96-8000 395
OPTIONS
June 1999
SETTING U P A F IFTH A XIS
Installing a fifth axis is the same as installing a fourth axis. Refer to the "Setting Up A Fourth Axis" section of
this manual for detailed instructions on fifth axis installation.
AUTOMATIC A CCELERATION/DECELERATION
This machine is not capable of instantly changing speed; it takes some nonzero time to accelerate and
decelerate. Acceleration and deceleration in this machine have both a constant accel/decel mode and an
exponential mode. Constant acceleration is used at the beginning of a rapid move and at the end of any move
whose speed exceeds the exponential accel/decel time constant.
CONSTANT A CCELERATION
Constant acceleration is a type of motion when the amount of speed change over time is constant. This
constant is set by Parameters 7, 21, 35, and 49. It has units of encoder increments per second per second.
Constant acceleration applies to the beginning of a rapid move so that the minimum time is spent getting up to
rapid speed. It also applies to the end of rapid moves until the speed drops below the exponential accel/decel
time constant. That change occurs at about 129.7 inches per minute in the following example.
EXPONENTIAL A CCELERATION
Exponential acceleration/deceleration is a type of motion where the speed is proportional to the distance
remaining in a programmed travel. The exponential accel/decel time constant is set by Parameters 113, 114,
115, and 116. It has units of 0.0001 seconds. The speed limit at which exponential accel/decel is not available
is defined by the relationship between Parameters 7 and 113 (for the X-axis). Thus, if Parameter 7 is 8000000
steps/sec/sec and Parameter 113 is 375 (0.0375 seconds); the maximum velocity for exponential accel/decel
would be:
8000000 x 0.0375 = 300000 steps/second
For a 8192 line encoder and 6 mm screw, this would be:
60 x 300000 /138718 = 129.7 inches/minute
ACCELERATION IN F EED M OTIONS
In the normal feed cutting mode, with G64 active, giving continuous cutter motion, deceleration of the axes in
motion begins at some distance away from the end point. If lookahead has buffered another motion, the
acceleration for that motion will begin at the same instant. This means that two motions, at right angles to
each other, will not produce a perfectly square corner. The corner will be rounded. In addition, two motions
which smoothly blend one into the other will not cause the tool to pause.
If you use cutter compensation to cut an outside corner, there will be no rounding if the cutter compensation
amount is close to the actual tool size. This is because the tool is moved beyond the end of the first pro-
grammed stroke before it is moved to the beginning of the second stroke. Note that in this machine, using the
default parameter settings, rapid and feed moves will both be blended to provide continuous cutter path and
rounded corners. Unless you specify exact stop, the following rapid or feed block will be started slightly before
the completion of the previous block.
To Next Page
Loading...
Need help?
General
