2
SYSTEM
CONFIGURATION
/MELSEC-A
The system can be zeroed in one of three
weys.
All
use
a
"zeroing
dog." The "zeroing dog"
is
a
switch
or
actuator which provides one
of
two
conditions which define the home position.
The
second
condition depends on the zeroing method used, this will be one of
the following:
0
A
zero phase signal from the rotary encoder.
0
A
mechanical stop followed by
a
timer timingout.
0
A
mechanical stop followed by
a
torque feedback signal from the
drive unit.
The operating data for the
AD71
is
stored in the buffer memory and
consists
of
parameters (defining system constants such
as
maximum
feedrates,
etc.),
zeroing data (defining the zeroing process), posi-
tioning data (containing the individual addresses,
speeds,
etc.) and
start
data (defining which position to
start
at,
etc.).
Positioning data
is
referred to by
a
positioning data number, which
is
defined by
its
location in the buffer memory.
There are
two
methods for manual control of the
AD71
pulse chain
output, these are jog operation and inching. During jog operation,
the output pulse chain
is
maintained for
as
long
as
the
jog signal from
the
PC
is
on however during inching
a
defined number of pulses
is
output every time
a
manual pulse generator input signal
is
given.
(The manual pulse generator
is
also referred to
as
"manual pulser").
The inching function therefore requires the provision of an external
manual pulse generator hard wired to the
AD71
connector in order
to operate effectively.
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