Appendix A
8 9
Step 11
When we raised the
SGV
gain to 2.52, the
step response became fast and very stable.
SGP = 70
SGV = 2.52
Target Zone (Move Completion Criteria)
Under default operation (Target Zone Mode not
enabled), the APEX615n’s move completion
criteria is simply derived from the move
trajectory. The APEX615n considers the
current preset move to be complete when the
commanded trajectory has reached the desired
target position; after that, subsequent
commands/moves can be executed for that same
axis. Consequently, the next move or external
operation can begin before the actual position
has settled to the commanded position (see
diagram).
Position
Time
Velocity
Commanded
Actual
Actual
Commanded
Time
When the Target Zone Mode
is not enabled, the move is
considered to be complete
and subsequent moves can
be executed at this point in
time.
Move is actually
Completed
Target Zone Mode
To prevent premature command execution before the actual position settles into the
commanded position, use the Target Zone Mode. In this mode, enabled with the
STRGTE
command, the move cannot be considered complete until the actual position and actual
velocity are within the target zone (that is, within the distance zone defined by
STRGTD
and
less than or equal to the velocity defined by
STRGTV
). If the load does not settle into the
target zone before the timeout period set with the
STRGTT
command, the APEX615n detects a
timeout error (see illustration below).
Refer to the Error
Handling
section in
the 6000 Series
Software Reference
for error program
examples
If the timeout error occurs, you can prevent subsequent command/move execution only if you
enable the
ERROR
command to continually check for this error condition, and when it occurs
to branch to a programmed response you can define in the
ERRORP
program.
As an example, setting the distance zone to
±
5 steps (
STRGTD5
), the velocity zone to
≤
0.5
rps (
STRGTVØ.5
), and the timeout period to 1/2 second (
STRGTT5ØØ
), a move with a
distance of 8,000 steps (
D8ØØØ
) must end up between position 7,995 and 8,005 and settle
down to
≤
0.5 rps within 500 ms (1/2 second) after the commanded profile is complete.
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