1) Check that the photo eye is 65mm's from the center of the back fold hook when the hook is at the home position. This will ensure accurate settings when setting up a make ready.
2) The photo eye should have a clear path through the machine to ensure an accurate reading. If there is any obstruction or flutter from the carton that is being read, an error code could be generated and fault out the system.
3) Always operate your equipment safely!