Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018  125 
Master Driven Speed Control (MDSC) Merging and Replacement Mode for 
MAM 
When programmed in units of seconds, the MAM instruction must start at rest 
(that is, both start velocity and acceleration must be equal to 0.0). If programmed 
in units of seconds or Master Units, a runtime error will occur for the MAM on 
the Slave if the instruction is activated when not at rest. 
Master Driven Speed Control (MDSC) and Motion Direct Command 
Support   
The Motion Direct commands are not available in the instruction tree for the 
MDAC instruction. You must program an MDAC in one of the supported 
programming languages before you execute an MAM in Time Driven Mode. A 
runtime error will occur if an MDAC is not previously executed in an MAM or 
MAJ in Master Driven Mode. 
The Motion Direct Command supports the MDSC enumerations speed, 
acceleration, deceleration, and Jerk for MAM.   
Note that Event Distance and Calculated Data are not supported parameters for 
the MAM and Motion Direct Command. 
Master Driven Speed Control (MDSC) and CIP Axis Manual Tune and 
Motion Generator 
Event Distance and Calculated Data parameters are not supported for MAM.   
See also 
Troubleshoot Axis Motion on page 608
 
Structured Text Syntax on page 635 
Motion Error Codes (ERR) on page 557 
Motion Move Instructions on page 83 
Common Attributes on page 663 
This information applies to the CompactLogix 5370, ControlLogix 5570, 
Compact GuardLogix 5370, GuardLogix 5570, Compact GuardLogix 5380, 
CompactLogix 5380, CompactLogix 5480, ControlLogix 5580, and GuardLogix 
5580 controllers. Controller differences are noted where applicable. 
The Motion Axis Gear (MAG) instruction provides electronic gearing between 
any two axes in a specified direction and at a specified ratio. When called, the 
specified Slave Axis is geared to the Master Axis at the specified Ratio (for