Omron SYSMAC CJ Series, Operation Manual

Page: 325 / 371

How-to’s Section 5-1
313
5-1-6-10 Example: Starting a slave axis in precise position of a master axis
The picture shows a flying shear cutting the "head" of wood tables. When the
wood comes, the edge of the wood is detected by the photocell and, at the
exact moment, the movement of the flying shear starts to be synchronized with
the right position on the wood.
If the movement is started by the program, upon detecting a signal from the
photocell, there is always at least one
SERVO_PERIOD of time of uncertainty.
Instead, the movement is started using the MOVELINK command with
link_option =1, which means that the link to the master axis starts when the
registration event occurs on link (master) axis.
The corresponding program sequence is:
REGIST(2) AXIS(master)
MOVELINK(dst,lnk_dst,lnk_acc,lnk_dec,master,1) AXIS(slave)
For more information on the MOVELINK command and the link_option
argument, refer to section 4-2-159.
The picture shows how the position of the slave axis is corrected using the
registration event on the master axis to start the movement of the slave axis.
The influence of
SERVO_PERIOD and the fact that the registration event can
happen at any time inside the SERVO_PERIOD is completely eliminated.
E
E
Master axis
Slave axis Flying shear
Transporting belt
Master Speed
Slave Speed
Servo Period
Correction in the slave
according to the latch.
Extra position the first
cycle is equal to the
“lost” position
Registration input signal