Danfoss AKD 5001 Manual

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Danfoss AKD 5001 Manual Manual pdf 55 page image

AKD 5000 PID for process controlFeedbackThe feedback signal must be connected to a terminalon the frequency converter. Use the list below todecide which terminal is to be used and whichparameters are to be programmed.Feedback type Terminal ParametersPulse 33 307Voltage 53 308, 309, 310Current 60 314, 315, 316Furthermore, the minimum and maximum feedback(parameters 414 and 415) must be set to a value inthe process unit that corresponds to the minimumand maximum value on the terminal.Select process unit in parameter 416.ReferenceA minimum and a maximum reference can be set (204and 205), which limit the sum of all references. Thereference range cannot exceed the feedback range.If one or several setpoint references are required,the simplest way is to set such reference directlyin parameters 215 to 218. Select between thepreset references by connecting terminals 16, 17,29, 32 and/or 33 to terminal 12. Which terminalsthat are used depends on the choice made in theparameters of the various terminals (parameters300, 301, 305, 306 and/or 307). Use the tablebelow when selecting preset references.Preset ref. msb Preset ref. lsbPreset ref. 1(par. 215)0 0Preset ref. 2(par. 216)0 1Preset ref. 3(par. 217)1 0Preset ref. 4(par. 218)1 1If an external reference is required, this can eitherbe an analogue or a pulse reference. If currentis used as a feedback signal, only voltage canbe used as an analogue reference. Use thefollowing list to decide which terminal to use andwhich parameters to program.Reference type Terminal ParametersPulse 17 or 29 301 or 305Voltage 53 or 54 308, 309, 310 or311, 312, 313Current 60 314, 315, 316Relative references can be programmed. A relativereference is a percentage value (Y) of the sum ofthe external references (X). This percentage valueis added to the sum of the external references,which produces the active reference (X + XY). Seesection Handling of multi references.If relative references are to be used, parameter 214 is tobe set to Relative [1]. This makes the preset referencesrelative. Furthermore, Relative reference [4] can beprogrammed on terminal 54 and/or 60. If an externalrelative reference is selected, the signal on the input willbe a percentage value of the full range of the terminal.The relative references are added with signs.NB!:Terminals that are not in use should preferablybe set to No function [0].Inverse controlIf the drive has to react with increasing speed onand increasing feedback, Inverse must be selected inparameter 437. Normal control means that the motorspeed decreases when the feedback signal increases.Anti WindupThe process controller comes with the anti windupfunction in active position. This function ensuresthat when either a frequency limit or a torque limitis reached, the integrator will be set to a gain thatcorresponds to the actual frequency. This avoidsintegrating on an error that cannot in any case becompensated for by means of a speed change.Start-up conditionsIn some applications, optimum setting of the processcontroller will mean that it takes an excessive timefor the desired process value to be reached. Insuch applications it might be an advantage to fix amotor frequency to which the frequency converter isto bring the motor before the process controller isactivated. This is done by programming a ProcessPID start frequency in parameter 439.Lowpass filterIf there are oscillations of the current/voltage feedbacksignal, these can be dampened by means of a lowpassfilter. Set a suitable lowpass filter time constant. Thistime constant represents the limitfrequency of theripples occurring on the feedback signal. If the lowpassfilter has been set to 0.1s, the limit frequency will be 10RAD/sec., corresponding to (10/2 x π) = 1.6 Hz. Thiswill mean that all currents/voltages that vary by morethan 1.6 oscillations per second will be removed bythe filter. In other words, control will only be carriedout on a feedback signal that varies by a frequency ofMG.50.R3.02 -54