Motion State Instructions
Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018 79
Execution
Ladder Diagram
Condition/State Action Taken
Prescan The .EN, .DN, and .ER are cleared to false.
Rung-condition-in is false The .EN bit is cleared to false if the .DN or .ER bit is true.
Rung-condition-in is true The .EN bit is set to true and the instruction executes. If
the EN bit is set to false, there is no action taken,
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.
Extended Error Codes
Extended Error Codes provide additional instruction specific information for the
Error Codes that are generic to many instructions. See Motion Error Codes (.ERR)
for Motion Instructions. The following Extended Error codes help to pinpoint the
problem when the MSO instruction receives a Servo Message Failure (12) error
message.
Extended Error Code (decimal) Associated Error Code (decimal) Meaning
Object Mode conflict (12) SERVO_MESSAGE_FAILURE (12) Axis is shutdown.
Process terminated on request (15) SERVO_MESSAGE_FAILURE (12) Enable input switch error.
(SERCOS)
Device in wrong state (16) SERVO_MESSAGE_FAILURE (12) Device State not correct
for action. (SERCOS)
MSO Changes to Status Bits
Axis Status Bit
Bit Name State Meaning
ServoActionStatus TRUE Axis is in Servo Control state with the servo loop active.
DriveEnableStatus TRUE The axis drive enable output is active.