This feature "Marking On The Fly" (MOTF) is for marking moving targets on a product line. General information on a (MOTF) setup is given here.
In sub-chapters, further detail is given on how to work with encoder signals or without them in simulation mode, on the card-specific hardware setup, on how to calibrate a MOTF system and on the possibility of doing endless MOTF or rotational MOTF. Finally, some examples can be found at the end.
Figure 252: A typical MarkingOnTheFly (MOTF) setup
The target piece which has to be marked is placed on a moving conveyor belt that surpasses the scan head at a specific position. The scanner has to know when to start marking and how fast the target is moving. Latter is done by the encoder: The movement of the target is converted by the encoder. For a specific distance of the target (in the above example along the X-axis), the encoder gives a specific amount of counts. The information of this conversion is given by the multiplier. Movement is possible in different directions. The distance information from the encoder is sent to the scanner card which appropriately corrects the marking vector such that it fits to the moving target. The starting signal is sent by the trigger sensor: The sensor converts a specific optical label on the conveyor belt into an electrical trigger signal.
The MOTF_CH0 (on the 37-pin connector) and MOTF_CH1 (on the 40-pin connector) signals are filtered by a digital filter unit. For information on the cut-off frequency, see the corresponding hardware manual. After the decoding, a counter counts the incoming count pulses and is incremented or decremented according to signal (see encoder signals for further details). In some application the belt movement direction and speed remains constant. In this case the counts can be generated by an internal simulation generator eliminating the need for an encoder.
In order to calibrate the counter according to the scanner field units [typically in bits, mm or inch], the counter value is multiplied by a user definable signed constant. The resulting MOTF compensation is added to the marking information to form the final signals for scan head control.