Multi-Axis Coordinated Motion Instructions 
 
496  Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018 
See also   
Input and Output Parameters Structure for Coordinate System Motion 
Instructions on page 511 
The following table describes the predefined data type status bits for motion 
instruction MCLM and MCCM. 
Bit Name  Meaning 
FLAGS   
EN   
DN   
ER   
PC   
IP   
AC   
ACCEL  Set as expected during motion. It is independent of Master acceleration.   
The ACCEL bit on the instruction driving the Slave Coordinate System (for 
example, MCLM) is set as the Slave Coordinate System is accelerating to its 
commanded speed. This bit is insensitive to acceleration occurring on the 
Master Axis. 
However, the AccelStatus bit, which is in the MotionStatus word of the Slave 
Coordinate System (not the instruction driving the Slave Coordinate System), is 
set or cleared based on changes in velocity of the Slave Coordinate System. 
DECEL  Set as expected during motion. It is independent of Master deceleration.   
The DECEL bit on the instruction driving the Slave Coordinate System is set as 
the Slave Coordinate System is decelerating to its commanded speed. This bit is 
insensitive to deceleration occurring on the Master Axis. 
However, the DecelStatus bit, which is in the MotionStatus word of the Slave 
Coordinate System (not the instruction driving the slave axis), is set or cleared 
based on changes in velocity of the Slave Coordinate System. 
TrackingMaster  Indicates that the Slave Coordinate System is tracking the Master Axis (only 
used in Master Driven Mode). 
When an instruction is initiated in Master Driven Mode, the Slave Coordinate 
System accelerates to the speed that is programmed for MDSC mode. The 
Tracking Master is set when the acceleration is complete in MDSC Mode. This 
means that the Slave Coordinate System is synchronized to the Master Axis. 
The Tracking Master bit is cleared when any of the following occurs on the Slave 
Coordinate System: 
•  When the Slave Coordinate System starts to either accelerate or decelerate 
for any reason, for example, for an MCCD or an MCS being issued. 
•  When the Slave Coordinate System is relinked to another Master Axis. In this 
situation, the TrackingMaster bit is first cleared and then it is set again in the 
new instruction status word when the Slave Coordinate System starts 
tracking the new Master Axis again.   
•  The Slave Coordinate System is stopped. The Tracking Master is cleared as 
soon as the stop is initiated on the Slave Coordinate System. 
This bit is never set when LockDir = NONE. 
Note that the Tracking Master bit on the Slave Coordinate System is not affected 
by any operation (for example, MCS, MCCD) on the Master Axis. 
The Tracking Master bit is always cleared in Time Driven Mode. 
Instructions (MCLM, MCCM) 
when MDCC Is Active