Preface 
 
  Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018  25 
If the controller:  Then: 
Does not detect an error when the 
instruction executes 
The controller sets the .DN bit. 
Detects an error when the instruction 
executes 
The controller sets the .ER bit and stores an 
error code in the control structure. 
7.  The next time the rung becomes false after either the .DN or .ER bit sets, 
the controller clears the .EN bit. 
8.  When the rung becomes true, the controller can execute the instruction 
again. 
 
See also 
Motion Direct Drive On (MDO) on page 56
 
Motion Redefine Position (MRP) on page 149 
 
Process type motion instructions initiate motion processes that can take an 
indefinite amount of time to complete. 
Examples of process type instructions include the: 
•  Motion Arm Watch Position (MAW) instruction 
•  Motion Axis Move (MAM) instruction 
Process type instructions work as follows: 
1.  When the rung that contains the motion instruction becomes true, the 
controller: 
Instructions