www.galilmc.com
/
Galil Motion Control, Inc.
11
CONTROLLERS
--
INTRO
General Description
Galil Controllers
Contouring
The contouring mode (CM) is extremely flexible as it allows any
arbitrary profile on any set of axes to be prescribed. Here, the user
bypasses the controller profiler and directly inputs the position versus
time trajectory.The trajectory is described as the position increment
(CD) over a defined time period (DT). Additionally, the controller per-
forms linear interpolation between prescribed points.The contour mode
is useful for following complex, computer-generated paths or for "teach-
ing" position paths. An automatic data-recording feature allows the con-
troller to "learn" a path and then follow it in the contour mode.
Generate an XY motion according to a file of points
specifying the position increments every 16 msec.To
simplify the example, it is assumed that only 4 segments are required.
An array is used for each axis.
Segment
DX
DY
1
40
40
2
100
20
3
80
-40
4
40
-20
PROGRAM
INTERPRETATION
#D
DM DX[4],DY[4]
Define arrays
DX [0]=40;DY[0]=40
DX [1]=100;DY[1]=20
DX [2]=80;DY[2]=-40
DX [3]=40;DY[3]=-20
CM XY
Specify contour
DT4; P=0
Time interval
#LOOP
Loop
CD DX[P],DY[P]
Specify contour data
P=P+1
Increment counter
WC
Wait to complete
JP#LOOP, P<4
Loop until done
CD 0,0
Contour data for end
DT0
Set time interval to 0 to end mode
EN
End program
Example--Contouring
Electronic Cam
Any slave axis or set of slave axes can be linked to a master axis to
simulate the motion of a mechanical Cam. Here, the master axis can be a
motor-driven axis or a master encoder.The Cam functions are specified
by a table that allows complex profiles with varying gear ratios to be pre-
scribed. Any follower axis may be engaged or disengaged independently
at specific points along a Cam cycle.This allows the selecting of the
engagement and disengagement points as those where the speed
change of the follower is minimal.The electronic Cam is an ideal mode
for periodic operation, especially those requiring a varying gear ratio
along the motion cycle. Applications include flying shears, rotating
knives, and packaging systems. Galil's Cam-generating software can
assist the user to define the Cam table.
I/O
Error Handling
Dedicated I/O is provided for the following safety controls: forward
and reverse limit inputs for each axis, home inputs for each axis, amplifier
enable outputs for each axis, configurable abort inputs for each axis,
master abort input, and error output. Also, the controller provides the
following safety functions in software: upper and lower software travel
limits, position error limits, and automatic shut-off on excess position
error. Program interrupts are provided for error and limit conditions and
run-time program errors.The program interrupts cause the program
sequencer to automatically branch to an error handling subroutine.
In order to provide flexibility and system protection, the error handling
subroutine can be customized by the user.
User I/O
In addition to dedicated inputs for home and limits, Galil controllers
provide user I/O for synchronizing motion with external events such
as switches and relays.The DMC-18x0 controller, for example, includes
8 analog inputs, 8 digital inputs and 8 digital outputs for 1 to 4-axis
models; and 8 analog inputs, 24 inputs and 16 outputs for 58 axis
models. All Galil controllers include many commands for handling I/O
such as input interrupts, I/O triggers and timers.The combination of user
I/O and application programming often eliminates the need for a PLC.
As part of the user I/O, Galil controllers provide a high-speed position
capture or position compare feature for each axis.The high-speed posi-
tion capture latches the exact position within .1 microsecond of the
occurrence of an input. Position capture is crucial for applications requir-
ing precise synchronization of position to external events such as coordi-
nate measurement machines. The high-speed position compare feature
produces an output pulse at a precise position.The starting position for
the initial pulse and incremental distance for subsequent pulses are pro-
grammable.The accuracy allows for triggering external events to exact
positions within .1 microseconds.
