Controlled stop from carteian position check zone behaving like an ESTOP

I have a DCS CPC zone setup with a light curtain set up as a disabling input for it. The light curtain signal is fed through a CPI signal from a CompactLogix safety PLC. I have it setup so that if the robot is in the zone and the LC is broken, it will do a controlled stop. However, whenever these conditions are met, the robot instantly jerks HARD like an ESTOP instead of the quick deceleration before applying the brakes. I know that I don't have anything in the PLC overriding this zone and estopping it because 1. the robot does not enter an ESTOP state, and 2. I tested setting up the stop type as "no stop" and breaking the LC, and the robot kept moving along. Has anyone here run into something like this before?

Quote from scotty

What robot speed do you have inside of this zone and what is the payload? Could it be inertia?

It happens even if I'm running slow at 5%. It is an instant stop. I have tried using payload and inertia data from both CAD data, and from the auto identify. The issue persists with both. It it a 110kg payload on a R-2000iC 210F robot, which has a payload of 210kg.

Quote from retobor

Is stop prediction enabled and causing this? Do you get an alarm?

It is enabled in the CPC zone settings, but under the Stop Position Prediction setup menu, it is disabled. The only error message that I get is SRVO-402 DCS Cart. pos. limit

Quote from scotty

Do you have alarm 'SRVO-199 Controlled stop' during the breaking light curtain? If yes, then Controlled stop works right.
I will say try to change your DCS to Power-off and compare result. Because Controlled stop reacts immediately and stop not always gentle.

No, I do not get that alarm. The only alarm that I get is SRVO-402 DCS Cart. pos. limit. I can try testing it out with power-off stop and see what it looks like.

I have been talking to Fanuc, and they say that this behavior is normal, which might be true. I only raise the question because I work a lot more with ABB robots and safemove, and in my experience under the same conditions, the robot stops a LOT more gently compared to what the Fanuc is doing.

I just wanted to update this thread so that others can know what the issue was. Fanuc got back to me finally after looking at my backup, and here is their response:

"Our investigation has concluded that your robot is loaded with the enhanced stopping option which is also known as a Stop Pattern type B. enhanced Stopping option J692 option installed. Which from what I see in the DCS manual means all stops whether initiated by Controlled stop or estop are treated as full power off stop. This option will require a re-burn of software to remove."

So it is an option for the robots apparently. Hope this can help others with the same issue!