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Operation
Theory of Operation
MagneMover LITE User Manual 7
Rockwell Automation Publication MMI-UM002E-EN-P - March 2016
motors will reach a thermal limit and shut down. This tight spacing may be done on occasion
but it should not be a standard part of a process.
Safe Stopping Distance Movement
Standard vehicle control ensures vehicles (pucks) always have a safe stopping distance
(brick-wall headway).
Figure 6-4 shows acceleration, velocity, and position versus time for
the standard vehicle movement profile. Movement permission for a vehicle is granted as
needed to keep a vehicle on its movement profile (solid heavy line) and provide a safe stop-
ping distance (dashed heavy line) based on the vehicle's current velocity and commanded
acceleration. This can be found by dividing the square of a vehicle’s current velocity by twice
its acceleration (V
2
/2a).
Figure 6-4: Vehicle Movement Profile
In Queue
Typically, the vehicles (pucks) will queue up while in route to a particular destination when
another vehicle obstructs or jams the route. Obstructions are normal occurrences, jams are not.
While in queue, the vehicles can be as close together as permitted by the system and the
amount of space in between the carriers mounted on the vehicles depends on the defined
length of the vehicle. All of the vehicles in the queue will report being obstructed.
Destination
Vlimit
-Alimit
+Alimit
Time
Time
Time
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