WO2004012017A2 - Terme de transfert sans bosse (bumpless) pour systeme de controle - Google Patents

Terme de transfert sans bosse (bumpless) pour systeme de controle Download PDF

Info

Publication number
WO2004012017A2
WO2004012017A2 PCT/SG2002/000161 SG0200161W WO2004012017A2 WO 2004012017 A2 WO2004012017 A2 WO 2004012017A2 SG 0200161 W SG0200161 W SG 0200161W WO 2004012017 A2 WO2004012017 A2 WO 2004012017A2
Authority
WO
WIPO (PCT)
Prior art keywords
term
control
bump
transfer
controller
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SG2002/000161
Other languages
English (en)
Other versions
WO2004012017A3 (fr
Inventor
Manuel Jesubatham Pakianathan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to AU2002320005A priority Critical patent/AU2002320005A1/en
Publication of WO2004012017A2 publication Critical patent/WO2004012017A2/fr
Anticipated expiration legal-status Critical
Publication of WO2004012017A3 publication Critical patent/WO2004012017A3/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B7/00—Arrangements for obtaining smooth engagement or disengagement of automatic control
    • G05B7/02—Arrangements for obtaining smooth engagement or disengagement of automatic control electric

Definitions

  • an error signal is derived in response to a measurement of a parameter it is desired to control.
  • An automatic control signal is then derived from the error signal by a controller and used to control some aspect of the system to compensate the error.
  • this control signal is made to be proportional to the error signal.
  • components of the control signal are also produced which are the first order derivative or integral of the error signal. Controllers which employ these components are usually called proportional plus derivative (P+D) or proportional plus integral (P+I) controllers. It is also possible to have a so-called three term controller, i.e. proportional plus integral plus derivative (P+I+D or PID) controller.
  • the derivative component is used if it is desired to reduce the lag (increase the response time of the system). Integral control is used primarily to eliminate offset, i.e. failure of the controlled parameter to return to exactly the required level (set point).
  • the additional term 'BT(t)' in the control equation has a magnitude as well as what may be called as the bleed rate. This bleed rate is given in minutes or in seconds, and it should be set, like integral and derivative action rates by the process control engineer.
  • the initial value of BT(t)' depends on the manual value of the output before the bump- less transfer to automatic control. Hence, the magnitude of 'BT(t)' is internally set, and is not externally set as its bleed rate.
  • P+D controllers are rarely used, as whenever derivative action is used the integral term is invariably used. Further, the transfer from manual to automatic control is usually done in the steady state. Hence, there will be no difference in the error at the nth sampling interval and the (n-l)th sampling interval, and so the derivative action term will be zero. If this is not so, it is still advisable to neglect the term as it is small, and at this stage it can be quite unreliable. However, if it is not ignored, the initial value of 'BTn for a direct acting controller is as follows:
  • Figure 1 shows five graphs.
  • Graph A shows the level input versus the controller output for a direct acting controller with a gain of 1 and a bias value of 50%.
  • Graph B shows a reverse acting controller with a gain of 1 and a bias value of 50%.
  • Graph C shows a direct acting controller with a gain of 1 but with a bias value of 75%. From graph C it can be easily seen why when the bias value of a controller is set at other than the mid range value of 50%, it will result in a lopsided control system that is quite unacceptable.
  • Graph D shows another lopsided control system if the bias value was set at 25%, when the level was at 50%.
  • graph E shows a proportional control with a gain of 2, and a bias of 50%.
  • a controller with a gain of 2 is also known as having a 50% proportional band (PB), while a gain of 1 is known as 100% PB.
  • PB 50% proportional band
  • FIG. 2 shows a level control system at the time of transfer from manual to automatic control.
  • Figure 3 shows the same system when the value of BT(t) is zero, by which time the level in the tank has risen to 75%, assuming the flow into the tank has remained the same.
  • the system consists of a tank (1) containing a liquid (2). It is filled from an uncontrolled liquid conduit (3), and it is desired to maintain the liquid between 0% and 100%.
  • a displacer type of level sensing element (4), a level transmitter (5), and a DCS controller (6) are connected to a current to pneumatic positioner of a control valve (7).
  • the controller in this case, is made to be a direct acting proportional only controller with a gain of 1 and a set-point of 50%.
  • Such a controller will ensure that the system is controlled between the prescribed limits, in this case between 0% and 100%.
  • the control valve chosen is such that it opens more as the controller output OP(t)' increases.
  • the level in the tank was 50%, matching the set-point, and the manual output was 75%, for a bump-less transfer to take place the output of the controller has also to be 75%.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Feedback Control In General (AREA)

