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Using the KS Command (Step Motor Smoothing):
When operating with step motors, motion smoothing can be accomplished with the command, KS.
The
KS
command smoothes the frequency of step motor pulses. Similar to the command IT, this
produces a smooth velocity profile.
The smoothing parameter used is a number between 0.5 and 128 and determines the degree of filtering. The
minimum value of 0.5 implies the least filtering, resulting in trapezoidal velocity profiles. Larger values of the
smoothing parameters imply heavier filtering and smoother moves.
Homing
The Find Edge (FE) and Home (HM) instructions may be used to home the motor to a mechanical reference. This
reference is connected to the Home input line. The
addition to the Home input. The configure command (CN) is used to define the polarity of the home input.
The Find Edge (FE) instruction is useful for initializing the motor to a home switch. The home switch is connected
to the Homing Input. When the Find Edge command and Begin is used, the motor will accelerate up to the slew
speed and slew until a transition is detected on the Homing line. The motor will then decelerate to a stop. A high
deceleration value must be input before the find edge command is issued for the motor to decelerate rapidly after
sensing the home switch. The Home (HM) command can be used to position the motor on the index pulse after the
home switch is detected. This allows for finer positioning on initialization. The
causes the following sequence of events to occur.
Stage 1:
Upon begin, the motor accelerates to the slew speed specified by the
motion is determined by the state of the homing input. If
direction first (direction of decreasing encoder counts). If
direction first.
is the command used to define the polarity of the home input. With
CN
switch will make
_HMA
a normally open switch will make
CN,1
Therefore, the
command will need to be configured properly to ensure the correct direction of motion in the
CN
home sequence.
Upon detecting the home switch changing state, the motor begins decelerating to a stop.
NOTE: The direction of motion for the
Stage 2:
The motor then traverses at
If Stage 3 is in the opposite direction of Stage 2, the motor will stop immediately at this point and change direction.
If Stage 2 is in the same direction as Stage 3, the motor will never stop, but will smoothly continue into Stage 3.
Stage 3:
The motor traverses forward at
decelerates to a stop and goes back to the index.
The DMC-21x5 defines the home position as the position at which the index was detected and sets the encoder
reading at this point to zero.
The 4 different motion possibilities for the home sequence are shown in the following table.
Chapter 6 Programming Motion ▫ 75
read 1 initially, and a normally closed switch will make
read 0 initially, and a normally closed switch will make
_HMA
command also follows these rules for the state of the home input.
FE
counts/sec in the opposite direction of Stage 1 until the home switch toggles again.
HV
counts/sec until the encoder index pulse is detected. The motor then
HV
command initializes the motor to the encoder index pulse in
HM
or
JG
SP
reads 1 initially, the motor will go in the reverse
_HMA
reads 0 initially, the motor will go in the forward
_HMA
command and
command
HM
BG
commands. The direction of its
, a normally open
CN,-1
read 0. Furthermore, with
_HMA
_HMA
DMC-21x5 User Manual 1.0a1
read 1.
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