Mitsubishi Electric D75D4, User Manual

Page: 842 / 896

Appendix - 126
MELSEC-Q
APPENDICES
AUTO TUNING (Automatic Tuning)
Properties such as responsiveness and
stability of machines driven with a servomotor
are affected by changes in the inertia moment
and rigidity due to changes in the machine
load, etc.
This function automatically adjusts the speed
loop gain and position loop gain to match the
machine state, so the machine's performance
can be maintained at its optimum state.
A real time automatic tuning function should be
used for machines having large load
fluctuations.
BACKLASH COMPENSATION
When a forward run operation changes to a
reverse run operation, there is sometimes play
(backlash) in the mesh of the toothed gears.
This also occurs when using a worm gear.
Because of this backlash, a left feed of 1m
carried out after a right feed of 1m will not be
sufficient to return the machine to its original
position. The machine cannot be positioned to
its original position without an extra feed
equivalent to the backlash amount. This
function compensates for that backlash
amount.
Backlash
Forward run
BACKUP FUNCTION
Backup functions consist of the following.
1) Functions for storing the sequence program
and device statuses stored in the RAM
memory of the CPU module, so that they
are not lost during power failures, etc.
2) Functions for storing the current value in
absolute position compatible systems so
that it is not lost during power failures, etc.
3) Functions for reading the CPU module data
(programmable controller programs,
parameters, positioning data, etc.) by a
peripheral device when the old CPU
module is replaced, and then write it to the
new CPU module after the replacement is
completed.
BALL SCREW
This is a type of screw, with balls lined up in
the threads like ball bearings. This reduces
backlash, and enables rotation with little force.
Female thread
Male thread
BIAS SPEED AT START
A large amount of torque is required when the
machine starts moving, but the torque may be
unstable at speed 0 with stepping motors.
Therefore, movement can be smoothly carried
out by starting the movement at a given speed
from the beginning. The bias speed at start is
the speed set at that start.
Full speed
Speed 0
Bias speed