This is a standalone PID Control Trainer. In this trainer, the PID functions are derived from discrete electronics. This trainer has the following blocks to accomplish PID experiment derived from discrete functional blocks. The functional block diagram explains the fundamental blocks required in a 3-TERM controller. They are
Input Block: Input block contains a potentiometer to vary the set point (SP), which can be varied in the range of from 0-5V DC. Comparator Block: Set point and the feedback from the process is compared here. The output from the comparator is the difference between set point and feedback from the process. It is possible to give the comparator output as input to either one or all the PID blocks. It is recommended to study the nature of process variable (PV) output for each of the following blocks. Later the benefit of connecting PI, and PID can be independently be studied. This approach will be beneficial to appreciate the reason why PI or PID controller is much preferred than using only P or I or D controller. The following process blocks are provided. They are Proportional Block: Error signal from the comparator output can be connected as an input to the proportional block. Output from proportional block is proportional to the error signal. The proportional gain can be set in the range of 0 to 100% in 10-decade steps. Integral Block: Error signal from the comparator output can be connected as an input to the Integral block. Output from this block is the sum of all error signal in a time domain. The integral gain can be set in the range of 0 to 100% in 10-decade steps. Derivative Block: In order to connect the derivative block the output from the comparator should be given to the derivative block input
Summing Amplifier Block: Summing Amplifier is used to add the output from all controller blocks. Process Block: Here the process is simulated using Lead / Lag Network. Reset Function: Reset Function or Disturbance in the process is simulated by the user by a dedicated momentary switch. The final process variable can be observed on an oscilloscope at the output terminals. This can also be recorded using an external recorder for documentation purposes. |
