Omron TJ2-MC64 - PROGRAMMING Programming Manual page 302

Examples and tips
The feeder can work in two modes: without registration mark; and with
registration mark. Working without the registration mark is a simple point-to-
point incremental movement. In this case, there is no guarantee that the
feeder moves exactly the same distance as the design pattern. For example,
suppose the bag length that needs to be fed is 200 mm, but the real pattern
is 200.1 mm. With simple point-to-point incremental movement without
correction, an error of 0.1 mm per bag is accumulated. With a small number
of bags the difference is not visible, but after 500 bags the error is 50 mm,
which is a 25% of the bag length.
When working with registration marks, the motion controller executes an
incremental movement to a certain position. If during the positioning the
registration mark is detected, the target position is changed on the fly in
order to finish the movement at a defined position after the registration mark.
Therefore, the same distance in respect to the registration mark is always
guaranteed.
PROGRAMMING MANUAL
fig. 38
∆d
20∆d
100∆d
After 1 bag After 20 bag
fig. 39
D
After 100 bag
296