Technical Reference
Motion Programming
www.galilmc.com
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Galil Motion Control, Inc.
9
Trippoints
Another function of advanced motion controllers is to schedule or
sequence events in a program.These functions are scheduled by
delaying the execution of each function until a certain condition
occurs.These conditions are called trippoints.
For example, the "After Distance"(AD) trippoint delays the execu-
Consider the motion cycle illustrated below.A forward motion of 10,000
counts must start upon a pulse on input #1.The initial velocity, acceleration,
and deceleration rates equal 20,000, 100,000, and 100,000 respectively.
After the motor has moved a distance of 6000 counts, the controller
starts a deceleration toward a speed of 10,000 counts/sec.That speed is
maintained for the rest of the move. Upon completion of the motion,
the controller waits 100 milliseconds before returning the motor to the
starting position, at a speed of 20,000 counts/sec. Once there, the con-
troller is ready to repeat the cycle.
Notice that the scheduling of the various functions requires the use
of trippoints.The start of the motion is delayed by the trippoint AI 1.
When the motion starts, the velocity change is scheduled with the trip-
point AD 6000.The controller must then wait until the completion of
the move (AMX) and adds a pure delay of 100 ms (WT 100) before
returning the motor to the starting position.The instruction program
and resulting flow chart follow.
INSTRUCTION
INTERPRETATION
#CYCLE
Label
PR 10000
Distance
SP 20000
Initial speed
AC 100000
Acceleration rate
DC 100000
Deceleration rate
AI1
Wait for start pulse
BGX
Start motion
AD 6000
Wait until X moves 6000 counts
SP 10000
Change the speed
AMX
Wait for completion of move
WT 100
Wait 100 msec
PR -10000
Reverse motion
SP 20000
Return speed
BGX
Start motion
AMX
Wait for end of motion
JP#CYCLE
Repeat the cycle
EN
End
Example--Motion Cycle using Trippoints
INPUT 1
TIME
TIME
-20000
20000
10000
VELOCITY
Flowchart for #Cycle
AFTER A DISTANCE
OF 6000 COUNTS
SPEED=10000
WHEN MOTION IS COMPLETE WAIT 100 ms
MOVE BACK 10000
AT SPEED 20000
DISTANCE=10000
SPEED=20000
WAIT FOR INPUT 1
START THE MOTION
CYCLE
WHEN MOTION IS COMPLETE
tion of a function until after the motor moves a certain distance.
Similarly, the execution of a function can be delayed until a move
has been completed (AM), an input signal changed states (AI), or by
a pure time delay (WT).
The following example illustrates the use of trippoints in execut-
ing a motion cycle.
