Omron SYSMAC CJ Operation Manual page 358

Practical examples
5-2-10 Correction program
5-2-10-1 Example
346
A new movement starts (step 2).
This application is for a rotary labeller. The constants are:
• The product arrives on a conveyor (master axis) that runs at a constant
speed.
• A rotary labeller that is synchronized 1:1 to the conveyor, attaches the
labels.
• The distance between products is fixed and mechanically guaranteed.
The distance between labels is never exactly constant so, a correction is
needed. This is done by superimposing a virtual axis onto the movement of
the labeller.
The difference between the expected position and the actual position is
measured with a photocell. This is the correction factor.
Every time a correction is made, the origin position is updated accordingly.
speed
correction
conveyor=0
labeller=1
virtual=15
SERVO AXIS(conveyor)=1
SERVO AXIS(labeller)=1
WDOG=1
BASE(labeller)
CONNECT(1,conveyor)
ADDAX(virtual)
FORWARD AXIS(conveyor)
REGIST(1)
WAIT UNTIL MARK=0
loop:
WAIT UNTIL MARK
correction=REG_POS+expected_pos
MOVE(correction) AXIS(virtual)
WAIT IDLE AXIS(virtual)
OFFPOS=-label_length+correction
REGIST(1)
WAIT UNTIL MARK=0
GOTO loop
OFFPOS
0 0
labeller
Section 5-2
0
conveyor
t