User`s manual

9-2 Motion Mate™ DSM314 for Series 90™-30 PLCs User's Manual – October 2000 GFK-1742A
9
Follower Motion Combined with Motion Programs
Motion commands from stored programs or the
Move
%AQ command can also be combined with
the master command to drive the follower axis. These point-to-point move commands can come
from one of the stored motion programs 1 through 10 and any stored subroutines they may call.
The
Move
%AQ command is treated as a single line motion program, which uses the present
Jog
Velocity
and
Jog Acceleration
. Program execution is started by the PLC setting an
Execute
Program n
%Q bit or sending a
Move
%AQ command.
If there is no master command, the axis can be commanded solely from the stored motion program
data. Thus, with no master input to Servo Axis 2 and Commanded Position 2 selected as the
master source for Servo Axis 1, a stored program can be used to control Servo Axis 2 with Servo
Axis 1 following per the designated ratio.
When PMOVEs are executed with Follower not enabled, the
In Zone
%I bit must be set at the end
of the move before programmed motion will continue. When Follower is enabled, since
In Zone
may not turn on while also following a master command, the
In Zone
indication will not be
required to continue. The next Move will take place when the commanded distance for the
previous move has completed. The
In Zone
%I bit will always indicate the true in zone condition.
The active commanded position updated and used by the stored motion program is referred to as
Program Command Position. Each time a program is selected for execution, this position register
is initialized in one of the two ways listed below.
1. If the follower is
not enabled
, the Program Command Position is set to the current
Commanded Position
=
Actual Position
+
Position Error
.
2. If the follower
is enabled,
the Program Command Position is set to the Program Reference
Position
(0).
Since the Program Command Position is only updated by internally generated
commands (and not by the master command), it will then indicate the position commanded by
the stored program. Absolute move commands from the stored program will be referenced to
the Program Reference Position.
Position ranges (in counts) for the Actual and Program Command Position registers are indicated
in the figure below.
Fixed
-2B
Fixed
+2B
Lo Limit (max)
H
i limit (max)
-536M
0
+
536M
Program
Position Range
Actual Position
(from Feedback)
With sustained commanded motion in the same direction, the Program Command Position will
roll over at +2,147,483,647 or –2,147,483,648 counts
The Actual Position, however, will be confined by the configured
High Position Limit and Low
Position Limit
.