computer readable medium of claim 16, wherein the process control system comprises a paper machine operable to produce a paper sheet; and further comprising computer readable program code for entering the first mode after the paper sheet has broken and been rethreaded through the paper machine. ### Claim 18 (depends on 17) The computer readable medium of claim 17, further comprising computer readable program code for entering the second mode after a specified amount of time has elapsed since entering the first mode. ### Claim 19 (depends on 17) The computer readable medium of claim 17, wherein the one or more actuators comprise one or more induction heating actuators operable to adjust a caliper profile of the paper sheet; and further comprising computer readable program code for entering the second mode after the first mode has been entered and the caliper profile of the paper sheet is within a specified threshold of a desired caliper profile. ### Claim 20 A system, comprising: a paper machine operable to produce a paper sheet, the paper machine comprising a plurality of actuators; and a controller operable to determine one or more setpoint changes for one or more of the actuators, the controller operable to determine the one or more setpoint changes by: making larger or more frequent setpoint changes when operating in a first mode; and making smaller or less frequent setpoint changes when operating in a second mode; wherein the controller: control logic operable to determine the smaller or less frequent setpoint changes; and a gain unit operable to apply a gain to the smaller or less frequent setpoint changes to produce the larger or more frequent setpoint changes.