1、Manual on Installation of RefineryInstruments and Control SystemswE至孕OD上f时a、Part l-Process Instrumentation and ControlSection 5-Controllers and Control SystemsAPI RECOMMENDED PRACTICE 550FOURTH EDITION,JULY 1985American Petroleum Institute1220 L Street.NorthwestWashington,D.C.20005CONTENTSSECTION 5-
2、CONTROLLERS AND CONTROL SYSTEMSPAGE5.1Sc0pe,5.2 Referenced Publications.,.,.-5.3 Terms and Definitions.5.4Single Loop Controllers.25.5 Distributed Control Systems.,。.25.5.I Types of Distributed Control Systems.455.5.2Flexibility of Distributed Control Systems5.5.3 Geographic Distribution.65.5.4 Algo
3、rithms for Control and Computation.65.5.50 perator Interface.。65.5.6 Bus Structure and Protocol.75.5.7 Diagn0 stics5.5.8 Reliability.5.5.9 Power Supply Requirements.105.5.10 Site Planning.105.6 Programmable Controllers.105.7 Control Actions.5.7.1 On/Off Control.5.7.2 Proportional Control.115.7.3 Pro
4、portional Plus Integral Control.25.7.4 Proportional Plus Derivative Control.135.7.5Proportional Plus Integral Plus Derivative Control.35.7.6 Nonlinear Control.135.8 Typical Control Actions and Settings for Common Applications.14145.8.1Fow5.8.2 Pressure.I45.8.3 Temperature.145.8.4 Level45.9 Tuning Co
5、ntrollers45.10 Other Control Applications.155.10.I Caseade Control.155.10.2 Ratio Control.155.10.3 Feedforward Control.55.10.4 Override Control.55.10.5 Adaptive and Self-Tuning Control.195.10.6 Supplementary Functions.205.10.7 Controllers Interfacing with Computers.205.l0.8 Digital Blending Systems.
6、-.215.11 Locating Single Loop Controllers.235.11.I Factors Affecting Controller Location35.11.2 Transmission Lags.235.11.3 Considerations in Mimimizing Pneumatic Lag.245.11.4 Centralizing Control Stations.245.11.5 Locally Mounted Pneumatic Controllers.245.11.6 Special Notes for Electronic Control Sy
7、stems.35.12 Mounting.25vii05-34-Microprocessor-Based Digital Blending System.25-35-Typical Digital Blender System.225-36-One-Tube System,Field Controller with Remote Receiver.245-37-Two-Tube System,Field Controller with Remote Receiver and Loading245-38-Three-Tube System,Field Controller with Remote
8、 Receiver,Loading Sta-tion,and Controller Output Indicator.255-39-Four-Tube System,Field Controller with Remote Control Station.255-40-Five-Tube System,Field Controller with Remote Control Station.25Part I-Process Instrumentation and ControlSECTION 5-CONTROLLERS AND CONTROL SYSTEMS5.1 ScopeControl a
9、ction,proportional,provides a continuous linearrelationship between the output and the input.This section presents recommendations for the applicationControl action,integral(reset),provides an output thatand installation of automatic controllers and control systems.is proportional to the time integr
10、al of the input(that is,theA brief discussion of programmable controllers is also in-rate of change of the output is proportional to the input).cluded.Definitions of control terms are provided,and con-Control action,derivative(rate),is that component of thetroller types are described.A presentation
11、of distributed con-control action for which the output is proportional to the ratetrol systems,other than user programmable,is included.of change of the input.Computer-based control systems that are user programmableControl action,proportionul plus integral(reser),providesare covered in RP 550,Part
12、I,Section 14.an output that is proportional to a linear combination of theModes of control most frequently applied in the refininginput and the time integral of the input.industry are discussed along with an empirical approach toControl uction,proportional plus derivutive(rate),pro-controller tuning
13、.Special control applications,such asvides an output that is proportional to a linear combinationcascade and feedforward,are also discussed,including digitalof the input and the time rate-of-change of the input.blending systems.Control action,proportional plus integral(reset)plusSome of the environm
14、ental and safety considerations forderivative(rate).provides an output that is proportional tothe location and mounting of controllers are discussed.the linear combination of the input,the time integral of theGuidelines are provided to aid in the design and installationinput,and the time rate-of-cha
15、nge of the input.of both pneumatic and electronic control systems.FinallyControl.direct digital,is control performed by a digitalsome considerations for acceptance testing and check out aredevice that establishes the signal to the final controllingreviewed.element.Controller,direct acting,is a contr
16、oller in which the value5.2Referenced Publicationsof the output signal increases as the value of the input(measured variable)increases.The latest edition or revision of the following publicationsController,reverse acting.is a controller in which theare referenced in this textvalue of the output sign
17、al decreases as the value of the inputANSI(measured variable)increases.MC85.IM Terminology for Automutic ControlA control systemn consists of the hardware and softwaredevices necessary to satisfy functional requirements of anISA2S51.1 Process Instrumentution Terminologyoperating facility.Dead band i
18、s the range through which an input can bevaried without initiating a response.5.3Terms and DefinitionsA direct connected controller receives its inputs directlyThe following terms are used frequently in this text.Thefrom the process by electrical,mechanical,or hydraulicdefinitions presented are base
19、d on ANSI MC85.1M.means.Distributed control systems are configurable multiloop con-An automutic controller is a device that operatestrol systems in which the user defines the control arrangeautomatically to regulate a process variable.This is ac-ment within a rigorous format provided by the plished
20、by comparing a measured process variable withDistributed control systems are generally not considered userthe desired value of the variable,called the set point,andprogrammable.generating an output signal to a control element.Guin.proportional,is the ratio of the change in outputdue to proportional
21、control action to the change in input.Gain,derivarive action,is the ratio of the maximum gainAmerican National Standards Institute.1430 Broadway.New York,Newresulting from proportional plus derivative control action toYork 10017.Instrument Society of America.PO Box 12277.Research Triangle Park,the gain due to the proportional control action aloneNorth Carolina 27709.(sometimes referred to as rate gain)
