Motion Event Instructions
260 Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018
To successfully execute a MDR instruction, the targeted axis must be configured as
either a Servo or Feedback Only axis. Otherwise, the instruction errors.
Important:
The instruction execution may take multiple scans to execute because it
requires multiple coarse updates to complete the request. The Done (.DN)
bit is not set immediately, but only after the request is completed.
In this transitional instruction, the relay ladder, toggle the Rung-condition-in
from cleared to set each time the instruction should execute.
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. See Common Attributes for operand-related
faults.
Execution
Ladder Diagram
Condition/State Action Taken
Prescan The .EN, .DN, .ER, and .IP bits are cleared to false.
Rung-condition-in is false The .EN bit is cleared to false if either the .DN or .ER bit is true.
Rung-condition-in is true The .EN bit is set to true and the instruction executes.
Postscan N/A
Structured Text
Condition/State Action Taken
Prescan See Prescan in the Ladder Diagram table.
Normal execution See Rung-condition-in is false, followed by rung is true in the Ladder Diagram
table.
Postscan See Postscan in the Ladder Diagram table.
Error Codes
See Motion Error Codes (.ERR) for Motion Instructions.