Motion State Instructions
52 Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018
MOTION_INSTRUCTION Structure
Mnemonic Description
.EN (Enable) Bit 31 It is set when the rung makes a false-to-true transition and remains set until
the servo message transaction is completed and the rung goes false.
.DN (Done) Bit 29 It is set when the axis' drive signals have been successfully disabled and the
drive enable status bit is cleared.
.ER (Done) Bit 28 It is set to indicate that the instruction detected an error, such as if you
specified an unconfigured axis.
Description
For motion module’s with an external servo drive interface, the MDF instruction
directly disables the motion module Drive Enable output of the specified physical
axis and also zeroes the modules' servo output to the external drive by applying the
configured Output Offset value.
The MDF instruction is used to stop motion initiated by a preceding Motion
Direct Drive On (MDO) instruction and transition the axis from the Direct
Drive Control state back to the Axis Ready state.
To successfully execute an MDF instruction, the targeted axis must be configured
as a Servo 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.
This is a transitional instruction:
• In relay ladder, toggle the EanbleIn false to true each time the instruction
should execute.
• In structured text, condition the instruction so that it only executes on a
transition.
Master Driven Speed Control (MDSC) and the MDF instruction
The MDF instruction goes in conjunction with the MDO on an analog axis. If an
MDF is issued in Master Driven Mode, the system shuts the servo drive off.
The IP bit of the Master Driven Axis Control (MDAC) instruction does not
change on a servo drive that is turned off.
The AC bit of the MDAC instruction resets when the axis stops as it is turned off.
Affects Math Status Flags
No
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