Fanuc Line tracking(circular)

Hello all

I am working with a Fanuc R2000ib/150U with R30iA Controller, I am trying to get the robot to track a part being bent on a press brake, I have everything hooked up with the encoders and trigger, it works pretty well, problem is I am not sure how to get it to stop tracking, in other words the press moves down, clamps the part, I trigger the robot to start tracking which it does very well, but once the press is at the bottom of the stroke I need to stop tracking, so it doesn't track backwards at high speed as the press moves upward, I'm just not sure how to stop tracking.

I am using circular line tracking to follow the bend, the center of the tracking circle being the tooling of the press.

here is a sketch from the side of what I am trying to do.

any help is appreciated.

Thanks Nation for the answer. I will try that.

What seems to work fairly well is move to the press, wait for the command from the press to say part is clamped, start tracking program, in the tracking program I go PR1=JPOS and then move to position PR1, which is where the robot already is, but the next line is wait till DI1=off so it tracks in the position it is already at, till DI1 turns off from the press, meaning it is at the bottom of the stroke. It seems to stop tracking as soon as the DI1 turns off. Does this seem like a good way?

thanks again Nation.

the reason I have the JPos is because the robot will not always be starting in the same position, lets say the part is bigger and the robot is further away from the tooling, it will still track around the same "arc center" assuming its the same tooling in the press brake, but the starting position for the robot is different, this makes sense in my head at least.