text: <s>[INST] Motion Tracking Error At Higher Speeds I am interested in a way to reduce the tracking error in a CIP motion application. The system has two PowerFlex 755 drives operating in CIP motion. The master axis is connected via a non-synchronous belt to a press. Attached to the press is an 842E motion encoder, which the slave axis tracks via a MAG instruction. The problem is that as speed increases, the phase lag of the slave axis increases. In order to correct this I use series of MAM steps to phase advance and retard over the speed range, but I would like to find a better solution. Any input appreciated, thanks. [/INST] When you say non-synchronous belt you're talking about a V-belt or flat belt, right? No chance of changing it to a timing belt or chain drive? Could you gear the slave to the master drive instead of the intermediate encoder? What about using the motion axis registration function (MAR)? https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/26388/loc/en_US You may have to trend the master position, encoder position, and slave position to try to quantify the slippage and write your own compensation algorithm. One possible method would be to use a virtual axis slaved to the master that emulates the encoder. It would provide the no-slip position information and the delta between the virtual and the encoder would be the correction you need to apply to the slave. \\n </s>