RobotStudio event

Cannot log TCPx, y,z under OnlineAnalyzer

My robot arm model is IRB 2600 1.65/20, and Robotstudio connected to it via Ethernet cable.
I've tried to log the TCPx, y and z through online analyzer, but it didn't work. (the following  picture's URL)

However I've tried to log position of joints, and it did work. (the following picture's URL)

Why cannot I log the TCP ?