Emerson FM-3 - Manual (Page 35)

21
Operational Overview
Absolute indexes with Rotary Rollover enabled will take the shortest path to the position
entered in the index position parameter.
Note
Absolute indexes move to positions relative to where the machine was homed using the
Home, or the DefineHome destination.
Incremental Indexes
An incremental index will move the motor a specified distance in the + or - direction
regardless of the starting position. The direction of the incremental index motion is
determined by the sign (+ or -) of the Index Distance parameter.
Incremental Index
Figure 25: Incremental Index Example
In the example above, the motor starts at 1 rev, travels a distance of 2 revs and stops at 3 revs.
If the same index is initiated a second time, the FM-3 module would move the motor another
2 revs to a position of 5 revs. If initiated a third time, the motor would travel another 2 revs
to a final position of 7 revs. The example below shows this operation.
Figure 26: Incremental Index Example 2
Incremental Index
Start Position = 1 Rev
Index Distance = 2 Revs
Incremental Index
Start Position = 1 Rev
Index Distance = 2 Revs