Manual

Detailed Descriptions of ACL Commands 3-9
Errors
If a command not on the above list is encountered; or if an otherwise legal command causes
an error such as a bad parameter, wrong number of parameters, or a travel limits violation; or
if the 201st physical action command is encountered: the bad command is not executed.
Instead, the error is logged and all remaining physical action commands until the EC are
ignored. Then the System executes those physical action commands which preceded the bad
command, plus all non-action commands.
Acceleration and Step Rate
The System uses the acceleration specified by the most recent AC command, and the step
rate specified by the most recent SR command. (Any AC or SR command must occur
before the BC command in order to affect Continuous Path motion.)
However, the VM command may cause the System to use the alternate acceleration and step
rate. (Such a VM must occur before the BC command.) See personality parameters 34 and
35 in Chapter 7.
If a given BC...EC sequence contains any arcs, the acceleration is set to 0.707 of the
specified value, in order to "budget" radial and tangential acceleration. Also, the slew speed
may be decreased according to the smallest arc radius in the sequence, in order to limit radial
acceleration. See the discussion under the AA command. The maximum achievable step
rate for a Continuous Path with arcs is approximately 16000 microsteps per second.
If the BC...EC sequence contains no arcs, the specified acceleration and step rate values are
used, as-is. The maximum step rate without arcs can be as high as 65535 microsteps per
second under some conditions; see below.
The step rate is limited to lower values if certain microstep factors have been specified; see
the RE command. If the SR command specifies a higher step rate, the System uses the
highest achievable rate.
If the step rate has been set higher than about 2100 microsteps per second, or if the overall
length of the BC...EC sequence is more than 65535 microsteps, the System automatically
skips some intermediate microstep positions during the Continuous Path motion. This
skipping is done in a regular, smooth pattern and does not affect the overall motion.
However, it does affect the dynamic resolution and the accuracy with which the "ideal"
endpoint can be reached. Available motor torque may be reduced.
The sequence should not contain more than one or two CD, TD, or SP commands between
any given two vectors or arcs. The System takes a small amount of time to execute the CD,
TD, or SP; if too many are executed all at once, there will be an extra-large delay between
two microsteps, and the motors may slip.