Emerson EZMotion - Index; Absolute Index

Safety
Information
Introduction Installation
PowerTools
Pro Software
Communications
How
Motion
Works
How I/O
Works
Configuring
an
Application
Programming
Starting and
Stopping
Motion
Starting and
Stopping
Programs
Parameter
Descriptions
Drive
Parameters
Used by
EZMotion
Diagnostics Glossary Index
EZMotion User/Programming Guide 37
Revision A8 www.controltechniques.com
Figure 42: Home to Sensor (Back Off Before Homing)
Go Forward To Next Sensor
On some machines, motion in a certain direction may be prohibited due to mechanical design. In this case, the Back Off
Before Homing option may not be practical. In this case, if the Home Sensor is active when the Home is initiated, the motor
continues in the programmed direction until the next "Rising Edge" of the external home sensor is detected. Figure 43 shows
the Home to Sensor profile when the Home Sensor is active when home is initiated and Go Forward To Next Sensor is
selected.
Figure 43: Home to Sensor (Go Forward To Next Sensor)
6.3 Index
An Index profile is used to move the motor a precise distance or to a specific position. There are many different applications
that can be solved using different combinations of Index types. The five major types of Indexes are Absolute, Incremental,
Registration, Rotary Plus, and Rotary Minus. Each of these Index types are described in detail below.
6.3.1 Absolute Index
An Absolute Index is used to move the motor to a specific position. After completing an Absolute Index, the motor will always
be in the same position regardless of the starting position of the motor. The direction that the motor moves during an Absolute
Index is dependant upon its position when the index is initiated.
If an Absolute Index is initiated a second time, just after completing the first index the motor will not move because it is already
at its specified absolute position.
Figures 44 and 45 show examples of an Absolute Index profile.
Figure 44: Absolute Index Profile (Example 1)
Velocity
Home Accel
Home Velocity
Home Decel
Time
Home Accel
Home Initiate
External Home Sensor
Home Decel
Home Velocity
External Home
Sensor Clears
+
-
Home Sensor is active when
Home is initiated, so motor
travels in negative direction
Velocity
Home Accel
Home Velocity
Home Decel
Time
Home Initiate
External Home Sensor
First rising edge is used as Home reference
-2-4 -1 0 421
Starting Position: -2 Revs
In
de
x P
os
iti
o
n: 2 R
e
v
s
Position
(Revs)