Here, I have some problem with my servo controller/driver units. I am using this servo controller/driver for a few similar machines. This servo motor is used to perform indexing for a tape-and-reel application. A pin-wheel is mounted on the servo motor shaft and this is used to pull the tape. Besides that there is also a home sensor for detecting the tape's holes. When the sensor is triggered, it shows that the position is reached and I.C chip can be placed into the tape's hole. A fix distance is performed before searching for the home sensor. The problem is my servo motor will sometimes search for home sensor in reverse direction after we run the machine for few thousand indexes. Can anybody here help on this? I believe this is caused by electrical noise but when I put a capacitor of 0.1 micro farad between the home sensor signal and home signal ground, it solved only 2 machines out of 4. The other 2 machines was perfectly run for all these while and suddently with this capacitor, the motor reverse its direction again quite often. Please help.