General Motion Specifications Menu
The general motion specifications establish the motion speed and acceleration limits as well as the start-up values for these parameters. The maximum allowable values help prevent users from placing excessive demands on the system. The default start-up values allow you to control accelerations and acceleration profiles used until user override.
When you select a menu option, the following information is provided on screen:
Instructions for the specified option
Current value
Value range for the parameter if applicable
For details on a menu option, click the desired link in the following list to view the description:
Maximum allowable acceleration
Maximum allowable deceleration
Maximum allowable program speed
Maximum rate of change of monitor speed
Minimum execution time for joint motions
Minimum execution time for Cartesian motions
Default S-curve profile at system startup
Default acceleration at system startup
Menu Options
Maximum allowable acceleration
Limits the maximum percent acceleration that the user is allowed to specify via the ACCEL instruction. Normally, this limit is set to 100%. However, there may be instances where 100% is routinely specified within robot programs, but higher values are permitted for special circumstances.
Maximum allowable deceleration
Limits the maximum deceleration that the user is allowed to specify via the ACCEL instruction. Normally, this limit is set to 100%. However, there may be instances where 100% is routinely specified within robot programs, but higher values are permitted for special circumstances.
Maximum allowable program speed
Limits the maximum % speed that the user is able to specify via the SPEED program instruction (the SPEED monitor command is always limited to 100%). Given that the inertia of the robot is usually quite variable, the maximum %speed is normally set well above 100%.
Max rate of change of monitor speed
During the execution of a robot program, the monitor SPEED command can be used to change the overall speed of robot motions. This change takes affect immediately, even if the robot is currently executing a motion. To limit the acceleration jerk that the robot would experience if a large change in speed was applied instantaneously, any requested monitor SPEED change is distributed over several trajectory evaluation cycles. This parameter specifies the rate at which changes in the monitor SPEED are applied to the robot. For instance, if a value of 20 is specified, it would take 3 seconds for a change from SPEED 40 to SPEED 100 to be fully applied.
Minimum execution time for joint motions
The minimum motion execution times should be set long enough to provide adequate time for the motion planner to plan the next motion before the current motion completes execution. If these values are too short, CP will break unnecessarily. If these values are too long, quick, high speed motions will not be possible. In essence, these values define the lower limit for the DURATION instruction for the current robot. As a convenience, if these values are set to 0, the minimum motion time will be set equal to the configured V+ trajectory cycle time.
Minimum execution for Cartesian motions
The minimum motion execution times should be set long enough to provide adequate time for the motion planner to plan the next motion before the current motion completes execution. If these values are too short, CP will break unnecessarily. If these values are too long, quick, high speed motions will not be possible. In essence, these values define the lower limit for the DURATION instruction for the current robot. As a convenience, if these values are set to 0, the minimum motion time will be set equal to the configured V+ trajectory cycle time.
Default S-curve profile at system startup
Specifies the S-curve trajectory profile that will be selected by default when the controller is first booted. If the specified profile is not defined, profile 0 (a square wave acceleration) will be selected.
Default acceleration at system startup
This value specifies the default % acceleration that will be asserted when the controller is first booted.
Default deceleration at system startup
Specifies the default % deceleration that will be asserted when the controller is first booted.
Default BASE offsets
Specifies the default BASE transform used to modify the base transformation. That transformation is used to offset the world reference frame relative to the X/Y/Z coordinate system, and rotate the world reference frame about the Z axis.
Normally, the default BASE offsets are set to 0 and the world reference frame is assumed to be fixed in space such that the X-Y plane is at the robot mounting surface, the positive X axis points along the center of joint 1 when at zero degrees (or millimeters) and the Z axis coincides with the joint-1 axis. For additional information, see the BASE monitor command and the BASE program instruction.
Upper Speed Limit for SCALE.ACCEL
Defines the limit below which SCALE.ACCEL scales motion acceleration and deceleration values in proportion to the program speed. For example, if this value is set to 100% and a program speed of 50% is specified, the desired acceleration and deceleration will be internally set to half of what the user has specified. But, if the program speed is higher than 100%, the user specified acceleration and deceleration will be used without modification.
If the SCALE.ACCEL limit value is set to a large number, SCALE.ACCEL will always scale the acceleration and deceleration. For example, in this case, a speed of 200% would double the commanded acceleration and deceleration.
Note: This parameter can also be edited in the restricted-access mode of SPEC, as described in Instructions for Adept Utility Programs.)