Theory of Operation
P/N 400274-01 Revision A7
15
Starting A Follower Cycle
An initial
Home
or
Index
is required to move the Follower axis to the
Follower zero position
before
the
Y Execute Follower Cycle
statement is
executed. This will determine, using the
Working Offset,
the position of
the
Cycle Point
on the product. When the
Y Execute Follower Cycle
statement is executed, the
Follower Cycle Defined
output function will
activate and if the Master cycle is defined, the Follower cycle will start.
When the PCM-22 axis starts moving from the Follower zero position,
Home
position or the
Cycle Drop Out Position
, a linear acceleration is
used to get to the correct velocity at the beginning of the
Working
Segment
. The PCM-22 checks the first product’s (
Cycle Point
) position to
see if it can reach the correct velocity (
Working Ratio
* Master velocity)
in the distance it would travel from the Follower zero position to the
beginning of the first product’s
Working Segment
. If this is not possible
(i.e., the start-up distance is longer than the first product position), the
PCM-22 will check the second product position. If it can not make the
second product position, it will check the third and so on, until the
PCM-22 finds a product position that will allow the Follower axis to
reach the product’s
Working Ratio
velocity at the beginning of its
Working Segment
. The Follower axis is not moving while it is
determining which product position to try for. See Figure 9 and
Master
Phase Distance
.
ZERO
MASTER
SENSOR
MASTER PHASE DISTANCE
ZERO FOLLOWER
SENSOR
WS
WORKING
OFFSET
DIRECTION OF FOLLOWER ROTATION
PRODUCT MOVEMENT
Figure 9 PCM-22 Starting Cycle Ramp
When the Follower has passed the
first
Cycle Point
after the Master has
moved the
Master Phase Distance
, the
In Phase
output function will
activate.
In
Master Cycle Defined By Sensor
mode, it is possible for the start-up
distance to be greater than the
Master Phase Distance
. If this is the case
it will generate product positions to target
before the sensor
using the
Average Master Length
. Please note that the entered
Master Cycle
Length
is only equal to the
Average Master Length
just after the Master
processing is reset.
The Follower will start executing the computed starting ramp distance to
the targeted product position. Any products that pass the
Cycle Point
before the Follower has completed the initial acceleration will be ignored.
See Figure 10,
Average Length
, and
Resetting the Master Processing
.