What kind of drives do they have? What type of position encoder did they use? If they are 32 bit you may want to start a logfile to analize next time it comes in. I don't know this machine but I would want to put in 125% and make sure that main brake will hold. I recently had a Synergy that would creep up only at the bottom floor, re-level and repeat. Usually wouldn't even throw a fault but in certain cases I would get a UIM. Both brakes held 125% and counterweighting was right on. It was slipping traction and only at that one spot. The ropes were slightly smaller where they contacted the drive sheave with the car at 1. 200lbs on the car eliminated the problem and a re-rope solved it for good.
