block diagram for a pid controller in labview

Temp1 sensor in the outmost position Duration of experiment: 60 secondsīlind control: Control Manual feedback: Automatic feedback (PID): Setpoint Filtered temp The process is operated as follows: Setpoint = 40% (fixed) Fan speed = 60% (initial value) A disturbance change: Increasing the fan speed for about 10 sec from 60% to 100% and then back to 60% again. order Butterworth with bandwidth 0.4Hz.ġ0 Trying out three control strategies cont. (found from the LabVIEW PID Autotuning.vi with ”fast response”). the computer does the control For the PID control: PID settings: Kc = 40,8 Ti = 8.0s Td = 2.0s. the human (student) does the control Automatic feedback (PID) control, i.e. control with a fixed control signal Manual feedback control, i.e. The three performance indexes (|e|max, |e|mean, |du/dt|mean) are recorded for each of the below control strategies: Blind control, i.e. The mean of absolute error index: can be implemented with the following code: (Alternatively, could have used the MeanPtByPt.vi.)Ĩ Implementation of performance indexes cont.Īnd the control signal time-derivative index: can be implemented with the following code: (Alternatively, could have used the MeanPtByPt.vi.) The maximum control error index: can be implemented with the following code:ħ Implementation of performance indexes cont. The three performance indexes defined above can be implemented as follows. MPC, where the objective function includes the variation of the control signal.) Should be small or large? Maximum of absolute value of control error: Should be small or large? Mean of absolute value of control error: (Almost the same as the popular IAE index – Integral of Absolute value of control Error.) Should be small or large? Mean of absolute value of time-derivative of control signal: (Inspired by optimal control, e.g. The students will implement this system from scratch in LabVIEW.ĥ Some performance indexes of control systems 3 x Voltage AI (Temp 1, Temp 2, Fan indication) 1 x Voltage AO (Heating) Fieldpoint FieldPoint (Dual Channel Voltage I/O) PWM indicator Pt100 sensor (secondary) AC/DC Pulse Width Modulator (PWM) Air tube Fan Heater RS232 Serial Air Pt100-mA transducer Pt100 sensor (primary) Fan speed adjust Laptop PC with LabVIEW P C laptop. Finn Haugen, Telemark University College, Norway Contents of the presentation: Description of the case (student assignment): Temperature control of heated air tube Block diagram of control system Performance indexes Control strategies (Blind Manual feedback Automatic feedback.) Measurement noise Easy controller tuning Gain scheduling (adaptive control) Feedforward control (added to feedback control) helloģ Case: Temperature control of air heater with LabVIEW Learning PID control essentials with LabVIEW By Assistant Prof. Telemark University CollegeNational Instruments Confidential

Block diagram for a pid controller in labview