We generally advise that moveJ accelerations should be less than 800deg/sec^2 and moveL accelerations < 2500mm/sec^2. However, the jerk you are seeing might be caused by other factors. It is generally a very bad idea to drip feed individual servoj commands to the robot over the client interfaces, there is potential to starve the controller for trajectory data or send it too soon. So IF you ARE doing this then I would look for a different solution. If you are still unsure about proper use of servoj I suggest searching the forum and seeing what others have learned. Here is a good place to start : Usage of servoj