Regarding the question of following control on the assembly line

I've solved it
1. Synchronization problem of gantry and conveyor belt, use an external encoder to record the position of the conveyor belt

I want to use vision to determine the location of the item, and I can achieve this too.
When items are placed on the conveyor belt, they will continuously place items on the conveyor belt. My camera and program will also constantly collect images to calculate the location of each item.
I can generate G code to control its running.
But I can't solve multiple G-codes at the moment (the continuous stream of items are placed on the conveyor belt) when will they start running
Ideally, the running signal of each G code is triggered by the encoder position.
But I don't have a good idea to achieve this. Does anyone have a better solution or idea?
 

spam removed

Yes, it is true~ I have considered such a solution, but the communication delay of the upper and lower machines is unpredictable

If we are speaking about communication delays, we also have to speak about communication delay between PC and camera.

After all, what is the speed requirement of the belt after all? Is it 0.1m/s? Is it 1m/s?