and disengagement points as those
where the speed change of the fol-
lower is most gradual.
The electronic cam is an ideal
mode for periodic operation, especially
those requiring varying gear ratio along
the motion cycle. Such applications
include flying shears, rotating knives
and packaging systems.
The following diagram shows the
cam table for a typical flying shear
application. It also shows the expect-
ed shear velocity when the master
speed is constant.
Dual Loop: The dual-loop encoder fea-
ture enables the DMC-1000 to com-
pensate for backlash. There are two
compensation methods. The continu-
ous dual loop, which performs the cor-
rection along the move, and the sam-
pled dual loop, which performs the
correction at the final point.
In both cases two encoders are
used for each axis. One encoder is
mounted on the motor and one is
mounted on the load. The continuous
dual loop, which is activated with the
instruction DV1, closes the position
loop with the load encoder and derives
the damping terms from the motor
encoder. This method provides back-
lash compensation along the motion
path. The sampled dual loop performs
the correction at the end of the move.
Homing: The home (HM) command
can be used to home each motor to an
external mechanical reference and an
encoder index signal. The home speed
(SP) is programmable and the polarity
of the home switch is selectable using
the (CN) command. Alternative hom-
ing sequences can be created with the
FE and FI commands.
Sinusoidal Commutation: The
DMC-1000 is available with the sinu-
soidal commutation option. In this
mode, the controller performs a sinu-
soidal commutation of brushless
motors and outputs the sinusoidal
signals necessary to drive the motor
phases. This method allows the use
of low-cost amplifiers, thereby reduc-
ing the system cost.
The initialization procedure can
be customized for the users, accord-
ing to the available sensors such as
incremental encoders, hall sensors,
absolute encoders, or resolvers.
M O T I O N C O N T R O L L E R S
ISA BUS
DMC-1000
DMC-1000 ISA Bus Controller
65
