526 Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018
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MOTION_INSTRUCTION Bit Leg Definitions for MDAC
Mnemonic Description
.EN (Enable) Bit 31 The enable bit is set when the rung transitions from false-to-true and
stays set until the rung goes false.
.DN (Done) Bit 29 The done bit is set when the Master Driven Axis Control instruction is
successfully initiated.
.ER (Error) Bit 28 The error bit is set when there is an invalid combination of parameters in
the MDAC instruction.
.IP (In Process) Bit 26 The in process bit is set when the MDAC instruction is activated and reset
by an instruction (for example, the MASD instruction).
.AC (Active) Bit 23 The active bit is set when a move (MAJ, MAM or MATC) goes IP in Master
Driven mode on the axis that is selected as the Slave Axis of the MDAC
instruction. If the Slave Axis is started in Time Driven mode, then the AC
bit of the MDAC does not go active. The IP bit of the MDAC instruction
does not change at this time.
Description
The MDAC instruction is used to select a single axis as a Master Axis and a single
axis as a Slave Axis. The MDAC instruction connects a Master and Slave Axis for a
MAM, MAJ, and MATC instruction. When an MDAC is executed (goes IP), the
specified Slave Axis in the MDAC instruction is logically geared with the
designated Master Axis. After motion on both the Master and Slave Axes has been
initiated, the Slave follows the Master Axis motion using the programmed
dynamics of the motion instruction.
There are no changes in any active motion when a new MDAC instruction is
activated. Activating a new MDAC instruction puts the parameters programmed
in the MDAC into a pending state. The parameters in the pending MDAC
instruction are overridden if you execute a succeeding MDAC before a new single
axis motion instruction (MAM, MAJ, and MATC) is activated on the slave axis.
The most recent values in the pending MDAC instruction are used when a new
single axis motion instruction is activated on the Slave Axis.
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