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Rockwell Automation Publication 2080-UM002L-EN-E - November 2021
Chapter 7 Motion Control
Soft Limits are activated only when the corresponding axis is homed. Users
can enable or disable soft limits, and configure an upper and lower limit
setting through the Connected Components Workbench software.
When a soft limit is enabled, the axis comes to a stop when the limit is detected
during motion. The motion is stopped using emergency stop parameters.
If both hard and soft limits are configured as enabled, for two limits in the
same direction (upper or lower), the limits should be configured such that the
soft limit is triggered before the hard limit.
PTO Pulse Limits
This limit parameter is not configurable by the user and is the physical
limitation of the embedded PTO. The limits are set at 0x7FFF0000 and -
0x7FFF0000 pulses, for upper and lower limits, respectively.
PTO pulse limits are checked by the controller unconditionally — that is, the
checking is always ON.
On a non-continuous motion, to prevent a moving axis going to ErrorStop
status with Motion PTO Pulse limits detected, user needs to prevent current
position value going beyond PTO Pulse limit.
On a continuous motion (driven by MC_MoveVelocity function block), when
the current position value goes beyond PTO pulse limit, PTO pulse current
position will automatically roll over to 0 (or the opposite soft limit, if it is
activated), and the continuous motion continues.
For a continuous motion, if the axis is homed, and the soft limit in the motion
direction is enabled, soft limit will be detected before PTO pulse limit being
detected.
Motion Stop
There are three types of stops that can be configured for an axis.
Soft Limits Checking on the Function Blocks
Function Block
Limits Checking
MC_MoveAbsolute
The target position will be checked against the soft limits before motion starts.
MC_MoveRelative
MC_MoveVelocity
The soft limits will be checked dynamically during motion.
