Rockwell Automation GMLC Reference Manual - Manual (Page 163)

Publication GMLC-5.2 - November 1999
126 Using the Imaginary Axis
When used with an imaginary axis, both of the following blocks, use the
command position (versus the actual position) of the imaginary axis’:
• Watch Control - Arm Watch Position block
• On Watch - Wait for Position Event block
This is because the imaginary axis has no actual position. By contrast,
when used on servo and master-only axes, these blocks use the axis’
actual position.
While all of the appropriate motion status variables (Jog_status,
Accel_status, etc.) apply also to the imaginary axis, the imaginary axis
never indicates an axis locked status. Thus Lock_status for the imaginary
axis is always 0 (Unlocked) and Axis_status is always greater than 0.
The normal axis status for an enabled imaginary axis with no commanded
motion is unlocked (Axis_status = 1). In addition, no axis faults are ever
active for the imaginary axis. Thus Axis_fault and the other axis-specific
fault variables are always 0 for this axis. Average_Velocity for an
imaginary axis is always zero. Use Command_Velocity for the velocity of
an imaginary axis. See the System Variables chapter in this manual for
more information on these variables.