Rockwell Automation 21G PowerFlex 750-Series AC Drives Reference Manual - Manual (Page 25)

Rockwell Automation Publication 750-RM001F-EN-P - February 2012 25
About the PowerFlex Safe Speed Monitor Option Module Chapter 2
Disabled Mode
When P21 [Safety Mode] = 0 “Disabled” and P6 [Operating Mode] = 1 “Run”
all safety functions are disabled. Input, output, or speed monitoring diagnostics
do not take place and all outputs are in their safe state. Motion power is enabled
for drive commissioning in this mode.
Lock Monitoring
Lock monitoring helps prevent access to the hazard during motion. In many
applications, it is not sufficient for the machine to initiate a stop command once
the door has been opened because a high inertia machine may take a long time to
stop. Preventing access to the hazard until a safe speed has been detected may be
the safest condition. The lock monitoring feature is used to verify the operation
of the door locking mechanism.
Lock monitoring can be enabled on single units or on the first unit in a multi-axis
system. If the Lock Monitor input (LM_In) indicates that the door is unlocked
when the Door Control output (DC_Out) is in the locked state, or if the Lock
Monitor input indicates locked when the Door Monitor input (DM_In)
transitions from closed to open, the configured Safe Stop Type is initiated.
Safe Maximum Speed, Safe Maximum Acceleration, and Safe
Direction Monitoring
Three additional safety functions, Safe Maximum Speed (SMS), Safe Maximum
Acceleration (SMA) and Safe Direction Monitoring (SDM), operate
independent of the other modes, relying on the Safe Stop function. When you
configure the safety option for Safe Maximum Speed, the feedback velocity is
monitored and compared against a user-configurable limit. If the measured
velocity is greater than or equal to the limit, the configured Safe Stop Type is
executed.
When Safe Acceleration Monitoring is enabled, the option monitors the
acceleration rate and compares it to a configured Safe Maximum Acceleration
Limit. If acceleration is detected as greater than or equal to the Safe Maximum
Acceleration Limit, an Acceleration fault occurs. If an Acceleration fault is
detected while the option is actively monitoring motion, the configured Safe
Stop Type is initiated.
Safe Direction Monitoring is also activated via option configuration. The option
monitors the feedback direction and executes the configured Safe Stop Type
when motion in the illegal direction is detected.
Refer to Chapter 9 for detailed information on these functions.
IMPORTANT The safety option monitors motion for Safe Stop in every mode except
Disabled.