Rockwell Automation MagneMotion MagneMover LITE User Manual

Operation
Theory of Operation
MagneMover LITE User Manual 319
Rockwell Automation Publication MMI-UM002F-EN-P - October 2022
old one left off for profile generation. The new master is now responsible to continue
the closed-loop control of the vehicle.
7. The motion order is finished when the vehicle position is equal to the ordered destina-
tion.
Motor Cogging
Brushless Permanent Magnet (BPM) motors that are iron core-based inherently exhibit cog-
ging forces. In traditional BPM motors, these cogging forces are felt when turning the shaft of
the motor and are periodic in nature. The periodicity in this case would be expressed in
degrees and the magnitude and direction of this cogging force would vary as a function of
shaft position.
Linear motors that use an iron core also exhibit cogging forces. The main difference between
rotary motors and linear motors is that in linear motors these forces are periodic as a function
of distance versus angle. In the linear motor, these forces tend to pull the vehicle forward or
backward at specified intervals along the motor.
The MagneMover LITE linear motors do not use an iron core. As such, they do not exhibit
any cogging forces.
Motor Blocks
A motor block is a discrete motor section within each MagneMover LITE motor or switch as
shown in Figure 6-2. Each block consists of an independently controlled inverter that drives
one copper winding, with multiple blocks creating the motor primary (stator). Since the motor
windings don’t have an iron core, there is no attractive force between the magnet array and
motor.
Block Acquisition
The controller for each motor takes ownership of vehicles (pucks) when they enter the motor
or are identified during startup and maintains that ownership the entire time the vehicle is on
the motor. Ownership includes identification of the final destination, maximum acceleration,
and maximum velocity as defined in the current motion order and determination of the interim
destination for the vehicle and current acceleration and velocity setpoints.
The controller makes sure that the vehicle has acquired sufficient empty blocks ahead of the
vehicle in the direction of motion to maintain brick-wall headway with the current motion
profile as shown in Figure 6-3. The vehicle is said to own these blocks until they are released.
Headway is maintained by communicating with the motors ahead of the vehicle to make sure
that sufficient blocks can be acquired to define new interim destinations.

Rockwell Automation MagneMotion MagneMover LITE Specifications

General

Brand	Rockwell Automation
Model	MagneMotion MagneMover LITE
Category	Accessories
Language	English