## Introduction To Labview For Control Design Amp Simulation-Free PDF

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To start a new program called VI for Virtual Instrument click Blank VI. Block Diagram,programming,Front Panel,user interface. Figure 2 LabVIEW new VI, Click in the block diagram to view the area where graphical programs are written Right click inside. the block diagram to view the palette of functions used in creating programs Select the Control Design. Simulation Simulation palette to view the library of simulation functions. Figure 3 Simulation functions sub pallette,In Control Design Simulation pallette. In the next section you will build a model of the open loop system for the process mentioned earlier and. determine the unit set point and unit disturbance responses The following steps will guide you. through the discussed tasks, Construction of an Open Loop Block Diagram Chapters 4 5 6 and 7. 1 Open a new VI by selecting File NewVI The new window will be titled untitled You will. build your closed loop model in the block diagram Save the empty model by choosing File. Save Name the model examplesim From this point on the model will be referred to as. examplesim, 2 Click on the block diagram then right click to bring up the functions palette From the.
Simulation sub pallette click and drag a simulation loop on the block diagram. Click and drag to,create Simulation loop, 3 Place the Transfer Function and Transport Delay blocks from the Continuous. pallette respectively to Examplesim Connect the output of the Transfer Function block. to the input of the Transport Delay block Click on the Transfer Function label and. rename to Process TF This block represents the process Note that in this problem. the process is G s GvGpGm not Gp,Open the dialog,box of Process TF by double. clicking on it Specify,Numerator as 2 and,Denominator as 1 15 50. This indicates the transfer,function 2 50s2 15s 1,The Transfer Function block. allows specification of vectors,for the numerator and.
denominator from either a,configuration dialog box. or a terminal from the,block diagram The vector,elements are treated as the. coefficients of ascending, powers of s in the polynomials representing the numerator and denominator of the. transfer function To see the denominator polynomial of s completely displayed. in the block s icon you may have to resize the block s icon. Double click on the Transport Delay and set Time delay to 1 Note that the Transport. Delay block can be used to represent other types such as measurement delay. 4 Copy the Process TF and Transport Delay blocks and place the copies slightly. above the originals The copies will automatically change names to Process TF1 and. Transfer Delay1 To quickly copy the original blocks select both of them hold the. CTRL key and drag using the left mouse button Rename the Process TF1 block. Disturbance TF In this example Gp and Gd are the same so the Numerator and. Denominator parameters in the dialog box of Disturbance TF are not changed See Figure. 5 Place a copy of the Summation block located in the Signal Arithmetic pallette to the. right of the Transport Delay block Right click on the summation block and select. Visible Items Label to see the label Summation Connect the output from each. Transport Delay block to the input of the Summation block The number of inputs and. their polarity can be modified from the dialog box Later in the tutorial you will be. required to do this, 6 Place a SimTime Waveform graph from the Graph Utilities palette to the right of the. Summation block Connect the output of the Summation block to the input of the. SimTime Waveform block,7 Place a Step Signal block.
from the Signal Generation,palette to the left of,Disturbance TF and connect. it to the input of Disturbance,TF The Step Signal block. generates a step function,The initial value final value. and step time time at which,the step occurs of the. function can be specified,For now double click to,open its dialog box and set.
the initial value and final,value and step time to zero. i e disabling the block Rename the block D, 8 Place a copy of D to the far left of Process TF and rename the new block U Connect. U to the input of Process TF Double click on U and set Step time to 0 Initial value to 0. and Final value 1 U will generate a unit step function in the manipulated variable at time. zero The model developed to this point is a model of the open loop system It should. look similar to the model below, 9 Now we are ready to simulate the open loop response of the system To. select the integration technique and parameters to be used during simulations double. click on the left terminal of the Simulation loop,simulation. Figure 4 Open Loop Block Diagram,A dialog box is opened showing all the.
simulation parameters that can be modified,Set the Final Time to 50 and the Max Step Size. to 1 Note that the LabVIEW Simulation loop,includes an ODE solver The maximum step. size determines the largest step LabVIEW uses,in numerically integrating the ODE Since. this system is easy to numerically integrate a,max step size of 1 will result in a smooth curve. Larger step sizes will produce more jagged, Run the simulation by clicking the Run arrow on either the front panel or the block.
diagram Hint Ctrl E switches between the front panel and block diagram. 10 The response will be automatically plotted Double click on the title to change the name. of the plot You can also right click on the plot to view axis settings autoscaling and. other plot parameters,Figure 5 Unit step response of open loop system. 11 Now simulate the open loop unit disturbance response Double click on U and set final. value to 0 This eliminates the unit step in the manipulated variable Double click on D. and set step time to 0 and final value to 1 This creates a unit disturbance step Again hit. the Run arrow to begin the simulation The front panel will show the response Double. click on the graph title to replace Step Response Open Loop with. Disturbance Response Open Loop Figure 6 shows the resulting plot. Notice that the open loop set point response and disturbance response are the same Why. is this expected, Figure 6 Unit disturbance response of open loop system. 12 If you are not continuing to the next section save the file examplesim so that you can use. it in constructing a closed loop block diagram, Construction of Closed Loop Block Diagram Chapters 11 and 12. 1 Open the file examplesim if it is not already open. 2 Click on the connection between the U block and Process TF block and delete it. Rename the U block to Ysp This block will be used to produce a step change in the. 3 Place a copy of the Sum block to the right of Ysp It. will automatically be given the label Summation2, Open its dialog box and change the the lower input. from to The top input will have a located to the, right of it while the bottom input will have a located.
above it Therefore the output of Summation2 will,be the top input minus the bottom input. Connect the output of Ysp to the top input of Sum1. Also connect the output from Sum to the bottom,input of Sum1 This can be done by clicking on the. bottom input of Sum1 and dragging the arrow to the. output of Sum The output of Sum1 is the error,between the set point Ysp and the controlled. variable Y Your model should look like Figure 7,Figure 7 Partially Completed Closed Loop Diagram. 4 We are now ready to add the PID feedback controller. to the loop There are several versions of the PID,controller block available in LabView however for.