How to input transfer function into Labview ?

[Choong]

Hi everyone,

I'm trying to control a DC motor using PID toolkit 8.2, it is a close loop control system where there's an encoder sensor on the feedback side

I'm using a DAQ card model: NI USB-6008, i want my sistem will be able to output pwm signal to my motor
1) I'm getting stuck on how to input the transfer function into the Labview

2) I wanted to know what is Process Variable

3) What is the output of the pid.vi

If can pls make an example VI for me
Thanks

[Lee.P]

Below are the information to your questions. You may want to refer to LabVIEW help of PID.vi for more information.

1) I'm getting stuck on how to input the transfer function into the Labview

 You can convert your transfer function to find their P, I, D value and input into the PID Gains of PID.vi.

2) I wanted to know what is Process Variable

Process variable is the variable that is being controlled. If you want to control the speed of your motor, the process variable is the speed/rpm obtained from your encoder.

3) What is the output of the pid.vi

I will assume that you are controlling the speed of your motor. Hence, the Output Range will be the PWM range that is to be output to your motor. It can be 0-100% duty cycle. The Output of PID.vi will be a value from 0-100% duty cycle. You can then use this output value to output a PWM signal that is feed to your motor. The value of Output will vary according to the Process Variable and PID Gains.

Hope the above information is useful to you.

Thank you & Regards

Lee

NI ASEAN