ElmoMC Multi-Axis Motion Controller-Maestro Motion Control - Manual (Page 5)

general trajectory time (vtt)
switch arc definitions (vsc, vsr, vsd)
admissible velocity and position errors definitions (vpe,vve)
PVT step low and high limits (VNT,VXT )
All of the vector’s properties can be set in a user program or by the Command Interpreter.
Syntax of a property:
Vector_name.property
Examples:
v1.vsp - defines maximum vector velocity
v1.vtt - defines trajectory time
v1.vsc - defines smooth type from one shape to another
(1 – minimal radius switch arc, 2 – fixed radius switch arc, 3 – switch with a fixed distance from
the intersection point).
Single shape trajectories can be executed in one of three modes pre-defined by the value of the
input parameter vum: 1 – max velocity, 2 – fixed time, 3 – fixed velocity.
In the maximum velocity mode, velocity defined by the parameter vsp is considered a limiting
value that cannot be exceeded. If a trajectory is not long enough to achieve such a value, then a
trajectory with a triangle velocity profile is built and some maximum vector velocity
V
max
< vsp
is achieved at one point.
The fixed velocity mode (vum=3) is used if the user is interested in building a trajectory with a
trapezium velocity profile – the main part of the trajectory (with the exception of possible
acceleration/deceleration at the initial and final parts of the trajectory) is executed with a velocity
equal to vsp. If a trajectory is not long enough to reach velocity vsp with the given vector
acceleration /deceleration (input parameters vac/vdc), the trajectory is not built and the user
receives an error message.
In the fixed time mode (vum = 2) the user must define parameter vtt – time in milliseconds for the
trajectory execution. The Motion Library chooses a velocity profile that satisfies parameter vtt. If a
trajectory with the given length, maximum velocity vsp and vector acceleration/deceleration
cannot be executed within time vtt trajectory is not built and the user receives an error message.
The user can set values for the maximum PVT step in milliseconds – parameter vxt and for the
minimal PVT step – parameter vnt ≥ 1msec. In this case, the main part of the trajectory will be
executed with the PVT step
ΔT
= 0.5(vxt + vnt) .
For the switch arc, connecting two shapes can be chosen from one of the three possible modes pre-
defined by the input parameter vsc: 0 – no switch arc to be built, 1 – switch arc with the minimal
possible radius, 2 – switch arc with radius pre-defined by the user, 3 – user defined distance from
the intersection point (for the line-line or circle-line intersections).
Maestro Motion Library Tutorial
MAN-INTUG (Ver. 1.7)
2