Abstract

Sachant que chaque transfert de système de contrôle de processus, de manuel en automatique, doit généralement s'effectuer sans bosse (bumpless), c'est-à-dire sans changement en sortie, l'invention concerne un procédé visant à assurer ce transfert pour un organe de contrôle d'action proportionnelle sans action par intégration. Jusqu'à présent, aucun moyen adapté ne permettait d'effectuer un tel transfert pour ce type d'organe de contrôle. Selon le procédé décrit, on utilise un terme additionnel, appelé pour les besoins de l'invention terme de transfert sans bosse (Bumpless Transfer) 'BT(t)', destiné à être incorporé à l'algorithme de contrôle. Il s'agit d'un terme à brève durée seulement, intervenant simplement pour assurer le transfert sans bosse. Ledit terme comprend deux éléments, à savoir 1) valeur 2) temps de descente. Le temps de descente est le temps requis pour la descente du terme 'BT(t)' de sa valeur initiale à zéro. La valeur initiale du terme 'BT(t)' dépend de la valeur de la sortie manuelle de l'organe de contrôle avant le transfert de manuel en automatique, et elle est fixée en interne par l'ordinateur. Ce temps de descente détermine la durée de l'activité du terme une fois le transfert effectué, et il est établi par l'ingénieur du contrôle de processus. Aux fins de l'invention, il semble que l'on n'ait encore jamais utilisé de tel terme pour le transfert sans bosse appliqué à l'organe de contrôle considéré ou à toute autre forme de contrôle. En l'absence de ce genre de terme, bien des concepteurs de systèmes de contrôle modifient la valeur de biais pour les besoins du transfert sans bosse, mais cela donne un système de contrôle déséquilibré totalement inadapté aux organes de contrôle de type proportionnel sans action par intégration. La valeur de biais doit être maintenue à 50 % si l'on veut disposer d'un système de contrôle performant et fiable. A cet effet, on trouvera dans la description 1) une introduction qui résume les antécédents et l'état de la technique en matière de contrôle, et 2) une présentation du procédé et de sa mise en oeuvre. On trouvera également des équations mathématiques sous forme analogue et discrète qui définissent les organes de contrôle. Ces équations montrent qu'il est nécessaire d'utiliser le terme de transfert considéré dans un organe de contrôle de type proportionnel sans action par intégration, et elles montrent pourquoi l'utilisation d'un tel terme n'est pas nécessaire dans un organe de contrôle de type proportionnel à action par intégration. Pour illustrer le fonctionnement du système et les inconvénients pouvant survenir si l'on n'utilise pas le terme de transfert en question, une application de contrôle de niveau à contrôle proportionnel uniquement est prise en considération durant le transfert de manuel à automatique. Les figures 1, 2, et 3 illustrent d'ailleurs les difficultés correspondantes et leur résolution pour l'utilisation du terme de transfert 'BT(t)' dans un organe de contrôle à contrôle proportionnel uniquement, en cours de transfert de manuel à automatique.
PCT/SG2002/000161 2002-07-08 2002-07-17 Terme de transfert sans bosse (bumpless) pour systeme de controle Ceased WO2004012017A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002320005A AU2002320005A1 (en) 2002-07-08 2002-07-17 Novel bump-less transfer term for control. system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SG200204078-0 2002-07-08
SG200204078 2002-07-08

