This is what I found from ArcTool Manual... Hope it helps
Speed Ramping Overview
You can use the speed ramping function to specify a motion based on smooth speed change throughout the motion segment (instead of constant speed) from the starting position to the destination position.
The following program has speed ramping specified on line 3.
The motion on line three starts with a speed of 100mm/sec. As the robot approaches P, the speed
gradually increases to around 200 mm/sec.
You can specify speed ramping through the motion option menu, select RampTo from the menu, and the motion line will show: