PCM-22 Rotary Knife Controller
16
© EMERSON Motion Control
CAN
MAKE
IT
ZERO MASTER
SENSOR
WS
WORKING
OFFSET
DIRECTION
OF ROTATION
CAN NOT
MAKE IT
ZERO FOLLOWER
SENSOR
PRODUCT MOVEMENT
AVERAGE
MASTER
LENGTH
Figure 10
When the Follower Start-up Ramp Exceeds the Master Sensor Distance
Homes and the Follower Zero Position
In order to obtain the highest accuracy, certain types of homes are
recommended for use with the PCM-22:
Resolver Offset
and
Feed On/Off.
Make sure the “On” move is in the direction of travel and
the “Off” move is much slower in the opposite direction. The goal of this
is to have the Follower’s starting position be the same as the Follower
zero position when the cycle is running. A reducer’s backlash is minimal
compared to an inaccurate initial reference position during the first
several cycles.
Ensuring a correct starting position goes far in eliminating length and
phase variations when the Follower is executing its first several cycles
and learning its length the fastest.
It is not recommended, but it is possible, once the home is completed, to
move to a different location which will be the Follower zero position. It is
from this point that the Follower cycle will start. If this is not the actual
Follower zero position and the Follower cycle is defined by sensor, the
PCM-22 will perceive this as an error and correct for it.
Indexes and the Follower Zero Position
An index may be used instead of a home to move the Follower axis to
the Follower zero reference position. It behaves the same as a home but
there are more options for positioning the Follower axis before actually
starting the cycle.
For example:
•
A
Registration
index.
•
A
Feed to Sensor
index.
•
A home followed by an
Incremental
index.
The index must not be compounded and must finish before the Follower
cycle begins.
Ensuring a correct starting position goes far in eliminating length and
phase variations when the Follower is executing its first several cycles
and learning its length the fastest.
