Experiment - External-Cavity Diode Lasers (PID Loops / Electronics)

Apparatus

Our apparatus for this experiment consists of a few main components.

1. Laser block

Procedure

We will be assembling

Ziegler-Nichols tuning

The most important part of configuring the PID controller is setting the constants $K_p, K_i, K_d$. We will be following the Ziegler-Nichols method for tuning.

1. Turn off the Integral and Derivative components for the controller; only use Proportional control

2. Slowly increase the gain (i.e., $K_p$) until the process starts to oscillate. Measure the final gain value is known as $K_u$; and the period of oscillation as $T_u$.

3. We can set the PID variables using the following table

Controller	K_p	K_i	K_d
P	K_u / 2
PI	K_u / 2.5	T_u / 1.25
PID	0.6 K_u	T_U / 2	T_u / 8

References

Piezo Driver - Link

TEC and laser driver - Link

https://www.crystalinstruments.com/blog/2020/8/23/pid-control-theory