Appendix B
06/2005
Danaher Motion
174 Rev
E
M-SS-005-03
There are some properties that are axis- or group-only properties. For example
DRIVEADDRESS
is an axis-only property.
MOVE
consists two different command behaviors, Move-Group and Move-Axis. Move-
Group moves the whole group together. All the axes within the group start and end the
motion at the same time. Move-Group stays within the kinematics limits (
VELOCITY
,
ACCELERATION
,
JERK
) of the group and axes. The group limits are taken and imposed
on the group motion (aggregate, space – XY, XYZ). The axis limits are imposed only
proportionally to the ratio of the axis motion to the whole group motion. If axis X is moving
halfway toward axis Y, only half the limit values are used. The total time of the motion is the
time required for the slowest axis to accomplish the movement. Here, the slowest axis is the
one with the largest path/velocity ratio and not necessary the axis with smallest maximum
velocity (because if such an axis has no movement to make, it is not the slowest axis). On
the other hand, Move-Axis checks only the limits of the specified axis and is independent of
the limits of any group using this axis.
Profiler preparations can additionally reduce the motion parameter. This is typical for short
movements where the given cruise velocity cannot be reached due to existing limitations of
ACCELERATION
and
JERK
.
Joints
Joints are virtual axes. Joints give the illusion of only one axis, both from the language point
of view and looking at the physical movement of the coupled axis. The joint is analogous to
an axis. Joints are denoted as J1, J2, etc.
Each joint actually represents one or several axes of the group, according to the given
coupling matrix. If the group has no coupling matrix defined, the joint is a direct
representation of the axis of the same ordinal number in the group as the joint index. To
introduce another term, the "shadow-axis" of a joint is the axis with the same ordinal number
in the group as the joint index. For example, if a group consists of axes A2, A3, A4, the
shadow-axis of the joint J1 is A2.
Normally, all joint properties are a direct representation (have the same value) of shadow-
axis properties, independent of whether the coupling matrix is defined or not. The only
exceptions are properties related to joint position:
PCMD
,
PFB
,
VCMD
,
VFB
,
CCMD
,
CFB
,
PMAX
, and
PMIN
. These are unique for each joint.
Current positions and velocities are obtained according to the given coupling matrix. They
are computed each time a query of these values is issued (
PCMD
,
PFB
, etc.). They are
read-only and do not represent any specific internal variable. Symmetrically the same
properties, when queried from a group (
?g1.PCMD
), return lists of joint-property values
according to the coupling matrix. The movement’s target positions (
MOVE
or
CIRCLE
) of
group movements are treated analogously (coupling matrix).
On the other hand, the joint’s position limits (
PMAX
and
PMIN
) are added to the joints. The
position limit of the joint and the position limit of the shadow-axis are not related, but
independent of whether the coupling matrix is defined or not. The joint position limits are
always used when the coupling matrix is defined (
COUPLED = 1
). In this case, the shadow-
axis limits are not used. This is only true for joint and group movements. Single-axis
movement (e.g.,
MOVE A1 100
) is limited only by the axis limits, independent of coupling.
Joints represent several axes of a group. Joint movements are actually group movements:
Move-Group = Move-Joint
