Good building mechanical design requires a firm grasp of the mechanical engineering fundamentals (thermodynamics, psychrometrics, the fan laws, etc.). The same can be said about the BAS design needed ...

The first thing you may want to do is check if the default control loop (i.e. the PID settings that the product is delivered with) is good enough in terms of stability and load transient performance.

Only through proper troubleshooting and then solving the underlying problems can control loop performance be improved. Process design certainly plays a role in control loop performance, but experience ...