User`s manual

16-12 Motion Mate™ DSM314 for Series 90™-30 PLCs User's Manual – January 2001 GFK-1742A
16
Notes
1. The CAM instruction is not permitted in a Multi-Axis motion program.
2. A CAM command counts as two instructions towards the 1000 instruction limit in a motion
program.
3. The Profile Names
UDT_CAM_1
,
UDT_CAM_2
,
UDT_CAM_3
and
UDT_CAM_4
are
reserved for future usage.
The
<distance>
argument in the CAM command is used to define the maximum distance the
master can travel through the profile before exiting. For Cyclic CAMs, the distance can be either
greater than or less than the length of the CAM table (defined as the absolute difference between
the first and last master positions in the CAM table). If the distance is less than the length of the
table, the CAM command exits once the distance has been traversed. If the distance is greater than
the length of the table, the CAM will cycle through the CAM table until the distance is reached.
Thus, the user may set up the number of times a Cyclic CAM should be executed. For example, a
distance of 2.5 times the length of the CAM Table Master Position will cause the CAM profile to
execute two and one-half times and then exit. For non-Cyclic CAMs, the specified distance cannot
exceed the length of the table.
The distance can also be specified as “NONE”. For a Cyclical CAM, this will result in continuous
CAM motion until a CTL bit triggers an exit or motion is aborted. For a non-cyclical CAM,
specifying “NONE” means the CAM will exit when it reaches either the minimum or maximum
master position of the profile.
The [
master mode
] is used to specify whether the master axis operates in Absolute or Incremental
mode. The master axis may be operated in absolute or incremental mode for both Cyclic and Non-
Cyclic CAMs. In Absolute mode, the master positions in the table represent the absolute positions
of the master axis. In Incremental mode, the slave axis positions in the table are relative to the
master axis position when the CAM instruction is initiated.
The
[Cyclic Exit Condition]
is used to specify an exit condition for a Cyclic CAM profile. If the
CTL condition evaluates to TRUE, the CAM will exit at the end of the current cycle.
Bi-directional
and
Unidirectional
CAMs can be defined by using the +Vlim and -Vlim master
axis velocity limit parameters. For Unidirectional operation, the appropriate velocity limit must be
set to zero for the direction in which motion is prohibited. For example, if motion in the negative
direction is prohibited, then –Vlim must be set to zero.