The autotuning parameter cluster has 2 control rings: controller type - P = 0, PI = 1, PID = 2 and control specification - normal = 0, fast = 1, slow = 2
When you select an autotune technique, these ring controls are connected to the input of the corresponding online autotuning VI, where they are linked to internal subVIs with similar ring controls. Call chains is shown below.
1. PID Online Autotuning (Step Open Loop).vi -->> PID Autotuning Design (Auto).vi -->> Type of Controller, Ziegler-Nichols Speed
2. PID Online Autotuning (Step Closed Loop).vi -->> PID Autotuning Design (Auto).vi -->> Type of Controller, Ziegler-Nichols Speed
3. PID Online Autotuning (Relay Feedback).vi -->> PID Table (Ultimate Gain and Frequency - Ziegler Nichols).vi -->> type of controller, control specifications
4. PID Online Autotuning (PID on the loop).vi -->> PID Calculate Gains.vi -->> Controller Type, Control
But these ring controls have different order of ring values in internal SubVIs!!!
The first three have the Ziegler-Nichols speed (control characteristics) ring order fast = 0, normal = 1, slow = 2. The first two values are swapped.
The fourth has the reverse order of the control ring values PID = 0, PI = 1, P = 2
Therefore, the PID auto-tuning mode does not work correctly.
Can anyone confirm this behavior? I am using LabView 2020 Community Edition. Possibly the same bug exists in other versions of LabView PID addon.
