How to modify a continuous rotation servo motor MG996R to stop for actuated valve purpose?

[tichuaryan]

Hi everyone, I am a final year student inquiring about my graduation project. I am building an actuated globe valve using a servo motor MG996R and Arduino MEGA 2560 to control the blockage level of the valve eg 25%, 50%, 75% and 100% blockage to induce a cavitation effect and to control the opening and closing of the water valve.

I used an example VI from LabVIEW. The VI is running well, but I can not seem to stop the servo motor from rotating as shown in the video, which leads the valve's head to be disconnected from the valve body. This is because I am using a continuous rotation servo motor MG996R. I already tried using a non-continuous servo motor MG995, which doesn't work as the globe valve requires continuous rotation to open and close. 

My skill in LabVIEW is moderately low as I am learning as I go. I appreciate it if anyone can help/guide me to solve this issue. Below are the details about my project for your information.

Servo motor: MG996R 360° (continuous rotation)
Type of valve: Globe valve

Backward position: 0-89°

Stop position: 90°

Forward position: 91-180°

Attached is the VI of the project for your reference.

[jorgemondadori]

Hey tichuaryan

Since it is not a LabVIEW project, i'll try to provide some insights for you.

I did something like that for my graduation project as well! i used nema 17 stepper motor with an encoder to provide feedback from the valve position.

I believe that you need this kind of feedback to control your valve, to stop, open or close.