User`s guide

172 Adept Cobra PLC600/PLC800 Robot User’s Guide, Rev C
Approach and Depart
When approach and depart heights are specified, the robot moves in three distinct
motions. In the first motion (approach), the robot moves to a location directly above the
specified location. The height above the location is specified in N30:7 or
Adept_Approach_Height (see page 85). For the second motion, N30:7 or
Adept_Approach_Height is set to zero, and the robot moves to the actual location and the
gripper is activated. In the third motion (depart), the robot moves to a point directly above
the location. The depart motion uses the height specified by N30:7 or
Adept_Approach_Height.
Approach and depart heights are used to make sure that the robot approaches and
departs from a location without running into any other parts in the assembly being built
(or any other obstructions in the robot envelope). Approaches and departs are always
parallel to the Z-axis of the tool coordinate system. Notice that all the motion parameters
that apply to a motion to a location also can be applied to approach and depart motions.
This allows you to move at optimum speed to the approach height above a location, then
move more slowly when actually acquiring or placing the part, and finally depart quickly.
NOTE: Each of the three motions -- approach, move-to, depart -- must be
commanded separately by the PLC
Arm Configuration
Another motion characteristic that you can control is the configuration of the robot arm
when moving to a location. However, configuration options apply only to specific types of
robots. For example, the lefty/righty option applies to SCARA-type robots (such as the
Adept Cobra PLC), but the above/below option does not apply to those robots.
Figure 10-1 shows how a SCARA robot can reach a point with the elbow pointing in two
different directions. The Lefty/Righty arm configuration is specified in N30:3/13 or
Adept_Motion_Qualifier.13.
NOTE: Other arm configuration bits are supported by the PLC Server (see
N30:3/13-15 or Adept_Motion_Qualifier.13-15). However, only the
lefty/righty bit applies to a SCARA robot, such as the Cobra PLC robot.