Downstream Gap; Motor Cogging; Motor Controllers - Rockwell Automation MagneMotion MagneMover LITE Original Instructions Manual

Downstream Gap

An additional measurement between motors is the distance from the last block of the stator in
one motor to the first block of the stator in the next motor downstream. This space is referred
to as the downstream gap (shown in
Motor Gap plus 2 mm.
NOTE: It is recommended that the maximum downstream gap between motors is 10% of the
magnet array length. When a dual array vehicle is used, the maximum downstream
gap is 10% of the length of one of the arrays. Larger gaps are possible, but cause
greater loss of thrust. Contact your Motion Solutions Consultant or Technical Sup-
port (see
The downstream gap affects the force available for vehicle motion between motors. There is a
certain amount of thrust available per magnet array, providing that the magnet array is located
above the motor (magnet array coverage). There must be enough thrust to move the vehicle
past the gap between motors. Do not locate process stations within the gap between motors as
settling time and repeatability are negatively affected. Locating the process stations in curves
and switches is not recommended as thrust and repeatability are negatively affected.
NOTE: The MagneMover LITE motors do not compensate for the amount of thrust that is
lost when the magnet array is over the downstream gap. This means that if the array
only has half coverage the effective PID values and peak thrust are halved and the
system does not perform as well as with full coverage.
It is important to note that the downstream gap measurement is added to the last motor block
of all MagneMover LITE motors in the transport system. This gap value is important when
considering the motor blocks that a vehicle (puck) owns (see
The gap value is also used for determining when vehicles are considered to be at the end of a
path or cleared of a node boundary (such as a Terminus Node).

Motor Cogging

Due to the use of an epoxy core for the motor windings, there is no cogging between the Mag-
neMover LITE motor and the magnet array (see

Motor Controllers

The motor controller for each MagneMover LITE motor is located inside the MM LITE
motor. Each MM LITE motor has one motor controller.
The motor controller is responsible for controlling the thrust that is applied to each vehicle
(puck) by the motor and reading the sensors in the motor to determine vehicle position. The
motor controllers communicate with each other and a node controller via either RS-422 or
Ethernet.
MagneMover LITE User Manual
Figure
Rockwell Automation Support on page
Rockwell Automation Publication MMI-UM002F-EN-P - October 2022
3-7). The downstream gap is equivalent to the
486) for additional information.
Block Acquisition on page
Motor Cogging on page
Design Guidelines
Transport System Design
319).
319).
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