User`s manual

Follower Motion
GFK-1742A Chapter 8 Follower Motion 8-7
8
inputs have 5 ms filters that result in a Follower Enable Trigger response time of 5-7
milliseconds. The faceplate 5v inputs do not have these filters and will provide an Enable Trigger
response time of 2 millisecond or less.
When the
Enable Follower
trigger occurs, the
Commanded Position
at that point is captured in a
parameter register so that it can be used in a
Programmed Move
command. The position is
captured in parameter 226 (for Servo Axis 1), parameter 234 (for Servo Axis 2), parameter 242
(for Servo Axis 3) or parameter 250 (for Servo Axis 4).
Follower Enabled
status is returned in a %I bit for each axis.
Disabling the Follower with External Input
Any CTL bit CTL01- CTL32 can be configured as a Disable Trigger for the follower axis. The
trigger input is tested only when the
Enable Follower
%Q bit is ON. When the
Enable Follower
%Q bit is ON, an OFF to ON transition of the trigger bit will disable the follower. Turning OFF
the
Enable Follower
%Q bit immediately disables the follower, regardless of the disable trigger
configuration.
Follower Disable Action Configured for Incremental Position
Configuring the
Follower Disable Action
for Inc Position allows the follower axis to perform an
Incremental Registration Move
. Disabling the follower with the
Enable Follower
%Q bit or
optional
Disable Trigger
will cause the axis to continue at its present velocity, then decelerate and
stop after a specified distance has elapsed. The incremental distance is specified in a parameter
register for each axis:
P227 = Axis 1 Incremental distance
P235 = Axis 2 Incremental distance
P242 = Axis 3 Incremental distance
P250 = Axis 4 Incremental distance
The incremental distance represents the total actual position change that will occur from the point
where the follower is disabled until it stops. Superimposed motion commands (
Jog, Move at
Velocity
or Motion Programs) should not be active during a Follower Registration Move.
Follower Axis Acceleration Ramp Control
For applications where the Follower is enabled after the Master command is already up to speed,
the Follower Ramp feature can be used to apply a controlled acceleration rate to bring the follower
axis up to speed. This may be done without losing any Master command counts from the point at
which the Follower was enabled. During the automatically generated Follower Ramp Control
make-up move, the acceleration/deceleration does not exceed the configured
Follower Ramp
Acceleration
value and provides a smooth motion. When the follower is enabled, the slave axis is
ramped up to the master velocity at the active configured
Follower Ramp Acceleration
rate. This
function is most useful when the master source is in motion before the follower mode is enabled.
In addition to the PLC Enable Follower %Q bit, a CTL bit (CTL01-CTL32) may be configured as
the enable follower signal for position registration functions. When the
Enable Follower
%Q bit