Publications (2)

Publication Number Publication Date
WO2004012017A2 true WO2004012017A2 (fr) 2004-02-05
WO2004012017A3 WO2004012017A3 (fr) 2006-04-20

Family

ID=31185901

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SG2002/000161 Ceased WO2004012017A2 (fr) 2002-07-08 2002-07-17 Terme de transfert sans bosse (bumpless) pour systeme de controle

Country Status (2)

Country Link
AU (1) AU2002320005A1 (fr)
WO (1) WO2004012017A2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2470906A (en) * 2009-06-08 2010-12-15 Ove Arup & Partners Internat Ltd Rainwater harvesting system
US9651923B2 (en) * 2014-06-27 2017-05-16 Manuel Jesubatham Pakianathan Bump-less transfer term for proportional action controllers that eschew the integral action term

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4035620A (en) * 1975-08-25 1977-07-12 Phillips Petroleum Company Bumpless control transfer
US5867384A (en) * 1997-07-08 1999-02-02 Johnson Services Company Feedback controller

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2470906A (en) * 2009-06-08 2010-12-15 Ove Arup & Partners Internat Ltd Rainwater harvesting system
GB2470906B (en) * 2009-06-08 2014-04-16 Ove Arup & Partners Internat Ltd Rainwater harvesting system
US9651923B2 (en) * 2014-06-27 2017-05-16 Manuel Jesubatham Pakianathan Bump-less transfer term for proportional action controllers that eschew the integral action term

Also Published As

Publication number Publication date
WO2004012017A3 (fr) 2006-04-20
AU2002320005A1 (en) 2004-02-16
AU2002320005A8 (en) 2004-02-16

Similar Documents

Publication Publication Date Title
EP1321836B1 (fr) Regulateur, regulateur de temperature et regulateur de chaleur
CA1168332A (fr) Controleur molaire de debit gazeux
KR910003240A (ko) 터빈 제어의 컴퓨터 보조 운전
JP2013525870A (ja) 一貫した応答を実現する、オンツールおよびオンサイトｍｆｃ最適化方法およびシステム
WO2004012017A2 (fr) Terme de transfert sans bosse (bumpless) pour systeme de controle
CA2297289C (fr) Procede a gain non lineaire pour la prevention de l'emballement des regulateurs pid
US9651923B2 (en) Bump-less transfer term for proportional action controllers that eschew the integral action term
WO2014017978A1 (fr) Nouveau terme de transfert sans bosse pour des dispositifs de contrôle d'action proportionnelle qui évitent le terme d'action par intégration
EP0775339B1 (fr) Transducteur courant-pression a filtre d'entree pouvant etre selectionne et regle
JPS6215435B2 (fr)
US20240248496A1 (en) Fluid control device, fluid control system, fluid control device program, and fluid control method
JP2020187522A (ja) 制御選択調節装置
JPS58140807A (ja) 積分リミツタ自動調節機構付き制御装置
CN111022730B (zh) 一种处理调节阀门结晶堵塞的系统、方法和存储介质
JPH02183815A (ja) 給水流量制御装置
JPS57166613A (en) Plant flow rate controller
JPH02304604A (ja) 流量制御装置
JPH05134705A (ja) 補完フイードバツク制御装置
JPH09282001A (ja) 手動切替え機能を有する制御装置
JPS61237104A (ja) プロセス制御方法
SU1372463A1 (ru) Способ автоматического регулировани перетока мощности между двум част ми энергосистемы
JPS597965B2 (ja) 電気ガバナ
SU1246051A1 (ru) Пневматический пропорционально-интегральный регул тор
JPS5914803Y2 (ja) 弁制御装置
JP2811935B2 (ja) 湯水混合制御装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP